Thread: Daughter-in-Law's GP 3.8 throwing code

Hi guys, noob here. DIL has a 2004 Grand Prix GTP (supercharged 3800). A few months ago it was throwing a code P0132 if I recall, that indicated one of the O2 sensors was bad, so I replaced the sensor indicated (the upper sensor on the engine side of the cat at the back side of the engine below the firewall. That seemed to solve the issue briefly, but then it came back. We then discovered a cracked exhaust manifold so replaced that with new gaskets - still throwing the code.

At this point, I'm kinds stuck and fishing for ideas. The two things that come to mind are 1) just a dirty connector at the sensor or the PCM, or 2) a bad PCM?

Any of you guys have any ideas of what I might try or check before I invest in a refurb PCM?

Thanks,

Basil

Originally Posted by bandook

I would doubt it's the PCM. Are there any other symptoms? It could be a vac leak or a bad MAF. Could be several things. Basically if anything is making it run too rich or too lean, the O2 sensor will not switch back and forth, high to low voltage, and you will get that code. Might even be bad plugs. Has it had a tune up since she had it?

It does have new plugs and wires but no major tune up. Hadn't thought of possible vac leak or MAF, but I'd have thought if the MAF were bad it would be throwing a code that said so?

Not always a code on the MAF. Also check the fuse for the MAF and make sure it's good and also the wires leading to it as they can get brittle with age and crack/break. If you have to replace the MAF find a good used one in a junkyard that matches. Don't go aftermarket. Stick with the Delco one as there have been issues in the past using other MAF sensors.

Originally Posted by FordMan77

Not always a code on the MAF. Also check the fuse for the MAF and make sure it's good and also the wires leading to it as they can get brittle with age and crack/break. If you have to replace the MAF find a good used one in a junkyard that matches. Don't go aftermarket. Stick with the Delco one as there have been issues in the past using other MAF sensors.

Thanks for the advice on the MAF. Rockauto has remanufactured Delco MAF for $46 with a $28 refundable core charge.