Hi All,

here are 2 major tricks I've found when flashing the E38 PCM. Please note that these are for the Holden based cars and may not work on others......


  1. For VZ based vehicles, you can access the PCM with the ignition set to "accessory" rather than run ( reds on ). Both reads and writes to the PCM are available. Flashing the PCM in this mode gives a clean write with no dash warnings or errors during or after the flash.
  2. In some ( if not all ) VE based vehicles, you can write to the PCM with the ignition "OFF", but to read it you need to have the ignition set to at least accessories. Flashing the PCM with the ignition off was a surprise to me. I didn't realise I'd done it till I went to turn the ignition off and it already was. To confirm the write, I read the same tune back out and compared it to the tune I was trying to write, both matched. When I did the flash with the ignition off, I got no warnings or errors during or after the flash process.