Technical Error Code B2400 ?

[Bouff1]

Hi all, my cousin owns a 2018 500x 2.0JTD auto with a mere 12k on the clock. It has recently gone into limp mode with the engine management light appearing and the stop start not working. The car has practically no power. I’ve taken it to my local garage who in fairness are very good at diagnosing most things, however when plugged into their computer it brings up code b2400 refer to dealer…. And they are unable to clear the code

Has anyone come across this code previously and possibly point me in the right direction ?

Many thanks in advance

 

[s130]

Are you sure the code is B2400 and not C2400

I only ask because my 500X eLEARN does not have a B2400, I can't find a B2400 in other listings. You state an AUTO gearbox and there is a C2400-55 code listed.

 

[Bouff1]

No, sadly it is a b2400 code. Both the garage and I were there interrogating Google when he had it plugged in with surprisingly little (I.e. no) results

 

[The Panda Nut]

Try google. This suggests oxygen sensor. I have had a fault caused by an exhaust system leak.

 

[Bouff1]

The only thing that comes up on Google is from this forum and in Italian which is “B2400=Circuito di massa potenziometro poggiatesta cortocircuito verso positivo”
Translated via Google translate is “Headrest potentiometer ground circuit shorted to positive”

Does it make any sense that a headrest has a potentiometer ?

 

[varesecrazy]

Does it make any sense that a headrest has a potentiometer ?

Possible..

Were you interrogating specific modules.. Or the car as a whole?

MultiECUscan will do it by module.. Anticipated to be under "Airbag"

 

[varesecrazy]

Your 2 x respondents are both from "Wales".. Which end is this car?

 

[Bouff1]

Your 2 x respondents are both from "Wales".. Which end is this car?

The cars ooop north (the best of course )

 

[Bouff1]

The garage interrogated the ECU and all modules but came up when scanning the ECU.

It was just b2400 dealer specific, please refer to dealer

 

[The Panda Nut]

lifted from Google
MFG - Manufacturer Specific codes, which have a '1' as their second digit to indicate they are unique to a particular vehicle make or model. These special codes were deemed necessary by the vehicle manufacturers so they could provide additional diagnostic information beyond the basic list of generic OBD II codes for all kinds of faults, not just emissions-related faults.

How To Fix B2400 ? Like the all engines, the car engine system employs specially developed hydraulic lifters (known as switching roller followers) for the B2400 code intake and exhaust valves. The lifters can be collapsed by disengaging an internal locking pin. The locking pin is disengaged using solenoids to alter oil pressure fed into the lifter.

B2400 Code Description:​

The catalytic converter has an oxygen sensor in front and behind it. When the vehicle is warm and running in closed loop mode, the upstream oxygen sensor waveform reading should fluctuate. When you see B2400 engine fault code on your engine code reader this description will help you.

B Codes

List of all Body codes.

Final Step: In the definitions listed below, there is a test drive recommended after you've completed any repairs to see if the condition is fixed. Before you take a test drive after a repair, always erase the B Code(s) first. This will turn the check engine light off and then you will know if the check engine light returns, you've got further diagnostics to complete.

 

[varesecrazy]

Lambda errors would Traditionally be a P series motor code

Strange..

 

[Bouff1]

It's all very strange. They couldn't clear the code despite trying to clear it 5 times, it immediately came back.

I'm waiting on a call back from a couple of dealers to see if they can help but I'm not going to hold my breath as they will no doubt want me to cross their palms with gold nuggets before they help

 

[The Panda Nut]

I think its worth saying headrest potentiometer... seems to refer to the stero. I think its a red herring. These computers spout such rubbish when they misbehave. I think its best to look at limp home mode and think it far more likely its something emissions re;ated. I would look at the the EGR valve and its signals and them the soot trap. Perhaps looking at the problem and thinking what is likely to throw it into limp home mode would be a positive step.

Before doing anything more, I would disconnect the battery and leave it for an hour or better still ovrnight, during which time charge the battery. CLean the battery terminals and check the earth is well secured.

I would then instruct it - via MRES -to relearn learned funtions as I think this code maybe a red herring. My Bravo had a mind of its own regarding its cruise control for example. It ised to get disorganised if it wasnt switched on cleanly. Stopping and getting out, locking up and then starting again , for instance, never failed to get it to reset and behave. Its very frustrating but probaly nothingtoo substantial

 

[Bouff1]

I've just had a bit of a thought. My cousin changed the battery prior to all this happening. I've had a look and it's a Numax 096 but I can't see that it's a stop.start battery - which this obviously is.

Does anyone know if this would throw the ECU if it was a standard non stop start battery fitted ?

 

[varesecrazy]

A device in a headrest to measure forces and calibrate airbag deployment does seem favourite..

Time will tell

 

[s130]

I've looked at the varoius responses re B2400 and as noted/observed B2400 could be / is a manufacturer specific code or possibly a rarer generic code.

Not sure what I'm saying or advising other than that Fiat should know *for your vehicle & chassis number* what that code actually means.

Speculating in these rarer cases might be less beneficial.