Problems with Citroen DS3 Diesel: High fuel consumption, dark smoke and defective charge air temperature sensor

Hey, thanks for your help. My DS3 is the basic model - no special extras. It has 81335 KM on it so far and was last serviced about 10000 KM ago. I'll probably have it checked by a specialist, but I wanted to know what I need to be prepared for beforehand. Your experience with the engine control unit sounds similar, maybe that really is the culprit. I don't want to spend the 1000 euros, but that's the way it works, isn't it? Thanks again, your input was really helpful!

(Translated from German)

Hey, no problem, I'm happy to help! Your DS3 could actually have the same problems as my C3. The symptoms sound very similar. It could also be that it's actually the engine control unit, as you've already suspected. I would recommend reading out the fault memory first. Of course, it would be nice if you could avoid spending 1000 euros, I fully understand that. In my case, however, it was unfortunately unavoidable. I hope it's not that expensive for you. Whatever the outcome, please keep us posted on what your mechanic says. Maybe we'll all learn something from it! And just by the way - in your first post you also mentioned the charge air temperature sensor. It wasn't the problem with my C3, but who knows, cars are mysterious sometimes. If the bottom line is that it costs less to replace the sensors than to repair the engine control unit, that would also be an option. Good luck with the repair, and let us know what comes out!

(Translated from German)

Hi, thanks for the tips and the wise advice! Yes, I will have the fault memory read out and see what the mechanic says. Your advice about the engine control unit and charge air temperature sensor is definitely in the back of my mind. It sounds like I'll probably have to invest quite a bit in the repairs, but what can you do... Cars are indeed mysterious! I'll keep you posted as soon as I have more information. Maybe my problem will help other people too. Thanks again and I hope to have positive news to report soon!

(Translated from German)

I've had a problem for many months, with each mechanic giving me a different version of the problem. So I'm turning to you in the hope that one of you has had the same problem as me (anti-pollution engine light). My wastegate goes down but doesn't come back up I have several fault codes on the case: OBD : - P1351 - P0299 - P1403 ECU : - P0238 - P0299 - P1351 - P1403 Mechanic's version number 1: Turbo solenoid valve out of order. I changed it, still the same problem. Version from mechanic number 2: Turbo to be changed, it's out of order. So I went to another mechanic who told me that my turbo was intact; on the contrary, it was working too much. I went to a trusted mechanic who took all day, but unfortunately he couldn't find the problem. We've changed some sensors, but it's still the same thing. Recently, I went to a mechanic who changed my door and offered to fix the problem for 200€ without me even being able to see where the problem came from. According to him, he prefers not to reveal the problem. So I'm turning to you to find out if I can solve this problem once and for all.

(Translated from French)

Based on the fault codes you've provided, it seems like there could be an issue with the turbocharger or the EGR valve. Fault code P0299 indicates a turbocharger/supercharger underboost condition, and P1403 is related to the EGR system. Before you consider replacing the turbocharger, I'd recommend checking the vacuum lines to the turbo for any leaks or blockages, as these could cause the wastegate issue you're experiencing. Also, inspect the EGR valve and its circuit, as a malfunction here could trigger the P1403 code. Remember, these are just suggestions based on the information you've provided. It's always best to have a professional mechanic diagnose the issue. If the problem is safety-relevant, I highly recommend letting a mechanic check the issue. Please keep us updated on your progress and let us know if you have any further questions.

No mechanic found the problem, so I changed the turbo solenoid valve and the vacuum hose.

(Translated from French)

That's a good start. If the problem persists, you might want to consider checking the EGR valve and its circuit as I mentioned earlier. Also, it might be worth having the fault codes cleared and then see if they return. If they do, it could help pinpoint the exact issue. Please keep us updated on your progress and let us know if you have any further questions.