Flow of Diagnosis

Inspection and Verification
1. Verify the vehicle customer's original concern by operating the shift interlock system to duplicate the condition.
2. Inspect to determine if one of the following mechanical or electrical concerns apply:
Mechanical
1. Shift control linkage binding.
2. Damaged ignition/shifter interlock cable.
3. Damaged shift cable.
Electrical
1. Circuitry open/shorted.
2. Blown fuse.
3. Damaged stoplight switch.
4. Damaged shift lock actuator.
5. Damaged powertrain control module.
6. Burned-out bulb.
3. If the concern(s) remains after the inspection, determine the symptom(s) and go to Diagnosis by Symptom.
Symptom Related Diagnostic Procedures