Hi folks,

I'm trying to help my girlfriend out with her 2012 Volvo S60. It's an automatic, and it has a 2.5 liter motor. The car has just about 100k miles, and I'm guessing that she's taken decent care of it (oil changes, etc.). I'm fairly handy around the garage, but I've torn into Audis and Hondas, but never Volvos, so I'm looking for some hints on this one....

Apparently, the CEL has been going on and off lately. The last time I rode in her car, I also noticed a slow-ish knocking sound coming from the motor, but only when the car was accelerating. I have a fairly generic OBD code reader, so I stuck it on there, and am posting a pic of the code that I found. (At the time I pulled the code, the CEL light was NOT on) The code read:
"P000B (Generic)
B Camshaft Position Slow Response Bank 1"
Any guesses where to start on this one? I PROMISE I've been using the search mode around this site, but I haven't found a specific mention of this code and/or knocking sound. It sure sounds like I might start with whatever type of camshaft sensor this motor has, but I could certainly use some more advice. Meanwhile I'm going to keep searching this site.

Any thoughts out there?

 

The cam position sensors rarely go bad - so that would not be a good choice to simply replace it thinking it might be bad. Usually when you get a cam sensor code - it's stored because the cam is in the wrong place at the wrong time. A variable cam timing problem or a cam belt put on incorrectly would be two possibilities.

Don't know about generic scanners but with the factory scan tool you can monitor exactly what the cams are doing. And test various components that might be causing the problem.

 

Thank you for the advice! To say the least, I still have more research to do, about how this VVT system operates. Typically, I'm one of those guys who will sometimes take a stab at the simple fixes - such as sensors, especially if they are inexpensive and easy to swap out. I like the quality of parts that I've gotten from Rock Auto in the past. It appears I can get another camshaft sensor, crankshaft sensor, and a VVT actuator, all for under $100 total. So that is a bit enticing. (Although it sounds that replacing VVT parts might be a bit complicated and/or need a special tool or two.

THAT SAID, I like where you're headed with this. A quick search says that the old timing belt needs replacement by now anyway (and I'm assuming it hasn't been done). The belt clearly hasn't let go, but I guess it is possible that it jumped a tooth. That might also explain why there seems to be knocking during acceleration. I'm guessing that me trying to diagnose VVT/timing belt issues is a little above my pay grade, so....

I think I'll stick your advice. It sounds like my best move is to take it to a decent Volvo shop that has an actual Volvo OBD reader to see everything that the computer has to say, and let them diagnose/inspect diagnose the situation, and then I can decide how to proceed.

Thanks again for the advice! I will report back with an update when I have one.

 

Well, I really don't have much of an update about the sensor. My girlfriend took her car into the Volvo shop, and I spoke with mechanics before she dropped it off, but didn't get the chance to hear the details of the outcome. My girlfriend was supposed to write down specifically what they found, but all she got down was something about "the modules not programming"... So they charged her a total of $300 for the diagnosis and whatever they fixed, and sent her on her way. I'm guessing that it had to be something like a bad sensor, or maybe even just some sort of specific Volvo OBD thing. I'm fairly sure they didn't get into the engine at all, or they would have found a way to charge her more.

Apparently, this Volvo place is fairly well liked, and they also quoted her $650 to do a timing belt job, which sounded surprisingly reasonable from what I was expecting. So I think I'm done worrying about this for the time being. Sorry for the lack of better information here, but your input was certainly helpful overall. Thanks again....