Chart C-1A, Electrical Load Idle-Up Signal Check: Notes
Engine Control Module (ECM) receives an idle-up signal from diode module. This signal is present whenever one or more of the following systems is turned on or operated:
- Headlights.
- Rear window defogger.
- Brakelights.
- Heater blower motor.
- Radiator cooling fan.
Engine RPM will slightly increase for the additional electrical load.
NOTE:
Test numbers refer to numbers on diagnostic chart.
- Checks for electrical load signal to ECM.
- Checks for open circuit to ECM, or a faulty ECM, or a faulty diode module.