1999 Volvo s70 Possible MAF sensor issues

[dcmatos]

Careful VAT ( visual, audible, tactile) inspection.

A smoke tester is the definitive way to find it.

Your EVAP stuff is in front of the right rear wheel, btw. Don't let the 1998 location fool you.

I did find a leak. It was in the vacuum tree. One of the caps on the vacuum tree came off. I think that may be what caused the EVAP code on bank 1 and bank 2. I checked the EVAP canister in front of the right rear wheel and I did not find anything wrong with the hoses. I also took a look at the MAF and it was clean.

[FLXC90]

I had my MAF sensor replaced about 5 months ago because it was reading too rich and would not pass an inspection. It worked fine afterwards. I changed out my battery a week ago because the battery went dead after sitting for 4 months without running. I thought it was the fuel pump but a few codes came up when it was diagnosed at Autozone:

p0440
p0171
p0174

It may be possible that my MAF sensor is faulty, but I think there is a strong possibility that my 02 sensor is bad. I'm going to try to clean my MAF sensor first before jumping to the o2 sensor, since it is reading lean and it is cheap. I need a little advice/help if possible.

First things first...do you know these are new codes? or maybe they were stored before the battery died? (does OBD-I do that like II does?)

[abscate]

The P0440 can easily cause the other two codes. Clear them and see what comes back first.