My 2004 XC70 failed a DEQ test because it is throwing a fault code for a stuck throttle body valve. My Volvo has been running fine for the last five years, could this be a sensor problem, or? (DEQ is the Department of Environmental Quality, can't put new tags on it until I pass the test, emissions were not even tested, they won't test the emissions if the car has ANY fault code)
Looking for any advice on how to determine if this is a real problem, or is just a sensor issue.

 

OK - Have you read/recorded and cleared codes and determined if they come back? What codes are/were stored?

 

Yes, I had a volvo repair shop clear the code (how do they do this?), then immediately returned to DEQ and they wouldn't test my car until I had completed a Volvo engine re-start routine, by driving at least 30 miles and doing a specific way of accelerating. Took about a week of driving until the re-set was completed. At that point, the fault code reappeared. The car is driving and accelerating perfectly. Based on the throttle body problem Posts in this forum it doesn't appear to be a throttle body issue. This was a while back, I have been driving it for months without any problems. I don't remember the code off the top of my head, except it was a P-code, something P2303, P3203.

 

A code is cleared by reading them then pressing the clear/erase button on the scan tool.

Your car has to complete a "drive cycle" where it runs tests on many components and if they all pass no codes are set and your check engine light stays off. To get an emission inspection the state scanner plugs into your car and verifies the drive cycle has been completed.

A common problem with ~2004 throttle is the wiring harness - a bad connection develops at the throttle module. Volvo has a repair kit for that problem. Either a a complete harness as below or individual wires that can be spliced in.

I AM NOT saying that is what your problem is - that will be up to someone actually working on your car. I'm just offering insight into a known throttle problem that I thought was first seen in 2004 year model.