S70 troubles -- Please help me STAY a Volvo owner!

[abscate]

You've probably still got a vacuum leak that's upsetting fuel trim. It's not glamorous but you have to just hunt it down.

[Matty Moo]

I'm going to wager good money that the mechanic didn't put the harness on the abs module correctly. That's provided nothing else is going on in the system.

It doesn't matter if he's certified by God himself, AAA or his AA sponsor.....the harness is a pain in the ass and only goes on correctly 50% of the time, the rest of the time you have to take the harness off, put it back on then press down on it some more to allow the air to escape past the gasket. There's a piece of paper that came in the box spelling it out, but nobody ever reads it even though it says "Open and read this".

[scot850]

Engineering 101, if all else fails, and the largest hammer you own doesn't fix it, then read the instructions!!

Neil.

[hayesman76]

UPDATE:
I had some things replaced on the car and now the CHECK ENGINE light is finally off. I just picked the car up from the shop yesterday and have only driven it a few miles but will start driving it to and from work soon. I was advised to put some mileage on the car to reset the computer before bringing it in for another smog test. The SERVICE light came on but went off after a few minutes. I'm not sure but I think the car can still pass the California Smog Test even if the SERVICE light is on, it may be just the CHECK ENGINE light that needs to be off to pass the smog test.

I appreciate all the replies above. I did a good bit of online research about the car's problems and trying to get the CHECK ENGINE light off so that it could pass smog (the car actually passed the emissions part of the smog test, the CHECK ENGINE light being on was the only thing preventing it from passing! grrrrrr!) and had a few parts replaced, things that I saw mentioned by others in the past that other Volvo owners found cured the CHECK ENGINE light issue.

In order to hopefully help any other Volvo owners whose car might be plagued with that issue, here are the things that were done to my car that finally got the CHECK ENGINE light to turn off:

* replace main vacuum tee
* replace vacuum line
* replace air intake boot
* replace mass air flow sensor
* replace O2 sensor
* remove and replace intake manifold gasket

Hopefully the car will now be able to FINALLY pass the dreaded California smog test!

[abscate]

The service light is just a clocked reminder light and isn't part of the emissions protocol.

You just can't fix these cars by. "Symptom troubleshooting" unless you don't mind paying for a bunch of parts you don't need. They are too complex to troubleshoot this way, as are all cars past about 1995

Your intake manifold leak might have been the only thing wrong but will generate huge array of codes for OXS, MAF, etc...