Excellent thread. I hope you continue posting.

All four of the codes are Long-term fuel trim. Yes a air leak can cause all of them. Any air leak after the MAF sensor can be the cause. If the air leak is on the intake side, you can locate it with starting fluid. With the engine cold, start the engine. Spray starting fluid around the intake, hoses...

If the MVS cross-reference https://www.matthewsvolvosite.com/volvo-1999-and-newer-codes is correct (no reason to suggest it’s not), and you have a portable copy of VIDA available, all the codes map out to a fuel-air mixture problem as RHP alludes above. Highly likely not the airbox (bottom rear of m...

P0190 - ECM-280B: Fuel pressure sensor. P0188 - (ASE): Fuel Temperature (Sensor B) Circuit High ... I don't think Volvo ever used P0188. For the PCV, do the glove test. Tie down the glove so that it does not get sucked into the engine if it passes. Fail: If the glove stands up. Pass: If the glove su...

Figured there was something wrong with the information. I could not find a fuel pressure sensor or a fuel temperature sensor. Replacing a oxygen sensor (HO2S) should be the last resort. Keep looking for leaks in both the intake and exhaust systems. ---------------------------------------------------...

Trying to help out my son's GF with this same repair, so I'm repeating the questions Jewl1215 asked: How DIFFICULT was this purge valve to remove and replace? What tools will I need? After removing all the crap off the top of the engine, can it be accessed easy enough without having to remove the ai...