Circuit/System Testing
- Ignition OFF and all vehicle systems OFF, disconnect the KR27 Starter Relay. It may take up to 2 minutes for all vehicle systems to power down.
- Test for less than 10 Ω between the ground circuit terminal 86 and ground.
- Ignition OFF.
- Test for less than 2 Ω in the ground circuit end to end.
- If 2 Ω or greater, repair the open/high resistance in the circuit.
- If less than 2 Ω, repair the open/high resistance in the ground connection.
- Ignition ON.
- Verify a test lamp illuminates between the B+ circuit terminal 30 and ground.
- If the test lamp does not illuminate and the circuit fuse is OK
- Ignition OFF.
- Test for less than 2 Ω in the B+ circuit end to end.
- If 2 Ω or greater, repair the open/high resistance in the circuit.
- If less than 2 Ω, verify the fuse is OK and there is voltage at the fuse.
- If the test lamp does not illuminate and the circuit fuse is open
- Ignition OFF.
- Test for infinite resistance between the B+ circuit and ground.
- If less than infinite resistance, repair the short to ground on the circuit.
- Test for infinite resistance between the control circuit terminal 87 and ground.
- If less than infinite resistance, repair the short to ground on the circuit.
- If infinite resistance, replace the KR27 Starter Relay.
- If the test lamp illuminates
- Connect a test lamp between the control circuit terminal 85 and the ground circuit terminal 86.
- Verify the test lamp turns ON and OFF when commanding the starter relay ON and OFF with a scan tool.
- If the test lamp is always OFF
- Ignition OFF, disconnect the harness connector at the K20 Engine Control Module.
- Test for infinite resistance between the control circuit and ground.
- If less than infinite resistance, repair the short to ground on the circuit.
- Test for less than 2 Ω in the control circuit end to end.
- If 2 Ω or greater, repair the open/high resistance in the circuit.
- If less than 2 Ω, replace the K20 Engine Control Module.
- If the test lamp is always ON
- Ignition OFF, disconnect the harness connector at the K20 Engine Control Module, ignition ON.
- Test for less than 1 V between the control circuit and ground.
- If 1 V or greater, repair the short to voltage on the circuit.
- If less than 1 V, replace the K20 Engine Control Module.
- If the test lamp turns ON and OFF
- Ignition ON, connect a 30 A fused jumper wire between the B+ circuit terminal 30 and the control circuit terminal 87.
- Verify the M64 Starter Motor is activated.
- If the M64 Starter Motor does not activate
- Ignition OFF, disconnect the harness connector at the M64 Starter Motor.
- Test for infinite resistance between the control circuit terminal 1 or A X1 and ground.
- If less than infinite resistance, repair the short to ground on the circuit.
- Test for less than 2 Ω in the control circuit end to end.
- If 2 Ω or greater, repair the open/high resistance in the circuit.
- If less than 2 Ω, replace the M64 Starter Motor.
- If the M64 Starter Motor activates
- Test or replace the KR27 Starter Relay.