94' Buick Lesabre PCM wires cut, why?

After removing the PCM we found that there were two wires on the Red connector that goes into the PCM had been cut from the connector and then crimped together, they were next to eachother (Brown and Red). My question is either what do those wires do, or why would somebody do that?:uhoh: Thx.

This is probably the old trick used to eliminate the check engine light (CEL). Many unscrupulous used car dealers and repair shops will cut these wires to make the CEL disappear so they can charge for repairs not made, or to sell the car without fixing the problem. If you don’t see the CEL illuminated, you think you have an acceptable repair, or you have purchased trouble free car!

BTW, I don't have a 94 LeSabre specific wiring diagram, but IIRC, the brown wire is for the ECM ground to the CEL and the pink wire is power feed. Maybe someone with a 94 LeSabre schematic will key in to tell us exactly what these wires are used for.

Thanks for the reply, unfortunatly the CEL light is one of the reasons why we had to look at the PCM to begin with.

Well it is good that you have "seen the light".:lol: BTW, what are the codes? Why do you suspect a bad ECM/PCM?

Wow, thats a big can of worms youve opened. runaround We've gotten P0361, P0321 and P1321. And I know what youre gonna say, "why would that make me want to look at the PCM?" well, we've replaced the: crank sensor, Cam sensor, IAC valve, all 3 coil packs, spark plugs, spark plug wires, had the fuel pressure checked and had the ICM checked so many times that the Auto Zone guys are sick of us (all in the last month or so) a year ago the PCM was replaced (thats when we originally heard about the possibility of wires being snipped), whats worse is that ALL of these things including the PCM had been replaced 3 years ago. The car was purchased new by my grandfather and was passed down to me.

Anyways, after replacing everything this month we decided to check out the PCM because the car wouldnt start at all. We uncrimped the wires and attached them to where they were SUPPOSED to be, then the car started. (coincidence?? i dunno?) but it still runs like crap and starts only when it feels like. So we figure theres a ground somewhere or a wiring problem to deal with. Mabey replace the Knock sensor? I dunno, we're pulling at staws here. Oh and did I mention that the horn doesnt work, the radio works but doesnt tune into any stations, the ABS light is ALWAYS on (with no ABS problem) and the fuel gadge goes wacky when lower than a half a tank (sediment?) All those things were like that when I got it a year ago. Any thoughts just incase the knock sensor or the wiring doesnt fix the problem (w/ the exception of lighting the thing on fire and cooking marshmallows over it?):banghead: :grinyes:

I would hold off on the "marshmallow roast" for the time being! The longevity of a PCM has no set parameters. A newly installed one can fail, if voltage spikes or erroneous voltages occur. I have seen them fail within a few days of replacement. The knock sensor should have nothing to do with this. Wiring problem would be a possibility, however, this sounds more like a grounded sensor. Have you checked all the sensors for PCM reference voltage (5.0v input) and sensor output voltage? Do you have access to a live data scanner?

Planning on checking the grounds this weekend (wish me luck):rofl:

Don't feel bad, Boeing and NASA had the same problem with finding cut wires.

where would I be able to find a new/used wiring harness that goes to that red pcm connector? Would it be called the 8 way ignition jumper harness? Is that what could also be causing the horn, radio and fuel gauge problem? *brain fried* :eek: Perhaps the mechanic didn't put the Crank sensor in correctly? It seems like A LOT of people on here have similar problems.....