Tom,

You need to check if you have +12 power on GM ECM harness pin A6 in both crank and run. This pin provides power to the MS. A good place to check power on the Ms itself is the voltage regulator. If you hold the board so the heat sink is facing up the input pin to the reg. is the LH one.

Check the Harness pin then check the regulator pin in both crank and run.

Pin A6 is on the smaller of the 2 GM connectors top row. The numbers are embossed into the connector plastic.

EFI

Last edited by efi-diy; 05/10/10 10:33 PM.
51 GMC 4.2 turbo
Can't solved today's problems using the same technology/thinking that created them