Technical Ducato Comfortmatic and/or CANBUS issues

[bazmonaut]

So... Comfortmatic will go into 1st or reverse when the engine is not running, but when the engine is running I get the 'gear unavailable' message and some soothing beeping.

Due to error codes in the gearbox ECU, I suspect there is an issue with the CANBUS and am seeking some advice on where to start checking wires and cleaning contacts. Specifically: where is the gearbox module physically located? Is there a CANBUS amplifier or other control unit somewhere?

I have read many posts about earth strap and the wires behind the wiper motor and left side headlight. I did have the windscreen scuttle issue but used some tape and sikaflex to fix it, but I still get water ingress into the engine bay and have seen water on the loom behind the passenger side headlight...

Some history of the problem and troubleshooting:


This first happened a couple of months ago, and the garage said they cleared the codes and reset some gearbox parameters and all was well (until now...). It has happened again, so I thought I would have a go, rather than be recovered again...

So, I have bought an OBDLink interface and Multiecuscan. I can see what I need to do when in 'simulation' mode, but I cannot connect to the gearbox module... or any module at all. I can 'Scan DTC' and see error codes, which I have done. I have posted a question on the Multiecuscan forum, but I suspect my issue is actually Ducato-specific, to do with the wiring loom and electrical contacts...

Initially I saw U0001-88 error code, but after I cleared codes that one went away. After several rounds of clearing codes and trying to get it into gear, we are now settled on the following error codes presented by the gearbox control module:

Gearbox / TCM/NCA/NCR (Automatic Transmission)
Marelli SELESPEED CFC348 Automatic Gearbox
ISO Code: BC 07 A2 8A C4
Hardware number: CFC 348F.09 - Ver: 00
Software number: FGC11IOF - Ver: 0000
Errors found:
P0857-86 - VDC messages (from CAN) - Signal/message invalid
P0856-81 - VDC messages (from CAN) - Invalid serial data received

The key here I think are the CAN errors: the gearbox is expecting messages but not recieving them. I suspect a short or open circuit somewhere.


So I suspect this is why it won't go into gear when the engine is running, but will when it isn't (the garage confirmed that there is nothing mechnically wrong with the gearbox, and I can hear it happily selecting 1st and reverse when the engine is off). The above codes are to do with traction control, and I think it's a safety feature. After a while of trying to get it into gear I often get the 'hill assist unavailable, and 'ESP unavailable' error messages too...

Anyone seen this before? I saw a post on another forum but it was from years ago and sadly the OP did not post a resolution...

 

[varesecrazy]

Generally...

The brake pedal switch is common to many of these features..

Worth checking that cheap and simple item 1st

 

[bazmonaut]

Well... as I am stranded in a very nice place by the seaside, I decided I may as well have a dig about under the bonnet and see what can be seen.

Pulled the passenger side headlamp and had a look: very wet behind there. The pipe from the scuttle missing. Made up a new one and routed it past all those electrics.

Pulled, inspected, replaced about 4 connectors under the headlight, including two blanked ones and the big one next to the ABS unit. The larger one of the two blanks was very wet. Dried it off as best I could.

Replaced everything, hopped back in the cab and started it as I have so many times in forlorn hope that my aimless fiddling had actually done any good...

Bugger me if it didn't go into gear sweet as you like. Yes, for once, for very once, a bit of fiddling seems to have done some good.

Having read many many sad posts on Comfortmatic issues I am very pleased to post this conclusion. :slayer:

 

[bazmonaut]

So I thought I would post again to try and help anyone else with the same Comfortmatic 'gear unavailable' issue.

Symptoms: the gearbox will happily select R, N and 1st when the engine is not running, but when the engine is running displays the 'gear unavailable' message on the dash.

Sometimes I have to turn the ignition on and off a few times for this to happen, if I have just recieved the 'gear unavailable' message. This test checks that there are no mechanical issues with the gearbox. If yours doesn't select at all then maybe you don't have the same problem as me.

I can usually clear the problem by disconnecting the battery for 15 minutes. This seems to reset the grumpy gearbox ECU. Recently the problem was occurring more and more frequently, like up to 3 times a week. So, I felt I needed to try some fixes before it stranded me for real.

I noticed that I get the error message under specific cicumstances: if the vehicle battery voltage is a bit low (say below 12.3v), also if the engine has not started on the first key turn. I have read a LOT about possible causes, and someone said that changing their battery from a 100Ah to the recommended 110Ah fixed the issue (mine is the 3.0lt). This didn't make a lot of sense to me, but as the problems started to appear when I installed a new (Varta) 100Ah battery a few months earlier... I thought it was worth a try.

So I installed a 020 Varta I1 Silver Dynamic 110Ah 920CCA

I have had this battery in for two months now and have not had the 'gear unavailable' issue at all during this period.

I carefully monitor the battery voltage, and find that is is generally higher than with the 100Ah battery. I do not think that the battery is the root cause, rather that a weak battery makes the problem worse, while the vehicle is able to cope when it has a stronger battery.

I believe that the real issue is the CANBUS signalling between the engine ECU and the gearbox ECU. I have long suspected that the gearbox ECU was recieving corrupt signalling from the engine ECU. This is why the problem only existed when the engine was running. The gearbox ECU is sensibly refusing to put the vehicle in motion while it is not getting good data about engine speed and other parameters.

I have also been trying to install an aftermarket cruise control. This aftemarket device is refusing to initialise, so I put a PC oscilliscope on the CANBUS H and L lines at the OBD2 port under the dash, to check whether a CANBUS signal was present. I found that the signal on CAN-L was below 200mV when at rest - this should be around 2.5V when at rest dropping to 0.5V. So, clearly there is a problem with CAN-L. I believe that this is the root cause of the 'gear unavailable' problems I have been having.

FYI the PC oscilloscope I used was a cheap one (£50 off Amazon), it's a Hantek 6022BE. There are some YouTube videos about how to use it to diagnose CANBUS issues.

I am going to start another thread about CANBUS issues, but having spent a LOT of time searching around for solutions to my Comfortmatic problem, I hope that someone finds this analysis useful.

B

 

[theoneandonly]

So I thought I would post again to try and help anyone else with the same Comfortmatic 'gear unavailable' issue.

Symptoms: the gearbox will happily select R, N and 1st when the engine is not running, but when the engine is running displays the 'gear unavailable' message on the dash.

Sometimes I have to turn the ignition on and off a few times for this to happen, if I have just recieved the 'gear unavailable' message. This test checks that there are no mechanical issues with the gearbox. If yours doesn't select at all then maybe you don't have the same problem as me.

I can usually clear the problem by disconnecting the battery for 15 minutes. This seems to reset the grumpy gearbox ECU. Recently the problem was occurring more and more frequently, like up to 3 times a week. So, I felt I needed to try some fixes before it stranded me for real.

I noticed that I get the error message under specific cicumstances: if the vehicle battery voltage is a bit low (say below 12.3v), also if the engine has not started on the first key turn. I have read a LOT about possible causes, and someone said that changing their battery from a 100Ah to the recommended 110Ah fixed the issue (mine is the 3.0lt). This didn't make a lot of sense to me, but as the problems started to appear when I installed a new (Varta) 100Ah battery a few months earlier... I thought it was worth a try.

So I installed a 020 Varta I1 Silver Dynamic 110Ah 920CCA

I have had this battery in for two months now and have not had the 'gear unavailable' issue at all during this period.

I carefully monitor the battery voltage, and find that is is generally higher than with the 100Ah battery. I do not think that the battery is the root cause, rather that a weak battery makes the problem worse, while the vehicle is able to cope when it has a stronger battery.

I believe that the real issue is the CANBUS signalling between the engine ECU and the gearbox ECU. I have long suspected that the gearbox ECU was recieving corrupt signalling from the engine ECU. This is why the problem only existed when the engine was running. The gearbox ECU is sensibly refusing to put the vehicle in motion while it is not getting good data about engine speed and other parameters.

I have also been trying to install an aftermarket cruise control. This aftemarket device is refusing to initialise, so I put a PC oscilliscope on the CANBUS H and L lines at the OBD2 port under the dash, to check whether a CANBUS signal was present. I found that the signal on CAN-L was below 200mV when at rest - this should be around 2.5V when at rest dropping to 0.5V. So, clearly there is a problem with CAN-L. I believe that this is the root cause of the 'gear unavailable' problems I have been having.

FYI the PC oscilloscope I used was a cheap one (£50 off Amazon), it's a Hantek 6022BE. There are some YouTube videos about how to use it to diagnose CANBUS issues.

I am going to start another thread about CANBUS issues, but having spent a LOT of time searching around for solutions to my Comfortmatic problem, I hope that someone finds this analysis useful.

B

first things first
This solves/helps remove battery paranoia

4qIYlttntL1vVyiRUWF%2BVyPmf1IXdF2ibIbJjjv8Dfw98l2gg0uKuy35rGxVHUD713BEX3b9mSBqURWIcWBfvpeGhqJ1y49nFQ29bSfrTWgp0oxGmQMUkzaIjWOn0VxZJ4|tkp%3ABFBMitGZn6Jg

a simple BT battery monitor , i have one. helps with airbag paranoia too.

back to Multiecuscan. If you have an error code look at it , it will have freeze frame data associated with it and even some "help". Take a screenshot of it . it will provide a lot more info than "i got a P0xyz"
Looking forward to your tutorial on how to diagnose any thing with a cheap scope £50 is it worth it? if so im in (well christmas list at least)

 

[Seanwinder22]

Well... as I am stranded in a very nice place by the seaside, I decided I may as well have a dig about under the bonnet and see what can be seen.

Pulled the passenger side headlamp and had a look: very wet behind there. The pipe from the scuttle missing. Made up a new one and routed it past all those electrics.

Pulled, inspected, replaced about 4 connectors under the headlight, including two blanked ones and the big one next to the ABS unit. The larger one of the two blanks was very wet. Dried it off as best I could.

Replaced everything, hopped back in the cab and started it as I have so many times in forlorn hope that my aimless fiddling had actually done any good...

Bugger me if it didn't go into gear sweet as you like. Yes, for once, for very once, a bit of fiddling seems to have done some good.

Having read many many sad posts on Comfortmatic issues I am very pleased to post this conclusion. :slayer:

Did you ever sort this mate ? I had this issue it was a broken terminal connector on the harness going to the gear box that sorted my problem but now I’ve got a few other codes come up camshaft and lambda sensor so I’m thinking same problem a connection issue what area did you check with wiring

 

[Canex]

So I thought I would post again to try and help anyone else with the same Comfortmatic 'gear unavailable' issue.

Symptoms: the gearbox will happily select R, N and 1st when the engine is not running, but when the engine is running displays the 'gear unavailable' message on the dash.

Sometimes I have to turn the ignition on and off a few times for this to happen, if I have just recieved the 'gear unavailable' message. This test checks that there are no mechanical issues with the gearbox. If yours doesn't select at all then maybe you don't have the same problem as me.

I can usually clear the problem by disconnecting the battery for 15 minutes. This seems to reset the grumpy gearbox ECU. Recently the problem was occurring more and more frequently, like up to 3 times a week. So, I felt I needed to try some fixes before it stranded me for real.

I noticed that I get the error message under specific cicumstances: if the vehicle battery voltage is a bit low (say below 12.3v), also if the engine has not started on the first key turn. I have read a LOT about possible causes, and someone said that changing their battery from a 100Ah to the recommended 110Ah fixed the issue (mine is the 3.0lt). This didn't make a lot of sense to me, but as the problems started to appear when I installed a new (Varta) 100Ah battery a few months earlier... I thought it was worth a try.

So I installed a 020 Varta I1 Silver Dynamic 110Ah 920CCA

I have had this battery in for two months now and have not had the 'gear unavailable' issue at all during this period.

I carefully monitor the battery voltage, and find that is is generally higher than with the 100Ah battery. I do not think that the battery is the root cause, rather that a weak battery makes the problem worse, while the vehicle is able to cope when it has a stronger battery.

I believe that the real issue is the CANBUS signalling between the engine ECU and the gearbox ECU. I have long suspected that the gearbox ECU was recieving corrupt signalling from the engine ECU. This is why the problem only existed when the engine was running. The gearbox ECU is sensibly refusing to put the vehicle in motion while it is not getting good data about engine speed and other parameters.

I have also been trying to install an aftermarket cruise control. This aftemarket device is refusing to initialise, so I put a PC oscilliscope on the CANBUS H and L lines at the OBD2 port under the dash, to check whether a CANBUS signal was present. I found that the signal on CAN-L was below 200mV when at rest - this should be around 2.5V when at rest dropping to 0.5V. So, clearly there is a problem with CAN-L. I believe that this is the root cause of the 'gear unavailable' problems I have been having.

FYI the PC oscilloscope I used was a cheap one (£50 off Amazon), it's a Hantek 6022BE. There are some YouTube videos about how to use it to diagnose CANBUS issues.

I am going to start another thread about CANBUS issues, but having spent a LOT of time searching around for solutions to my Comfortmatic problem, I hope that someone finds this analysis useful.

B

Hi, I know this was last year but I have exactly the same problem. I've tried everything but still can't get it to go into gear once the engine is running - UNLESS I put it straight into gear before the ECUs talk to each other,!! It then goes in with a loud clunk & I don't know if it will drive then as I'm parked on top of a cliff in Wales!
Any ideas how to reset the gbox ECU ? I've tried disconnecting battery but nothing & I haven't got a decent odb code reader (trying to get one locally)

Cheers
Chris

 

[bazmonaut]

Hi, I know this was last year but I have exactly the same problem. I've tried everything but still can't get it to go into gear once the engine is running - UNLESS I put it straight into gear before the ECUs talk to each other,!! It then goes in with a loud clunk & I don't know if it will drive then as I'm parked on top of a cliff in Wales!
Any ideas how to reset the gbox ECU ? I've tried disconnecting battery but nothing & I haven't got a decent odb code reader (trying to get one locally)

Cheers
Chris

Hey Chris - I think clearing the codes is your best bet if you're stranded and just need to get going. If you're taking it to a garage then probably best that you don't clear them. I found that disconnecting the battery for 15 minutes would sometimes work, and sometimes not.

I'm not sure that I would force the issue, clunking is not good. If the engine is off and it will still change gear then your mechnics are likely OK. Changing the battery certainly fixed my issue... for a while.

My gearbox journey is ongoing. I had starting issues which got worse over a few weeks. By starting issues I mean slow cranking. I checked & changed the battery: no improvement. A failed start could sometimes result in the dreaded 'gear unavailable' message. This got worse and worse. I had it booked it with a garage, but as I live in it I have no choice but to drive is at least occasionally while waiting for the appointment. I didn't know whether the gearbox had a problem or if it was down to the starting issue confusing its poor little brain.

A few weeks ago it suddenly got much worse, and was clearly a gearbox issue and not a starying issue. I managed to get it into gear but it was very clunky which was a very different failure mode to what I had experienced before. Over the course of a day it got worse and worse, refusing to go into gear, changing with a bang, or popping out into neutral. Eventually it got so bad I didn't want to risk doing more damage, so I had it towed. This time the gearbox issues were mechnical, and I had my clutch master cylinder, dual mass flywheel and clutch replaced, along with the starter motor (which had been damaged by the flywheel and was the cause of the starting issues) and sundry related bits and bobs, which was £3.5k all up. The clutch master cylinder was £950. Gulp.

I'm now in France for the summer, and it's runing lovely. I didn't really have that money to spend but I'm glad it went before my trip.

It is difficult finding a garage that knows much about these gearboxes. I am very fortunate to have found TJH Auto in Barnstaple, they are a great garage, very honest, and they have a couple of people who know these gearboxes. https://tjhauto.co.uk/ They work on the council's fleet of vans as well as motorhomes etc.

Best of luck Chris

 

[Canex]

Hey Chris - I think clearing the codes is your best bet if you're stranded and just need to get going. If you're taking it to a garage then probably best that you don't clear them. I found that disconnecting the battery for 15 minutes would sometimes work, and sometimes not.

I'm not sure that I would force the issue, clunking is not good. If the engine is off and it will still change gear then your mechnics are likely OK. Changing the battery certainly fixed my issue... for a while.

My gearbox journey is ongoing. I had starting issues which got worse over a few weeks. By starting issues I mean slow cranking. I checked & changed the battery: no improvement. A failed start could sometimes result in the dreaded 'gear unavailable' message. This got worse and worse. I had it booked it with a garage, but as I live in it I have no choice but to drive is at least occasionally while waiting for the appointment. I didn't know whether the gearbox had a problem or if it was down to the starting issue confusing its poor little brain.

A few weeks ago it suddenly got much worse, and was clearly a gearbox issue and not a starying issue. I managed to get it into gear but it was very clunky which was a very different failure mode to what I had experienced before. Over the course of a day it got worse and worse, refusing to go into gear, changing with a bang, or popping out into neutral. Eventually it got so bad I didn't want to risk doing more damage, so I had it towed. This time the gearbox issues were mechnical, and I had my clutch master cylinder, dual mass flywheel and clutch replaced, along with the starter motor (which had been damaged by the flywheel and was the cause of the starting issues) and sundry related bits and bobs, which was £3.5k all up. The clutch master cylinder was £950. Gulp.

I'm now in France for the summer, and it's runing lovely. I didn't really have that money to spend but I'm glad it went before my trip.

It is difficult finding a garage that knows much about these gearboxes. I am very fortunate to have found TJH Auto in Barnstaple, they are a great garage, very honest, and they have a couple of people who know these gearboxes. https://tjhauto.co.uk/ They work on the council's fleet of vans as well as motorhomes etc.

Best of luck Chris

Thanks for the reply & advice
We've had this problem for 9 months now & keep thinking we've solved it but obviously we havent
I'm thinking my problem is electrics & hoping clearing the codes will just get us going again as we are in the most awkward place - down a steep path under a bridge up a steep hill the other side!! I doubt a low loader will get to us in which case the farmer will have to try & tow us out
If the codes can't be cleared we have no choice & I'll get it taken to my mechanic who is willing to have another look - he found a blown fuse last time.
My initial problem was the hydraulic pump wouldn't run - I found a bad connector & cleaned it & it worked last year but that has been soldered now & the pump is running ok so it's not that. That was also the problem with the blown fuse - stopped the pump running.
I've just had a video call with a chap who had similar problems & it was his gbox ECU - I've took it off & cleaned/sprayed all connections with switch cleaner & still the same
There is also a problem with plastic parts breaking off the springs on the clutch plate apparently so it might be that but it runs sweet as a nut when it runs!
We've decided we have no choice but to get it home & get it stripped down & even rip all the wiring out to try & find the cause of the problem.
We can't get rid of it without loosing loads of money so will have to spend some on it but it's been spoiling our trips out as we're just waiting for it to fail each time we go out.
Glad u got yours fixed - just have to grin & bear the cost unfortunately!!

Cheers
Chris

 

[Canex]

Anyone know where this gearbox ECU is located?

 

[Canex]

Hey Chris - I think clearing the codes is your best bet if you're stranded and just need to get going. If you're taking it to a garage then probably best that you don't clear them. I found that disconnecting the battery for 15 minutes would sometimes work, and sometimes not.

I'm not sure that I would force the issue, clunking is not good. If the engine is off and it will still change gear then your mechnics are likely OK. Changing the battery certainly fixed my issue... for a while.

My gearbox journey is ongoing. I had starting issues which got worse over a few weeks. By starting issues I mean slow cranking. I checked & changed the battery: no improvement. A failed start could sometimes result in the dreaded 'gear unavailable' message. This got worse and worse. I had it booked it with a garage, but as I live in it I have no choice but to drive is at least occasionally while waiting for the appointment. I didn't know whether the gearbox had a problem or if it was down to the starting issue confusing its poor little brain.

A few weeks ago it suddenly got much worse, and was clearly a gearbox issue and not a starying issue. I managed to get it into gear but it was very clunky which was a very different failure mode to what I had experienced before. Over the course of a day it got worse and worse, refusing to go into gear, changing with a bang, or popping out into neutral. Eventually it got so bad I didn't want to risk doing more damage, so I had it towed. This time the gearbox issues were mechnical, and I had my clutch master cylinder, dual mass flywheel and clutch replaced, along with the starter motor (which had been damaged by the flywheel and was the cause of the starting issues) and sundry related bits and bobs, which was £3.5k all up. The clutch master cylinder was £950. Gulp.

I'm now in France for the summer, and it's runing lovely. I didn't really have that money to spend but I'm glad it went before my trip.

It is difficult finding a garage that knows much about these gearboxes. I am very fortunate to have found TJH Auto in Barnstaple, they are a great garage, very honest, and they have a couple of people who know these gearboxes. https://tjhauto.co.uk/ They work on the council's fleet of vans as well as motorhomes etc.

Best of luck Chris

Just an update on mine.
Got the codes cleared - kept saying hydraulic fluid low?? Now get code P2919-64 suggesting slave cylinder fault.
Eventually got it into gear by starting engine & putting into gear straight away - managed to get it off the cliffside we had been stuck on & it drove home no problem!!
Got it home -tried to pull o drive and 'no gear available'!
Anyway after much research I think it's the clutch plate which has small plastic parts on the 7 springs that break off & cause all the problems - so waiting for it to go & be pulled apart to see.
Do you know if yours had the plastic parts on the clutch plate & what year is it?

cheers
Chris

 

[theoneandonly]

So I thought I would post again to try and help anyone else with the same Comfortmatic 'gear unavailable' issue.

Symptoms: the gearbox will happily select R, N and 1st when the engine is not running, but when the engine is running displays the 'gear unavailable' message on the dash.

Sometimes I have to turn the ignition on and off a few times for this to happen, if I have just recieved the 'gear unavailable' message. This test checks that there are no mechanical issues with the gearbox. If yours doesn't select at all then maybe you don't have the same problem as me.

I can usually clear the problem by disconnecting the battery for 15 minutes. This seems to reset the grumpy gearbox ECU. Recently the problem was occurring more and more frequently, like up to 3 times a week. So, I felt I needed to try some fixes before it stranded me for real.

I noticed that I get the error message under specific cicumstances: if the vehicle battery voltage is a bit low (say below 12.3v), also if the engine has not started on the first key turn. I have read a LOT about possible causes, and someone said that changing their battery from a 100Ah to the recommended 110Ah fixed the issue (mine is the 3.0lt). This didn't make a lot of sense to me, but as the problems started to appear when I installed a new (Varta) 100Ah battery a few months earlier... I thought it was worth a try.

So I installed a 020 Varta I1 Silver Dynamic 110Ah 920CCA

I have had this battery in for two months now and have not had the 'gear unavailable' issue at all during this period.

I carefully monitor the battery voltage, and find that is is generally higher than with the 100Ah battery. I do not think that the battery is the root cause, rather that a weak battery makes the problem worse, while the vehicle is able to cope when it has a stronger battery.

I believe that the real issue is the CANBUS signalling between the engine ECU and the gearbox ECU. I have long suspected that the gearbox ECU was recieving corrupt signalling from the engine ECU. This is why the problem only existed when the engine was running. The gearbox ECU is
FYI the PC oscilloscope I used was a cheap one (£50 off Amazon), it's a Hantek 6022BE. There are some YouTube videos about how to use it to diagnose CANBUS issues.

I am going to start another thread about CANBUS issues, but having spent a LOT of time searching around for solutions to my Comfortmatic problem, I hope that someone finds this analysis useful.

B

Well for my sins i bought the cheapest picoscope, so your canbus tutorial will be appreciated.
My current need is to acess the ecu and crankshaft sensor (easiest at ecu, if i knew pinouts)
Have you found a wiring diagram for a x290 or even how to get at the ecu.

 

[McLeod001]

So... Comfortmatic will go into 1st or reverse when the engine is not running, but when the engine is running I get the 'gear unavailable' message and some soothing beeping.

Due to error codes in the gearbox ECU, I suspect there is an issue with the CANBUS and am seeking some advice on where to start checking wires and cleaning contacts. Specifically: where is the gearbox module physically located? Is there a CANBUS amplifier or other control unit somewhere?

I have read many posts about earth strap and the wires behind the wiper motor and left side headlight. I did have the windscreen scuttle issue but used some tape and sikaflex to fix it, but I still get water ingress into the engine bay and have seen water on the loom behind the passenger side headlight...

Some history of the problem and troubleshooting:


This first happened a couple of months ago, and the garage said they cleared the codes and reset some gearbox parameters and all was well (until now...). It has happened again, so I thought I would have a go, rather than be recovered again...

So, I have bought an OBDLink interface and Multiecuscan. I can see what I need to do when in 'simulation' mode, but I cannot connect to the gearbox module... or any module at all. I can 'Scan DTC' and see error codes, which I have done. I have posted a question on the Multiecuscan forum, but I suspect my issue is actually Ducato-specific, to do with the wiring loom and electrical contacts...

Initially I saw U0001-88 error code, but after I cleared codes that one went away. After several rounds of clearing codes and trying to get it into gear, we are now settled on the following error codes presented by the gearbox control module:

Gearbox / TCM/NCA/NCR (Automatic Transmission)
Marelli SELESPEED CFC348 Automatic Gearbox
ISO Code: BC 07 A2 8A C4
Hardware number: CFC 348F.09 - Ver: 00
Software number: FGC11IOF - Ver: 0000
Errors found:
P0857-86 - VDC messages (from CAN) - Signal/message invalid
P0856-81 - VDC messages (from CAN) - Invalid serial data received

The key here I think are the CAN errors: the gearbox is expecting messages but not recieving them. I suspect a short or open circuit somewhere.


So I suspect this is why it won't go into gear when the engine is running, but will when it isn't (the garage confirmed that there is nothing mechnically wrong with the gearbox, and I can hear it happily selecting 1st and reverse when the engine is off). The above codes are to do with traction control, and I think it's a safety feature. After a while of trying to get it into gear I often get the 'hill assist unavailable, and 'ESP unavailable' error messages too...

Anyone seen this before? I saw a post on another forum but it was from years ago and sadly the OP did not post a resolution...

Hi bazmonaut, I have just joined Fiatforum trying to find information about my 2014 3.0l Fiat motorhome which has ceased to go into gear suddenly with exactly the same symptoms you have listed in this post, same error messages. This thread doesn’t seem to have any viable solutions to solving the problem except for your fiddling behind the left front headlight. Some months ago the Gear unavailable light came on for a long time before finally a symbol came up showing the brake light. As I was by myself I had to flag down a passing motorist to check my brake lights and the right brake light had failed! After putting in a new one the gearbox problem went away, so nothing wrong with the gear selector. Now the problem light Gear unavailable has come on again and this time after going through all the motions, starting, stopping the engine, opening the drivers door and all the usual things, after many attempts a failure light briefly showed a yellow headlight failure, alternating between the bright red gear unavailable light! So,here I am stuck literally up the creek without a paddle. I believe the problem must be the engine ECU is receiving an electrical message from somewhere my OBD reader won’t tell me about and this is being interpreted as a drive ability problem showing up as a gear selection problem, which it isn’t. There is actually nothing wrong with the gearbox ECU, it’s just getting a message from the engine ECU saying Don’t drive, there is a problem somewhere. My question is How to find that problem? Have you found anything further in your experiments?

 

[Sparks1061]

Hi bazmonaut, I have just joined Fiatforum trying to find information about my 2014 3.0l Fiat motorhome which has ceased to go into gear suddenly with exactly the same symptoms you have listed in this post, same error messages. This thread doesn’t seem to have any viable solutions to solving the problem except for your fiddling behind the left front headlight. Some months ago the Gear unavailable light came on for a long time before finally a symbol came up showing the brake light. As I was by myself I had to flag down a passing motorist to check my brake lights and the right brake light had failed! After putting in a new one the gearbox problem went away, so nothing wrong with the gear selector. Now the problem light Gear unavailable has come on again and this time after going through all the motions, starting, stopping the engine, opening the drivers door and all the usual things, after many attempts a failure light briefly showed a yellow headlight failure, alternating between the bright red gear unavailable light! So,here I am stuck literally up the creek without a paddle. I believe the problem must be the engine ECU is receiving an electrical message from somewhere my OBD reader won’t tell me about and this is being interpreted as a drive ability problem showing up as a gear selection problem, which it isn’t. There is actually nothing wrong with the gearbox ECU, it’s just getting a message from the engine ECU saying Don’t drive, there is a problem somewhere. My question is How to find that problem? Have you found anything further in your experiments?

Hi, did you make any progress on this?

 

[McLeod001]

Hi, did you make any progress on this?

Hi Sparks, No nothing yet since Fiat in Australia are unhelpful in not letting me access their system scanner to investigate further. Another autoelectrician came with an unknown scanner which simply said Clutch bearing. Well we know that because it is not responding with engine running! The problem is the system will drop the clutch into Neutral no worries if the engine is started with the gearbox in 1 or R so I think the clutch mechanics are OK, it is some electronic interference that is stopping it from moving once the engine is started and no scanner is picking up what that interference is. I also tried jamming into gear immediately after starting before the red light came and it went into 1 with a crunch and the red light went out. I moved forward a few yards then selected R and put the van back into the temporary parking space I have thinking it probably better not to try on the open road in case mechanical damage might result. However this reinforced to me anyway what we’re talking about ie that there seems to be some curious electronic problem rather than mechanical? I’m currently waiting for a place in the huge waiting line for Fiat Australia, mid February 2024 which will cost megabucks to transport the van to Sydney, the nearest agent out here!

 

[Sparks1061]

Hi Sparks, No nothing yet since Fiat in Australia are unhelpful in not letting me access their system scanner to investigate further. Another autoelectrician came with an unknown scanner which simply said Clutch bearing. Well we know that because it is not responding with engine running! The problem is the system will drop the clutch into Neutral no worries if the engine is started with the gearbox in 1 or R so I think the clutch mechanics are OK, it is some electronic interference that is stopping it from moving once the engine is started and no scanner is picking up what that interference is. I also tried jamming into gear immediately after starting before the red light came and it went into 1 with a crunch and the red light went out. I moved forward a few yards then selected R and put the van back into the temporary parking space I have thinking it probably better not to try on the open road in case mechanical damage might result. However this reinforced to me anyway what we’re talking about ie that there seems to be some curious electronic problem rather than mechanical? I’m currently waiting for a place in the huge waiting line for Fiat Australia, mid February 2024 which will cost megabucks to transport the van to Sydney, the nearest agent out here!

Do you have a copy of MultiEcuScan? And have you checked the 2 fluid levels?

 

[jackwhoo]

Hi Sparks, No nothing yet since Fiat in Australia are unhelpful in not letting me access their system scanner to investigate further. Another autoelectrician came with an unknown scanner which simply said Clutch bearing. Well we know that because it is not responding with engine running! The problem is the system will drop the clutch into Neutral no worries if the engine is started with the gearbox in 1 or R so I think the clutch mechanics are OK, it is some electronic interference that is stopping it from moving once the engine is started and no scanner is picking up what that interference is. I also tried jamming into gear immediately after starting before the red light came and it went into 1 with a crunch and the red light went out. I moved forward a few yards then selected R and put the van back into the temporary parking space I have thinking it probably better not to try on the open road in case mechanical damage might result. However this reinforced to me anyway what we’re talking about ie that there seems to be some curious electronic problem rather than mechanical? I’m currently waiting for a place in the huge waiting line for Fiat Australia, mid February 2024 which will cost megabucks to transport the van to Sydney, the nearest agent out here!

There is a sensor on the clutch bearing assembly .......if the gearbox ecu is not getting sensible signals from the clutch bearing the gearbox ecu will likely not engage gear to protect the gearbox / engine/drive train from damage

You have had a code reader state clutch bearing..... probably bearing position sensor

 

[McLeod001]

There is a sensor on the clutch bearing assembly .......if the gearbox ecu is not getting sensible signals from the clutch bearing the gearbox ecu will likely not engage gear to protect the gearbox / engine/drive train from damage

You have had a code reader state clutch bearing..... probably bearing position sensor

Don’t have access to MultiECUScan in outback Aust so relying on auto electricians readouts. Jackwhoo, thanks but where can I find this sensor and why doesn’t scanner show this instead of just Thrust bearing? Looks like I’ll have to replace clutch plate and bearing in first instance as this seems to be a most probable answer considering all the forum notes regarding this series of dodgy clutch plates and plastic springs etc. If this doesn’t solve the problem at least then I’ll know whether it is an electronic or mechanical problem. Really appreciate inputs from you all.

 

[Sparks1061]

• Don’t have access to MultiECUScan in outback Aust so relying on auto electricians readouts. Jackwhoo, thanks but where can I find this sensor and why doesn’t scanner show this instead of just Thrust bearing? Looks like I’ll have to replace clutch plate and bearing in first instance as this seems to be a most probable answer considering all the forum notes regarding this series of dodgy clutch plates and plastic springs etc. If this doesn’t solve the problem at least then I’ll know whether it is an electronic or mechanical problem. Really appreciate inputs from you all.

Each to there own, but replacing the clutch and bearing as a first step seems to be a costly way of going, there are plenty of other cheaper things most of which you can do yourself and all of which have been reported as generating the same or similar error codes,
I have the same error code and originally had the same message, but once I switched to the correct gearbox version (MES has 2 options) I got the same error code but different message, I now get P2919-64 Gearbox control unit initialization failed
I have been working for a while with people off this and other forums as well as a gentleman in the UK who works on Comfortmatic gearboxes all the time and have so far done the following,

• Replaced the Earth straps,
• Replaced the Battery
• Replaced the brake switch
• Removed and cleaned all the electrical connectors
• Checked the fuses and Relays
• Checked the voltages to the TCU
• Changed and bled the Hydraulic fluid in the Robotic control box as well as the DOT fluid in the Clutch Actuator (The fluid in the clutch Actuator was filthy and the container had a layer of sludge in the bottom)

The only difference I have been able to find on the readings from MCS between my van and a working one is that the Clutch plate rotates on mine with the engine running which it should not be doing, so it might well be that the problem is the clutch, or could be the slave cylinder, it could also be that I need to re-bleed the Clutch actuator again, Havent been able to do any work sin ce before Christmas as we have not had temps about -14 C here since Christmas,
But as I was quoted 2500 Euros just to change the clutch I need to exclude every other possibility before I go that route!

BTW I assume It is Fiat Commercial you are taking the van too? Lots of stories of them just changing everything in sight until something works, which gets expensive very quickly! If I have to get the clutch changed I will take it to a local Garage that deals with Vans, and get them to just change the clutch and I will do the calibration myself,

Good Luck and let us know how you get on.

 

[McLeod001]

Each to there own, but replacing the clutch and bearing as a first step seems to be a costly way of going, there are plenty of other cheaper things most of which you can do yourself and all of which have been reported as generating the same or similar error codes,
I have the same error code and originally had the same message, but once I switched to the correct gearbox version (MES has 2 options) I got the same error code but different message, I now get P2919-64 Gearbox control unit initialization failed
I have been working for a while with people off this and other forums as well as a gentleman in the UK who works on Comfortmatic gearboxes all the time and have so far done the following,

• Replaced the Earth straps,
• Replaced the Battery
• Replaced the brake switch
• Removed and cleaned all the electrical connectors
• Checked the fuses and Relays
• Checked the voltages to the TCU
• Changed and bled the Hydraulic fluid in the Robotic control box as well as the DOT fluid in the Clutch Actuator (The fluid in the clutch Actuator was filthy and the container had a layer of sludge in the bottom)

The only difference I have been able to find on the readings from MCS between my van and a working one is that the Clutch plate rotates on mine with the engine running which it should not be doing, so it might well be that the problem is the clutch, or could be the slave cylinder, it could also be that I need to re-bleed the Clutch actuator again, Havent been able to do any work sin ce before Christmas as we have not had temps about -14 C here since Christmas,
But as I was quoted 2500 Euros just to change the clutch I need to exclude every other possibility before I go that route!

BTW I assume It is Fiat Commercial you are taking the van too? Lots of stories of them just changing everything in sight until something works, which gets expensive very quickly! If I have to get the clutch changed I will take it to a local Garage that deals with Vans, and get them to just change the clutch and I will do the calibration myself,

Good Luck and let us know how you get on.

Yep, done all the same things you mention and no change. Agree with probable cost but local garages here don’t have access to Fiat calibration equipment hence having to go to further afield at huge cost. Basically no choice. Will post results.