Circuit/System Testing
WARNING: This page does not describe the selected car, but rather 7 other vehicles, including the 2008 GMC Yukon XL, 2008 GMC Yukon, 2008 Chevrolet Tahoe, 2008 Chevrolet Suburban, and 2008 Cadillac Escalade EXT. However, it is still accessible from the selected car via links, so may be relevant.
- Ignition OFF, transmission in Park or Neutral, disconnect the transmission 16-way connector.
- Test for less than 1 ohm of resistance between the Park/Neutral signal circuit terminal 3 on the transmission side and the ground circuit terminal 5.
- If greater than the specified range, test the signal circuit inside the transmission for an open/high resistance. If the circuit tests normal, test or replace the IMS.
- Ignition On, verify the scan tool parameter Park/Neutral displays In-gear.
- If not the specified value, test the signal circuit for a short to ground. If the circuit tests normal, replace the ECM.
- Install a fused jumper between the signal circuit and ground. Verify the scan tool parameter Park/Neutral displays Park/Neutral.
- If not the specified value, test the signal circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the ECM.