I own a 1996 850 GLT non-turbo. It is a great car. Recently, I was obligated to have a smog check performed here in California. Unfortunately, the 850 just barely failed the NOx level while easily passing the HC and CO2 levels. I brought the car into a state-certified emissions repair center to diagnose and fix the NOx problem. After a good deal of diagnostic work, they were unable to find the problem. The O2 sensor, the three-way CAT and the computer were all fine. The shop contacted the local Volvo dealer for help however, they told me that Volvo refused to provide any advise... Meanwhile, I am left with a car that has not passed the smog test and no one who can diagnose the problem. If I bring the car into Volvo for repair, the state will not help fund the repair whereas, if I use an approved shop, they will.

Has anyone had any problems with NOx on a '96 850? If so, perhaps you could advise me what the problem may be?

Many thanks,

OnlyVolvo