Circuit/System Testing
WARNING: This page does not describe the selected car, but rather 8 other vehicles, including the 2012 GMC Yukon XL, 2012 GMC Yukon, 2012 Chevrolet Tahoe, 2012 Chevrolet Suburban, and 2012 Chevrolet Avalanche. However, it is still accessible from the selected car via links, so may be relevant.
NOTE:
These diagnostics are based on having no trailer connected.
- Ignition ON, verify that DTC P2534 is not set.
- If the DTC is set, refer to DTC P2534 .
- Ignition OFF, disconnect the harness connector at the trailer brake controller switch.
- Test for less than 5 Ω between the low reference circuit terminal 8 and ground.
- If greater than the specified range, test the low reference circuit for an open/high resistance. If the circuit tests normal, replace the fuel pump/trailer brake control module.
- Ignition ON, test for 4.8-5.2 V between the 5 V reference circuit terminal 3 and ground.
- If less than the specified range, test the 5 V reference circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the fuel pump/trailer brake control module.
- If greater than the specified range, test the 5 V reference circuit for a short to voltage. If the circuit tests normal, replace the fuel pump/trailer brake control module.
- Verify the scan tool Manual Apply Switch parameter is less than 5 percent.
- If greater than the specified range, test the signal circuit terminal 4 for a short to voltage. If the circuit tests normal, replace the fuel pump/trailer brake control module.
- Install a 3 A fused jumper wire between the signal circuit terminal 4 and the 5 V reference circuit terminal 3. Verify the scan tool Manual Apply Switch parameter is greater than 90 percent.
- If less than the specified range, test the signal circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the fuel pump/trailer brake control module.
- Verify the scan tool Redundant Manual Apply Switch parameter is greater than 90 percent.
- If less than the specified range, test the signal circuit terminal 5 for a short to voltage. If the circuit tests normal, replace the fuel pump/trailer brake control module.
- Install a 3 A fused jumper wire between the signal circuit terminal 5 and the 5 V reference circuit terminal 3. Verify the scan tool Redundant Manual Apply Switch parameter is less than 2 percent.
- If greater than the specified range, test the signal circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the fuel pump/trailer brake control module.
- Ignition ON, test for 4.8-5.2 V between the signal circuit terminal 6 and ground.
- If less than the specified range, test the signal circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the fuel pump/trailer brake control module.
- If greater than the specified range, test the signal circuit for a short to voltage. If the circuit tests normal, replace the fuel pump/trailer brake control module.
- If all circuits test normal, test or replace the trailer brake controller switch panel.