Limp mode problem once hot - 06 C30 T5

[scot850]

Well it now appears that the issues are not all resolved. Turns out there was another issue that I was not aware of. Apparently before the other issues started with this car, it had reduced catalytic converter P0420 codes occasionally. It had not appeared after the other repairs so all had seemed good, until this week and it suddenly reappeared. No idea what caused his. Typical cause is the bolts loosening off on the turbo to down pipe bolts. But I would hope after the dealer replaced the turbo and gaskets, this issue would have not been caused by loose bolts.

All I can think is the cat is bad. As this issue stared pre-turbo and cylinder head issues, I have no idea. I have suggested the owner talk to the dealer and ask them for advice, which I suggested it to ensure all bolts were tightened, followed by confirmation the cat is bad or not. If it is bad, simple choice, de-cat the car or replace the cat.

Neil.

[scot850]

Well it continues to be a Good News/Bad News and maybe more work needed.

The car has been running fine for about 6 weeks now with one exception. That is the random cat efficiency message. This was there when the car was bought originally so I don't believe related to the other running issues/limp mode issue.

Apparently it comes on and a few days later goes back off. So we are monitoring it.

Neil.

[abscate]

Maybe just a weak rear OXS? Monitor the voltage on the rear sensor. A new cat would suck on the refurbishment budget

[scot850]

Yes it would. I can't recall if the O2 sensors were done on this car or not. Great suggestion though!

Neil.

[precisionguesswork]

Well, threw in the towel and called in reinforcements! I arrange with one of the local dealers to drop the car off yesterday morning for 1 hour of diagnostics.

Naturally the car ran perfectly all the way there and they could not find any issues as like me they found no codes. By the end of the day even the service manager had rolled up his sleeves and had taken the car for a long run and nothing. They asked if they could keep it overnight as he planned to take it for anther run this morning.

Well, I got a message at lunch time it had thrown a code for the MAF going AWOL. So they planned to throw another MAF in. Naturally I could not authorize that on behalf of the owner as the part is well over $600 CDN and more from the local dealers plus taxes and fitting. (Labour rate is $200 + Tax/hr CDN). They laughed when half an hour later, while on the way to a friends I dropped by and left a good used MAF. The question was how could I have one available...........?

So that is now the MAF, ETM, TCV, battery and I'm sure there was something else all gone bad in 2000km? Can't believe that is possible for a car with just over 100k miles.

Anyway, I did not expect to hear from them again as the manager was in a meeting for the afternoon. Well at about 4pm another message. Thanks for the MAF, but now the car has thrown another code for the BCM (Brake control module). They are like me finally getting towards the idea the issue is possibly wiring or in one of the modules. So they asked to hang o to the car over the weekend so they could take another look on Monday!

So, while I can't truly expect them to do all this work for nothing, technically I have still not been asked for more! I did make the point that although the mechanics are experienced, they are all relatively new to Volvo's so it was an ideal learning challenge for diagnostics!

I guess we will see where this goes. I have a used ECM and CEM if needed for cloning purposes. The dealer does not do this but Xemodex do. Price is about $500 each for cloning assuming the donor parts are good. If not they can get over $700 for repairing the originals or for the CEM if they supply a donor it is nearer $900 CDN. Yikes!

In cases like this you can easily understand how a car can be mechanically totaled.

Neil.

Any luck? Might be a grounding issue...

[scot850]

Possibly a grounding error, but I did remove all the engine grounds, clean and refit them. Finally covered them with protectant to prevent future corrosion. The owner is now looking at having the signals checked as the car did have new O2 sensors fitted I'm told. Might be it is just the cat is contaminated or failing. He is throwing a Hail Mary at it in the form of running cat cleaner through the system.

Thanks for the suggestion!

Neil