Circuit/System Verification
- Ignition ON.
- Verify that no ignition, KR27 Starter Relay, brake pedal position sensor, theft deterrent, engine, or automatic T12 Transmission DTCs are set that would cause the ECM to disable engine starting.
- If DTCs are set
- If no DTCs are set
- Verify the scan tool BCM 5 V Ignition Switch (vehicles without push button start) or ECM Power Mode (vehicles with push button start) parameter is Crank Request while attempting to start the vehicle.
- If parameter does not display Crank Request
Refer to Vehicle Will Not Change Power Mode
- If parameter displays Crank Request
- If parameter does not display Crank Request
- Verify the scan tool TCM Internal Mode Switch parameter displays Park when in park.
- If the TCM Internal Mode Switch parameter does not indicate Park .
- If the TCM Internal Mode Switch parameter displays Park
- Verify the scan tool ECM Crankshaft Position Active Counter parameter is not incrementing.
- If the counter increments
Replace the B26 Crankshaft Position Sensor.
- If the counter does not increment
- If the counter increments
- Verify the engine cranks in park or neutral.
- If the KR27 Starter Relay does not click or the engine does not crank
Refer to Circuit/System Testing.
- If the engine cranks
- If the KR27 Starter Relay does not click or the engine does not crank
- All OK