My check engine light came on and I had them run the diagnostic on it at AutoZone. It came back with two codes: P0174 and P0171. This is what it says on the print out:

Fuel trim bank one condition:
The powertrain control module uses the oxygen sensor to calculate the Air/Fuel ratio of the engine. The computer has recognized a rich or lean condition on one engine bank only.
Probable cause:
- If bank one and two codes are set together suspect fuel pressure or MAF (Mass Air Flow) sensor
- Oxygen sensor defective
- Ignition misfire-repair
- Fuel injector problem

Fuel trim bank two condition:
The ECM has detected a rich or lean Air/Fuel ratio condition on engine bank two
Probable cause:
- If bank one and two are set together suspect a fuel pressure condition or MAF sensor fault
- Failed H02S21 (Heated oxygen sensor - Bank 2 Sensor 1)
- Ignition misfire condition
- Fuel injector problem
- Engine mechanical condition


To the idiot here, it sounds like a "fuel pressure condition or MAF sensor fault" since it gave both of those codes. Is that correct, and if so what should I do now?

TIA

bagger05

I am NOT a mechanic.... Just a gal who called her dad last week for the same problem (engine light came on, codes suggested O2 sensor and/or coolant). Based on dealing with my car and his old work car (both Saturns) in the past, he told me to put a bottle of Seafoam in the tank, fill it with premium and see if that helped. After driving 100 miles, the light went off.

I filled up last week at a different station than I normally do. Not sure if I got some bad gas or what, but everything seems to be fine now.

I just found this:

http://www.automotiveforums.com/vbulletin/showthread.php?t=768631

Sounds like it might be the issue, but I'm definitely going to try putting some of that fuel injector cleaning stuff and a tank of premium into it before I spend any real money or start tinkering around under the hood.

Thanks for the advice.

How many miles? O2 sensor is not a really hard thing to change. At least it wasn't on my truck. and they are not that expensive. I would do the fuel injector thing first. Then try the next least expensive fix which is probably the O2 sensor. Certain pollution control devices can go bad and give you signals that tell you to replace something that doesn't need it.

On my truck the O2 sensor wasn't the problem like the computer said. It was my EGR valve stuck in the open position that would cause the light at idle. Once i got moving it went off. Not saying this is your problem but sometimes it not an easy fix.

~108k miles

Some of those sensor will get corroded at high miles. It is located in the exhaust pipe and if you have water or a lot of condensation coming out of your tail pipe that can ware them out. I would still go with the injector cleaner and then if that doesn't work try the O2 sensor.

Is this a Vulcan 3.0L or a Duratec 3.0L?

(12V or 24V)?