So I’ve recently bought a 2013 c30 from my local Volvo dealer, almost a week ago. We took the car for a test drive and the check engine light came on. I did not take possession of the car that day but agreed to purchase as they assured me they will fix it. We get through the weekend, because the service is not open at that time and then comes Monday. They figured it was an O2 sensor and they replace both of them. This apparently did not solve the problem. Now they think the ECM might be bad. Now I’m glad they are catching this before I take it home but for a car that has been on the lot for about two months wouldn’t you figure this would have come up before? Should I be nervous to buy this now and what else should I look out for? The car has 62,000 on it which I thought is low miles for this year. Input please and thank you.

 

a few thoughts. 1) check your local lemon laws for used cars - if they promised to fix the CEL issue and the light returns, its not fixed. 2) CEL lights are just diagnostics on a condition not a direct indicator of the root cause. It would be useful to post up what code was found. For example, an intake air or exhaust leak can throw a code set by the O2 sensor but doesn't mean the sensor is bad. 3) Finally, why would you assume the ECM is bad? They are pretty stout components so if there's a CEL fault code for a communications error, its way more likely to be caused by a connector that needs cleaning or a voltage issue (weak battery say). If you can find out what fault codes were set, that will help give some input on what the range of possible causes are.

 

Will do. Thanks again for being responsive.

 

So it turns out it is a fuel pump problem. They say it is a cycling issue, caused the car to run lean and burnt the O2 sensors out. We’ll see if this is the solution.