another member mentioned checking the plugs at the ecu/ecm, how would that be done? car running or not? ohms or volts?
Either ohms or volts.
Voltage measurements on an operating circuit can be more enlightening.Ohms are OK
Pull the ECU plug.
One lead on battery negative,the other on the relevent ground pin.
Resistance should be very low.Maybe 0.1 ohm or so.
You can use the yellow and red "check connectors" near the ECU instead of pulling the plug,but,I would not bother.
Key on.Car running would be desirable.
One lead on battery negative,the other at each check connector ground pin or backprobing the ECU plug.
Voltage should not be more than a tenth or two.I would quickly check for AC voltage while the leads are hooked up.
Check power on pin 24 or the check connector similarly.
Check for good pin engagement while the plug is off.