'99 silverado PCM

[Dex857]

I have a '99 silverado 4x4 5.3 Z71.

Swapped the PCM with a '01 PCM.. works great but the battery warning light goes on and off. I looked at the wiring diagrams and added the wire from the alt to the PCM but still no joy.

 

Just to be CLEAR... I WANT to use a 01-02 PCM. That is why I put in a 01 PCM. The shifts are WAY better and the driveablity is WAY better. I have an 00 and a 99 PCM as well. You can clearly feel the diiference when you drive it. I have had the 01 in for over 2 years. Just want to get the battery warning issue resolved

 

Does anyone know how to resolve this??

 

 

A little help over here please

 

 

Thanks...

[redvett]

Easiest is to put in the correct PCM. Your dealing with powertrain calibrations and security cals. They must be right to shut off the lights.

[kdm101]

You need to be sure to install a PCM that is of the proper service #.

 

The 99-00 trucks use PCM service # 09354896

 

From what I've found, the 01-02 service # 12200411 should also work. However, depending on the "donor" vehicle, it could have had different optioning than yours. It may eventually settle out, then again, it might not.

 

If you have a dealer that's pretty good about doing things "unofficially", see if they'll get their tech2 tool to reflash the PCM so it talks correctly. Might be a good question for "Ask the GM Tech".