Circuit/System Testing
- Ignition ON, measure the voltage at the battery terminals and compare it with the scan tool ECM Ignition 1 Signal parameter. Verify that battery terminal and ignition 1 signal readings do not differ more than 1.0 volt.
- If greater than specified value, test the ignition 1 and ground circuits for open/high resistance. If the circuits test normal, replace the ECM.
- Go to CHARGING SYSTEM TEST .