Seeking Advice for Black Exhaust Smoke, Engine Light, Power Drop, and Exhaust Leak in 2000 Volvo C70

Hey there, I've got a 1998 Volvo S70 which had a pretty similar issue, so our cases are almost twins! First off, I'm just an average car owner—definitely no Tony Stark of engineering here, so we're talking some experience but more along the lines of good ol' trial and error. I noticed the same symptoms: reduced power, nasty car perfume aka exhaust leaks, and that pesky engine light that stayed lit like an overzealous Christmas tree. Quickly hoofed it to my local workshop, and we found out it was one of the lambda sensors that had gone rogue. That could explain your black smoke, as the faulty sensor was feeding misleading info to the car's engine management system, messing up the fuel/air mix. Fixing it set me back by about 375 Euro (bit of a pinch!). It's not a guaranteed solution for your issue, but definitely worth checking out just to be on the safe side. Do you happen to know what engine model you got in there? That would help zero in more closely on what troubles your faithful beast might be having.

(Translated from German)

Hey, thanks for that recommendation! Tony Stark or not, you surely managed to light a bulb for me. Regarding the engine model, it's a B5234T3, typical of the 2000 C70. Can’t believe I forgot to mention that in the first go. The mileage is 62,679 KM (should've probably gotten a service sachet at the earlier service). I’ll definitely have a look at that lambda sensor, probably will spare my wallet the 375 Euro if the sensor is in fact the culprit. Really appreciate the insight! It's always easier when tackling these sorts of issues with a little help. Thanks! Formally Tony-Stark-less car owner now enlightened.

(Translated from German)

You're very welcome! I'm just glad that my experience could throw a little light on your problem. And believe me, troubleshooting these type of gremlins in the system can really turn you into a Tony Stark! Now with the B5234T3 engine, you have three lambda sensors. One of them is nestled right before the turbo, the second one below the turbo, and the third one— the guy that gave me trouble— is located after the catalytic converter. So, you'd also want to check the functionality of these as they could be hacked off due to the exhaust leak or causing it in the first place. Sounds like you've got a pretty low mileage for a 2000 C70 there, but as we both know, sensors and rubbery bits don't really care about the mileage. They just tend to give up when they feel like it. Anyway, good on you for taking the reins. Let me know what you find – hope it’s just a sensor and not some aftertreatment chaos. Cheers!

(Translated from German)

Massive thanks for the extra tips, I can't tell you how much a difference that makes. I'll see if I can get a check on the other sensors too, just to be extra sure. And yea, they surely have a life of their own, don't they? I'll dig in this weekend and let you know how it all goes. Hoping, just like you, that it’s the sensors throwing a fit and not something major. Fingers crossed! Thanks again, cheers!

(Translated from German)