2012 Volvo S40 Experiences Reduced Power, Black Exhaust Smoke, and Unusual Noises: Potential Charge Air Temperature Sensor Issues?

Hey, sorry to hear about your car issues. I had a similar issue with my 2015 Volvo S60, running on gas, with about 168,000 KM on it. The oil light was flashing intermittently, and like you, I had a decrease in power and black clouds belching from the exhaust. The problem turned out to be the engine control unit (ECU). It was, indeed, a pretty serious issue. The ECU is a vital component: it manages your engine's fuel/air mixture, ignition timing, and a whole lot more. In my case, there was a specific fault code that the mechanic traced back to the ECU - something to do with it misreading the data from the Charge air temperature sensor. This was causing the engine to supply the wrong amount of fuel and that's why the performance dropped significantly. So, it's worth having your mechanic do a full diagnostic, explaining your symptoms, and asking for a check on this specific error code. Hope this helps and your baby gets back to full health soon. Cheers.

(Translated from German)

Hey there! Those troubles with your Volvo S60 sound eerily similar to the nightmare I'm currently dealing with my S40. Bummer that you went through that, but hearing about your solution gives me a sense of direction. That error code linked to the ECU could be the missing puzzle piece I'm looking for. What's a bit hard to shake off is the possibility of getting slapped with a hefty repair bill, given how crucial the ECU is. Would you mind sharing how much you shelled out to get it fixed? And have you encountered any related issues since then? Thanks heaps in advance!

(Translated from German)

Hey! Yeah, I hear ya. The whole experience was a real headache, not gonna lie. But let me tell ya, ever since that diagnostic and repair job, my Volvo S60 has been running like a dream. To answer your question, fixing the ECU, or the Evaluation Electronics Defective as they called it, set me back about a grand - 1000€. Stings the wallet a bit, but in the end, the improvement on my ride was more than worth it. And about the Charge air temperature sensor malfunction you mentioned earlier, yeah, that was fixed when they did the ECU repair. There were no extra charges for that. Since the fix-up, I haven't really come across any similar issues. So, I reckon go ahead and check out the ECU on your S40. It might just be the answer you're looking for. Good luck, dude!

(Translated from German)

Hey! That information is gold! Yeah, a grand does make my wallet flinch but if it puts an end to this mechanical mess, it'll surely be worth every cent. I'm relieved to hear that your Volvo S60 is running smoother after the repair job. It gives me hope that my S40 can be brought back to its glory days too. No extra charge for the sensor malfunction fix is a comforting piece of info, seriously, I was bracing for further bad news there. Thanks for chipping in with your experience! I’ll ask the mechanic to specifically check on the ECU and that error code. I'm off to the mechanic tomorrow, fingers crossed. Hoping for the best! Cheers.

(Translated from German)