Circuit/System Testing
WARNING: This page is about a different car, the 2010 Cadillac STS. However, it is still accessible from the selected car via links, so may be relevant.
- Ignition OFF, disconnect the harness connector at the rear object sensor control module.
- Test for less than 1.0 ohm between the ground circuit terminal 12 and ground.
- If greater than the specified value, test the ground circuit for an open/high resistance.
- Ignition ON, verify that a test lamp illuminates when connected between the ignition voltage circuit terminal 13 and ground.
- If the test lamp does not illuminate, test the ignition voltage circuit for a short to ground or an open/high resistance.
- Ignition ON, transmission in reverse, verify that a test lamp illuminates when connected between the backup lamp supply voltage circuit terminal 15 and ground.
- If the test lamp does not illuminate, test the backup lamp supply voltage circuit for a short to ground or an open/high resistance. If circuit tests normal replace the rear integration module (RIM).
- Start the engine, scan tool installed, with the vehicle drive wheels raised and the vehicle placed in drive or 1st gear. Verify that the speedometer value matches the scan tool Vehicle Speed parameter in the ECM Engine Data List.
- If the speedometer does not match the scan tool Vehicle Speed parameter, test the vehicle speed signal circuit terminal 18 for a short to voltage, a short to ground or an open/high resistance. If the circuit tests normal, replace the engine control module.
- Ignition OFF, connect the harness connector at the rear object sensor control module.
- Disconnect the harness connector at the rear parking assist display.
- Ignition ON, verify a test lamp illuminates between the telltale assembly supply voltage circuit terminal A and ground.
- If the test lamp does not illuminate, test the circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the rear object sensor control module.
- Connect a test lamp one at a time between the 12 volt supply circuit terminal A and the control circuits listed below:
- Left amber LED control circuit terminal B
- Center amber LED control circuit terminal C
- Red LED control circuit terminal D
- Ignition ON, transmission in reverse, place an object less than 0.3 m (11 in) away from the rear bumper. The test lamp should illuminate at each control circuit.
- If the test lamp does not illuminate at any of the control circuits, test the appropriate control circuit for a short to voltage or an open/high resistance. If the circuits test normal, replace the rear object sensor control module.
- If all circuits test normal, test or replace the rear parking assist display.
IMPORTANT:
Before completing the next step refer to Diagnostic Aids to determine the cause of the inhibit. If a cause has been addressed the vehicle must be driven at speed greater than 40 km/h (25 mph).