Circuit/System Testing
- Ignition OFF, disconnect the EC ignition relay.
- Ignition ON, test for battery voltage between the ignition 1 voltage circuit of the EC ignition relay and ground.
- If less than B+, repair the ignition 1 voltage circuit of the EC ignition relay for a short to ground or an open/high resistance.
- Test for battery voltage between the B+ voltage circuit of the EC ignition relay and ground.
- If less than B+, repair the B+ voltage circuit of the EC ignition relay for a short to ground or an open/high resistance.
- With the ignition OFF, connect a test lamp between the control circuit and the ignition 1 voltage circuit of the EC ignition relay.
- With the ignition ON, use a scan tool to command the EC ignition relay ON. The test lamp should turn ON for about 3-5 seconds and then turn OFF.
- If the test lamp remains ON all the time, test for a short to ground on the control circuit. If the circuit/connections test normal, replace the ECM.
- If the test lamp remains OFF all the time, test for a short to voltage or an open/high resistance on the control circuit. If circuit/connections test normal, replace the ECM.
- Connect a 15-amp fused jumper wire between the B+ supply voltage circuit and the ignition 1 voltage circuit of the EC ignition relay.
- Attempt to start the engine. The engine should start.
- If the engine does not start, test the ignition 1 voltage circuit between the EC ignition relay and the ECM for a short to ground or for an open/high resistance. If the circuit/connections test normal, replace the ECM.
- If all circuits/connections test normal, test or replace the EC ignition relay.
IMPORTANT:
The ignition 1 voltage circuit is between the EC ignition relay and the ECM. The ignition 1 voltage is a feedback circuit.