Check engine light still on after new O2 sensors

98 grey s70 · Post by **98 grey s70** » 29 Jul 2005, 11:31

I have a 98 Volvo S70 with 237,000 miles and love the car but have been struggling to fix the problem that keeps causing my check engine light to come on and stay on. It gives me a trouble code of P0172 (Fuel Mixture too Rich). I decided to go ahead and change both O2 sensors and reset the check engine light. It stayed off for about a day and now its back on.

I also check for vaccum leaks with a butane gas bottle (by suggestion) to see if it would surge and had no luck. Does anyone have any other suggestions on what I can. I work for an auto warehouse so getting parts is no problem, just need to know what else to change.

Another Guest · Post by **Another Guest** » 29 Jul 2005, 11:53

Air Mass Meter (MAF)

Jot · Post by **Jot** » 30 Jul 2005, 11:36

Be carefull on changing 02 sensors. I have bought sensors that are NOT correct because of incorrect cross reference numbers.Does the car have an air pump? How does the air filter look? Do you have the original Cat? The MAS will usually give a code.

98 grey s70 · Post by **98 grey s70** » 01 Aug 2005, 10:50

Jot wrote:Be carefull on changing 02 sensors. I have bought sensors that are NOT correct because of incorrect cross reference numbers.Does the car have an air pump? How does the air filter look? Do you have the original Cat? The MAS will usually give a code.

The air filter is new. You right on the MAS, my sisters car showed a MAS code. It is probably the original cat.