Circuit/System Testing

Testing the Ignition 1 Signal Circuit

IMPORTANT: A resistance of 5 ohms or greater in the circuit will cause the DTC to set.
1. Ignition ON, verify that B+ is available to both test points of the fuse from the powertrain relay to the ECM.
   • If B+ is only available on one test point of the fuse, test the ignition 1 voltage circuit from the fuse to the ECM for a short to ground. If the circuit tests normal, replace the ECM.
   • If B+ is not available on either test point of the fuse, replace the underhood fuse block.
2. Ignition OFF, disconnect the ECM C1 connector.
3. Ignition ON, verify that B+ is available at C1-19.
   • If B+ is not available, test the ignition 1 voltage circuit for an open/high resistance conditions. If the circuit tests normal, replace the ECM.
4. If all circuits test normal, replace the ECM.

Testing the EC Ignition Relay Feedback Circuit

IMPORTANT: A resistance of 5 ohms or greater in the circuit will cause the DTC to set.
1. Ignition OFF, remove the powertrain relay from the underhood fuse block.
2. Ignition ON, connect a 3A fused jumper wire from B+ to the powertrain ignition 1 voltage circuit terminal. Verify that the EC Ignition Relay Feedback parameter displays B+ on the scan tool.
   • If the scan tool parameter is less than the specified value, test the ignition 1 voltage circuit for an open/high resistance or short to ground. If the circuit tests normal, replace the ECM.