Circuit/System Testing
WARNING: This page does not describe the selected car, but rather 8 other vehicles, including the 2008 GMC Yukon XL, 2008 GMC Yukon, 2008 Chevrolet Tahoe, 2008 Chevrolet Suburban, and 2008 Chevrolet Avalanche. However, it is still accessible from the selected car via links, so may be relevant.
- Verify that there are no air leaks in the system.
- If a leak is found, repair or replace the leaking component as necessary.
- Ignition OFF, remove the ESC/ALC EXH Fuse in the underhood fuse block.
- Disconnect the air pressure sensor and test for less than 2.0 ohms of resistance between the low reference terminal F at the harness connector and ground.
- If greater than specified, test the low reference circuit for open/high resistance. If the circuit tests normal, replace the electronic suspension control module.
- Ignition ON, verify that 4.75-5.25 volts exists between the 5 volt reference circuit terminal A of the harness connector and ground.
- If less that the specified range, test the 5 volt reference circuit for open/high resistance or a short to ground. If the circuit tests normal, replace the electronic suspension control module.
- If greater that the specified range, test the 5 volt reference circuit for a short to voltage. If the circuit tests normal, replace the electronic suspension control module.
- Ignition OFF, disconnect the electronic suspension control module connector.
- Test the pressure sensor signal circuit for a short to ground, open/high resistance, or short to voltage.
- If all circuits test normal, test or replace the automatic level control compressor assembly.