I'm trying to diagnose a random cutout and some of the system checklists suggest there should be 12V on the + and C terminal of the ICM with the key on and the engine not running. I don't have power on these terminal until the car starts. If there should be power on these terminals with just the key on, what would cause it not to be there? I have a new ICM.

It's an early 1990's TBI with a Painless TBI wiring harness.

 

WHAT VEHICLE???

Possible messed-up wiring/wiring connections that doesn't power the ignition with the key in "Run". Powered with the key turned all the way to "Crank" or "Start".
Or
Possible failing ignition switch.

 

Use a fsm for obs 88-91 the schematic should be 1227747 ecm

 

 

The schematic is fine if this is an original vehicle.

I have this suspicion it's a "'90s TBI" engine (V6? Small-Block? Big Block?) in an earlier vehicle, the "Painless TBI wiring harness" makes me think this isn't an original application, and so the schematic may/may not apply.