Circuit/System Testing

Ignition OFF and all vehicle systems OFF, disconnect the KR27C Starter Pinion Solenoid Actuator Relay. It may take up to 2 min for all vehicle systems to power down.
Test for less than 10 Ω between the ground circuit terminal 2 and ground.
- If 10 Ω or greater
1. Ignition OFF.
2. 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.
- Go to next step: If less than 10 Ω
Ignition ON.
Verify a test lamp illuminates between the B+ circuit terminal 3 and ground.
- If the test lamp does not illuminate and the circuit fuse is good
1. Ignition OFF.
2. 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 good and there is voltage at the fuse.
- If the test lamp does not illuminate and the circuit fuse is open
1. Ignition OFF.
2. Test for infinite resistance between the B+ circuit and ground.
  - If less than infinite resistance, repair the short to ground on the circuit.
  - Go to next step: If infinite resistance,
3. Test for infinite resistance between the control circuit terminal 5 and ground.
  - If less than infinite resistance, repair the short to ground on the circuit.
  - If infinite resistance, replace the M64 Starter Motor.
- Go to next step: If the test lamp illuminates
Connect a test lamp between the control circuit terminal 1 and the ground circuit terminal 2.
NOTE:
If the Starter Pinion Relay command is not available in the scan tool, verify the test lamps turns on and off when cycling the ignition between the OFF and CRANK position with the parking brake set and clutch pedal pressed (manual transmission) or the transmission in Park (automatic transmission).
Verify the test lamp turns ON and OFF when commanding the Starter Pinion Relay ON and OFF with a scan tool.
- If the test lamp is always OFF
1. Ignition OFF, disconnect the X1 harness connector at the K20 Engine Control Module.
2. Test for infinite resistance between the control circuit and ground.
  - If less than infinite resistance, repair the short to ground on the circuit.
  - Go to next step: If infinite resistance
3. 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
1. Ignition OFF, disconnect the X1 harness connector at the K20 Engine Control Module, ignition ON.
2. 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.
- Go to next step: If the test lamp turns ON and OFF
Ignition ON, connect a 30 A fused jumper wire between the B+ circuit terminal 3 and the control circuit terminal 5.
Verify the M64 Starter Motor is activated.
- If the M64 Starter Motor does not activate
1. Ignition OFF, disconnect the harness connector at the M64 Starter Motor.
2. Test for infinite resistance between the control circuit terminal X1 2 or X B and ground.
  - If less than infinite resistance, repair the short to ground on the circuit.
  - Go to next step: If infinite resistance
3. 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.
- Go to next step: If the M64 Starter Motor activates
Test or replace the KR27C Starter Pinion Solenoid Actuator Relay.