Circuit/System Verification

Ignition ON, verify that no ignition, starter relay, brake pedal position sensor, theft deterrent, engine, or automatic transmission DTCs are set that would cause the ECM to disable engine starting.
- If DTCs are set, refer to Diagnostic Trouble Code (DTC) List - Vehicle .
Ignition ON, observe the scan tool BCM 5 V Ignition Switch (vehicles without push button start) or ECM Power Mode (vehicles with push button start) parameter. Place the ignition switch in the crank position, the parameter should display Crank Request.
- If not the specified value, refer to Power Mode Mismatch .
Transmission in park, verify the scan tool TCM Internal Mode Switch parameter displays Park.
- If the TCM Internal Mode Switch parameter does not indicate Park. Refer to Transmission Internal Mode Switch Logic .
Transmission range selector in park or neutral attempt to start the vehicle. The crank relay should click and the engine should begin cranking.
- If the starter relay does not click or the engine does not crank, refer to Circuit/System Testing.
Ignition ON, observe the scan tool ECM Crankshaft Position Sensor Active Counter is not incrementing.
- If the Crankshaft Position Sensor Active Counter is incrementing, replace the Crankshaft Position Sensor.