Technical P0340 error that keeps showing up no matter what I fix

[marco99goncalves]

Hello everyone, this might be a long post, since I want to be as detailed as possible since this problem has been happening for about a year (or more), and three mechanics have tried to fix it, but it always comes back again.. I'm also Portuguese, so some terms might not be correctly translated. I'll try my best, and I think everything is correct, but keep that in mind. I'm sorry if the post is hard to read or just too long, but I'm desperate since this has been going on for a really long time.

In August 2023, I bought a 2008 Fiat Bravo, 1.4 66Kw, Gasoline, which was later fitted with a Prins LPG system (this will be important). The car worked wonderfully for a while, but after a few months (I think around October 2023), the check engine light turned on (always steady, not blinking) when I made a particularly strong stop (though not super aggressive either, just strong by normal standards).

When the check engine light is on, the car takes a bit longer to start, but after that, everything feels the same. The only difference is the fact that it takes a few more seconds to turn on, but it doesn't seem to idle roughly, lose power, or anything else. For further reference, after checking with my OBD scanner (probably a bad one, though it's supposedly an ELM37, so it might not be the only error), I noticed that the car was giving a P0340 error, which is commonly a problem with the camshaft sensor, from what I gathered.

It's worth noting that the check engine light, in the beginning, only appeared when I was on LPG, and due to the light appearing, the LPG system would turn off. After running on gasoline for a while (maybe 30/50km), the light disappears, and I can use LPG again. This is will also be important later on.

I took it to a friend of my dad's, and he noticed that an injector was loose (very loose, in fact). The actual term might be ignition coil or cylinders, I'm not sure. In this image, which is not my engine but seems similar even though it's diesel, it's the leftmost cylinder, with the yellow things on top. He told me it wasn't worth repairing if the error didn't show up again, so he deleted the error and told me to go there if it turned on again. Well, it did, maybe around 20km later. He didn't fix the injector, just replaced the spark plugs, and that was it. It showed up once again a few kilometers later, and I decided to take it to another mechanic.

The new mechanic replaced the crankshaft sensor and the camshaft sensor. Everything seemed alright for a while, around 150km, but once again, it appeared. During the next few mechanic trips, we tried small repairs to check if the problems could be dirtiness on the wires, sensors, etc, but nothing seemed to last more than 50km.

Eventually, it got so bad that I couldn't use the LPG system for 10km without the light turning on. This led us to think that the problem was the LPG system, but after a while, the error would appear even when running on gasoline. While it would take longer, it also seemed to get more frequent with time, the same as what was happening with LPG, leading me to think that it's not related to the LPG system. It also eventually disappeared (without anything being done), even when running solely on gasoline (At this point, I hadn't used the LPG system in months), but it always showed up again eventually. Regardless, I had the LPG system checked, and the LPG repairman said everything was working well and no errors were showing up on the LPG system.

Also relevant, at this point, the light would turn on randomly, without any sudden stops or aggressive driving/launches.

Once again, I changed mechanics. This one immediately fixed the injector (or ignition coil/cylinder) problem, replaced the spark plugs, and changed the battery (a different issue). Nothing on the camshaft/crankshaft sensores, though. When I got it, the car worked wonderfully. The light didn't turn on even after 200km. I thought it was finally fixed. But today, the darn thing turned on again. This time, it took around 750km, and it was also at the same time I did a particularly strong launch, which is also similar to the reason the light turned on the first time.

So, do you guys have any idea what could be causing this? Is this a common problem? I've seen two videos saying that the P0340 error is common on the E-Torque engines, which seem to be the Fiat Bravo engines in Brazil, so I'm not sure it applies to my car. They both claim that the sensor should never be replaced by a non-original fiat sensor, but I'm not sure if that is true or not for my case. These are the videos I saw. They're in Portuguese, but it might be helpful for you anyway.

Video 1:
Video 2:


Is there anything I can try to do to get more information? I'm not knowledgable in cars at all, so anything that is relatively complicated needs to be a mechanic, but maybe I can try to check some things as long as they are simple. Is this a common problem in fiat bravos? I'm starting to get really desperate with this, especially considering that I can't use the LPG system while the light is turned on, even though the car seems to be completely fine, and it seems to be a sensor misreading or something like it.

If you guys want any specific pictures of the car, I can try to take them. Dissasembling some pieces might be hard for me, but I'll give it a shot.

Again, sorry for the long and complicated post, but I'm quite desperate with this, and this felt like the best place to get more info. I tried to bold the most important parts to make it easier to read, though.

 

[the green vanper]

Hello,

The eTorq engines in the Brazilian Bravo were completely different engines than the Europeans T-Jets and MultiJets. Brazilian market has its own rules, are engines have to be adapted to run on Ethanol.

Below the diagnostics procedure taken from FIAT's eLearn module for the above error on the 1,4 T-Jet 90 HP engine:

There are 4 different tables depending on what the error is. The diagnosis is though similar. But I think it's worth to point out that there are two problems that can lead to this fault: an electrical (like a short somewhere; and the fact that the problem appears with heavy gravity load - acceleration or braking might suggest that it could be the case), and a timing problem.

From what I read the problem was there when you bought the car. So I assume the seller knew about it. Have you got a servicing history? Do you know if the timing was changed on the car? Was it not long before he sold you the car?

Two eLearn docs attached, the tables reffer to it. I'm adding both EUR4 and EUR5 versions.

It's only a documentation, but might point to a good solution



Note that the ELM interface might not be to ideal one. FIATs are best to be diagnosed with MultiEcuScan. However the engine modules should communicate more or less properly with the majority of the pro error readers.

 

[marco99goncalves]

Thank you very much! That helps a lot, couldn't get any info before it!

As for the history, I don't know unfortunately, but funny you ask, I took it to the mechanic today and he asked me exactly that (and about the camshaft sensor too), which is the first time any of the mechanics asked me that, makes me think I'm in good hands! I'll get both replaced since I don't know the previous history on either, and I'd rather spend more money now and be sure that the timing is good and reliable.

As for the sensor, I asked if they could check if the original sensor is similar in terms of pricing when compared to aftermarket (he told me the aftermarket brands but I don't remember their names, but he told me they were good, well-know reliable brands). If they're similar in price, I might just take the plunge and buy it, since I've been told electrical issues are always best to solve with original parts.

Anyways, thank you for the help, I'll later update the post once I get news (hopefully good ones ) !

 

[the green vanper]

he asked me exactly that (and about the camshaft sensor too), which is the first time any of the mechanics asked me that, makes me think I'm in good hands!

Haha, I'm not a mechanic. I'm a linguist, with professionnal experience in sales & sales management (15+ years) and lately IT (12+)... So not so sure about that

Good luck with the mechanic and the repair, I hope you'll be able to finally fix the car!

 

[bsks]

Did a mechanic check if the timing of the engine is correct?

No signal from Camshaft Sensor P0340 Fault Code | FIAT Ulysse

Hi I recently rebuilt my 2.0 16v HDI engine after timing belt failure but now the car wont start. See my post on the Eurovan Forum: Ulysse 2.0 16V JTD 2004 Engine repair project I'm getting the P0340 fault from my PP2000 reader, Screenshots below. I have replaced the Cam sensor but still...

www.fiatforum.com

 

[marco99goncalves]

Did a mechanic check if the timing of the engine is correct?

No signal from Camshaft Sensor P0340 Fault Code | FIAT Ulysse

Hi I recently rebuilt my 2.0 16v HDI engine after timing belt failure but now the car wont start. See my post on the Eurovan Forum: Ulysse 2.0 16V JTD 2004 Engine repair project I'm getting the P0340 fault from my PP2000 reader, Screenshots below. I have replaced the Cam sensor but still...

www.fiatforum.com

Hello! Sorry for the late reply. I'm not sure, but I presume so. They recommended I change the timing belt (and water pump, I think), but I'm not sure if it's because they checked the timing. The first solution was to change the sensor and see if that would fix it, and later on, change the timing belt since we don't know when it was last changed. I ended up asking them to change both since I don't want the timing belt to have any problems anyway, and i'll be taking the car in next week.

In the mean time, the light has come on, even after changing the loose cylinder, but the light disappears quickly and takes way longer to come back on, so I'm guessing the loose cylinder was in fact playing a part in the problem, but there might be other problems.

I'm not entirely sure if the timing belt is what you mean by the timing of the engine, if not, sorry, I don't know a lot about this, but I will ask them when I take the car in

 

[marco99goncalves]

So, unfortunately, the error is still haunting me.

We replaced the timing belt, the water pump, and the camshaft sensor (it's not the original one, but I don't know the brand; the mechanic says it's a good one, though), but it still showed up.

Today we just replaced the crankshaft sensor for the original one ( Code on the invoice is 0000046815160, which seems to be a Bosch sensor? Not sure how to check it). Still hasn't shown up but only drove around 10/15km, so, who knows.

Anyhow, the mechanic isn't too optimistic about it being a problem with the crankshaft and expects the light to show up again. He asked me to confirm with some LPG technicians if it could be from the LPG system. The first technician I talked to said he was sure it wasn't, and when I mentioned that the camshaft sensor wasn't the original one, he was sure that was the problem. I still want to confirm with other LPG shops if it could in fact be the LPG system or if they all agree that it is most likely the non-original camshaft before talking to my mechanic again.

So, my question is: Do you guys think it could be the non-original camshaft sensor? I'm not too knowledgable on this, but many people have told me that non-original sensors very often give problems, but I'm not sure about the veracity of this. I'll try to get the info on the sensor that was installed and update the post later on with it.

Also, how can I check what the original sensors are? I can't seem to find any information on the forum or the internet in general.

 

[ZaphodB]

Sensors are either Bosch or Valeo

Get another OBD reader

 

[marco99goncalves]

Sensors are either Bosch or Valeo

Get another OBD reader

Are both OEM for my car, or do I have to figure out which is which? How can I find the original sensors so that I can buy them? Platforms like autodocs give a lot of sensors but don't tell me which one is OEM.

As for the OBD, yeah.. I plan on it, but right now I'm not the one reading the errors anyway, its the mechanic. Do you recommend one though?

 

[ZaphodB]

Just to clarify , when I said sensors are either Bosch or Valeo , I was talking generally.
Sure there might be other 3rd party ones, but the main players are Bosch and Valeo is what I'm saying.

As for getting OEM, just order the fiat part number from fiat , guaranteed OEM, a lot of 3rd party pattern parts will try and associate their part with that original part number (again generally)
So get the original part number first from eper... you're half way there then.

As for getting the part number , look in https://eper.fiatforum.com/en/Groups/F/F/BRO/3L

 

[the green vanper]

It seems that still no one knows what is the cause and they will be sending you from one to another It's always the case with aftermarket LPG installations. You have to find at least one serious mechanic.

Try checking for the part number in ePER with the VIN of your car. That shall limit the results. I've tried to check, but there are a couple of sensors that might be the camshaft sensor, I can't be sure.

As for the brands, FIAT frequently also uses Magneti Marelli as a supplier (it's an Italian company), so it IS POSSIBLE they were the producer of this sensor. However the car manufacturers are not willing to publish this information. Sometimes there are markings on the part or the packaging.

As @ZaphodB said, check the FIAT part number and order the OEM part at the dealership or online (ebay, amazon, etc), so you'll be sure you get the correct one.