ArGuy71

I've got a 2002 GC Laredo 4.7 that sat for a year without a battery.

After installing a new battery, neither of the original keys are recognised. I get the key with a slash symbol through it.

I checked and cleaned the ground going to the PCM. no help.

I replaced the PCM along with a matching programmed key and ignition, now that key is also not recognised.

stumped.

shooptube

I am thinking the skim module that reads the key has an issue.

ArGuy71

Is the skim module what is pictured below, tied to the PCM, along with the key/ignition?



this is what I bought.

ArGuy71

I'd like to find someone who has a good knowledge of this system.

wanting to know if sitting without a battery for a year could make it forget the original keys.

I read about (and did) reseting the PCM "adaptive memory", are there other kinds of memory that can be reset?

This security feature appears to be optional equipment, would a PCM from a GC that wasn't equipped with the sentry feature basically bypass it? I'd rather not have this feature anyway.

If that's possible, can either of the PCM's I have now be re-programmed back to the start, without the sentry optional equipment, while removing all hardware associated with the system?

shooptube

In order to remove factory skim you need a non skim PCM from same year vehicle with same engine. Unplug skim module in steering column. Then plug in new PCM. IF YOU PLUG IN NEW PCM BEFORE REMOVING SKIM MODULE, THAT PCM WILL BE SKIM LOCKED AND NOT USEFUL ANYMORE. It's pretty easy to remove skim

ArGuy71

thanks,

just to confirm, that is the "skim module" your talking about in my picture?, tied to the side of the PCM?

shooptube

Yup. Has a little ring that surrounds the lock cylinder.

ArGuy71

so back to the original problem.

I've got two sets now of what's pictured above.

a PCM with a key that supposed to be programmed to it, and a skim module.

the original set and the one I bought., and both show key with slash.

is there anything else in the circuit?, how many grounding spots? I've just cleaned the one by the fuel rail that hooks to the PCM ground.

it's a new battery but perhaps a bit drained from all the attempted starts and no runs, charging it overnight.

I guess I can throw in the wiring from the skim to the PCM as a possible suspect.

Is there any other stupid feature involving door locks or any other part of the security system I could be overlooking causing this?

ArGuy71

bump for help

dave1123

I'm not certain, but I think the BCM gets involved here.

ArGuy71

body control module? where's that located and does is go out often?

dave1123

Okay, I just read about 4 pages of my FSM on the SKIM module and system. It seems the SKIM communicates with the PCM and BOTH have to be programmed with a DRB III scan tool at the dealer if either one is changed. The dash instrument cluster and the BCM only get involved to turn on the indicator light and audible chime. It seems there is a "secret security code" in the SKIM that has to match the one in the PCM or nothing works. That's why it has to be programmed by the dealer. It's all a conspiracy anyway! SO, it looks like it has to be towed to the dealer. Sucks.

I'd put the original one back in and return the other one. Then get it programmed.

ArGuy71

much appreciated.

so I am to surmise the PCM I bought was not programmed with the skim even though sold as a set?

I have not even put a scan tool to it yet. I have one ordered .

would any error codes I have not cleared, through a basic scan tool, be causing this?

If I have to rely on the dealer's DRBIII, can they not do it out of the vehichle? (no need to tow)''

thanks again.

dave1123

I really don't know but I doubt it. I'm not that computer savy. I just read a lot!

ArGuy71

One thing I've discovered is when the system sees an invalid key, the key slash symbol flashes rapidly.

And that is NOT what I normally get. normally I get the key slash symbol lighting steadily.

The one time I had the old key/ignition/Skim in with the new PCM, the symbol flashed rapidly.

with either of the matched sets (PCM/key/Skim) it lights steadily.

So it appears the system DOES NOT see the key as invalid, but I still get a key slash symbol.