Dump the flash from your 32 bit GM PCM.

This article describes how to make a simple modification to your 68332 based GM computer to allow you to dump and reprogram the flash. It operates using the BDM port that is built into every Motorola 68332 processor. The BDM port is normally used during software development to allow the programmer to single step through the code, set breakpoints, examine memory, etc. The BDM port has complete access to the CPU and everything connected to it. In this case that means it can read the contents of the flash, and also reprogram it.

This method of dumping and reflashing does not use the DLC (OBD2 connector), and does not require any scan tools or other OEM type hardware. The article is divided into 2 parts.

Nothing in this article, properly implemented, will affect your PCMs operation. However, modifying the flash can leave your PCM (and vehicle) inoperative, or worse. These changes have not been tested in a vehicle, only on a workbench. Please be careful if you decide to make these changes on a PCM used in a vehicle.

Part 1: Modifying your PCM
Part 2: BDM hardware and software
Written by Steve Ravet (steve.ravet@arm.com)