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Home >> GMC >> 2006 >> Sierra 1500 HD, RWD >> Repair and Diagnosis >> External Pages >> Different car >> Section 1593 (Trailer Brake Control System) >> Diagnostic Information and Procedures >> DTC C0880, C0890, C1115, C1116, C1117, or C1118 (Gasoline With LY6, or Diesel) >> Circuit/System Testing

Circuit/System Testing

WARNING: This page is about a different car, the 2010 GMC Sierra, 2010 GMC Cab & Chassis Sierra, 2010 Chevrolet Silverado, and 2010 Chevrolet Cab & Chassis Silverado. 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.
  1. Ignition ON, verify that DTC P2534 is not set.
  2. Ignition OFF, disconnect the harness connector at the trailer brake controller switch.
  3. 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 trailer brake control module.
  4. 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 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 trailer brake control module.
  5. 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 trailer brake control module.
  6. 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 trailer brake control module.
  7. 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 trailer brake control module.
  8. 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 trailer brake control module.
  9. 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 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 trailer brake control module.
  10. If all circuits test normal, test or replace the trailer brake controller switch panel.