GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Chevrolet 🢒 2009 🢒 Avalanche - 4WD 🢒 Driver Information and Entertainment 🢒 Cellular, Entertainment, and Navigation 🢒 DTC C0880, C0890, C1115, C1116, C1117, or C1118

Diagnostic Instructions
    • Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure.
    • Review Strategy Based Diagnosis for an overview of the diagnostic approach.
    •  Diagnostic Procedure Instructions provides an overview of each diagnostic category.

DTC Descriptor

DTC C0880 00: Device Voltage Reference Output 2 Circuit

DTC C0890 00: Device Voltage Reference Output 3 Circuit

DTC C1115 08: Manual Trailer Brake Apply Request Switch Signal Invalid

DTC C1115 5A: Manual Trailer Brake Apply Request Switch Signal Plausibility Failure

DTC C1116 00:  Manual Trailer Brake Apply Request Signal 1

DTC C1117 00:  Manual Trailer Brake Apply Request circuit Signal 2

DTC C1118 00: Trailer Brake Control Sensitivity Switch Circuit

DTC C1118 08: Trailer Brake Control Sensitivity Switch Circuit Signal Invalid

Diagnostic Fault Information

Circuit

Short to Ground

Open/High Resistance

Short to Voltage

Signal Performance

5-Volt Reference

C0880 00, C0890 00, C1116 00, C1117 00

C1116 00, C1117 00

C0880 00, C0890 00, C1117 00

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Redundant Manual Apply Signal

C1117 00

C1117 00

C0890 00, C1117 00

C1115 08,C1115 5A

Manual Apply Signal

C1116 00

C1116 00

C0890 00, C1116 00, C1117 00

C1115 08,C1115 5A

User Gain switch Signal

C1118 00

C1118 00

C1118 00

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Low Reference

--

C1116 00, C1117 00, C1118 00

--

--

Circuit/System Description

The TBCM system has a control panel with the trailer gain and manual apply switches, and is located on the instrument panel to the left of the steering column. The control panel and switches allows you to adjust the amount of output, referred to as trailer gain, available to the electric trailer brakes and allows you to manually apply the trailer brakes. The Trailer Brake Control Panel, and switches is used along with the Trailer Brake Display Page on the DIC to adjust and display power output to the trailer brakes.

Conditions for Running the DTC
    • Battery voltage is 9.5 - 17 volts.
    • The module is powered up and completes initialization.

Conditions for Setting the DTC

C0880 00 or C0890 00

The TBCM detects the 5 volt reference circuit voltage is less than 4.8 volts or greater than 5.2 volts.

C1115 08 or C1115 5A

    • The TBCM detects the manual apply switch is applied before the ignition is cycled OFF, and continuously applied for 30 seconds after ignition is cycled to ON.
    • The TBCM detects the manual apply switch is applied continuously for 5 minutes.
    • The fault is detected if the manual apply switch input and redundant apply switch input exceeds a threshold for an extended amount of time.

C1116 00

    • The TBCM detects a short to ground, open or a short to voltage on the manual apply signal circuit.
    • The TBCM detects a open on the low refernece circuit.

C1117 00

    • The TBCM detects a short to ground, open or a short to voltage on the redundant manual apply signal circuit.
    • The TBCM detects a short to voltage on the manual apply signal circuit.
    • The TBCM detects a open on the low refernece circuit.

C1118 00

    • The TBCM detects a short to ground, open or a short to voltage on the user gain signal circuit.
    • The TBCM detects a open on the low refernece circuit.

C1118 08

    • The TBCM detects the user gain switch is applied before the ignition is cycled OFF, and continuously applied for 30 seconds after ignition is cycled to ON.
    • The TBCM detects the user gain switch is applied continuously for 5 minutes.

Action Taken When the DTC Sets
    • The trailer brake control will be disabled for the remainder of the ignition cycle.
    • The driver information center (DIC) will display Service Trailer Brake System.

Condition for Clearing the DTC
    • The condition for the DTC is no longer present.
    • The TBCM clears the history DTC when a current DTC is not detected in 40 consecutive drive cycles.

Reference Information

Schematic Reference

Trailer Brake Control Schematics

Connector End View Reference

Component Connector End Views

Description and Operation

Trailer Brake Controls Description and Operation

Electrical Information Reference

    •  Circuit Testing
    •  Connector Repairs
    •  Testing for Intermittent Conditions and Poor Connections
    •  Wiring Repairs

Scan Tool Reference

Control Module References for scan tool information

Circuit/System Verification

Ignition ON, observe the scan tool trailer brake controls user gain parameter. The reading should be between 0-100 percent, and change with operating the gain switch up or gain switch down.

Circuit/System Testing
  1. Ignition OFF, disconnect the harness connector at the trailer brake controller switch.
  2. Test for less than 5 ohms of resistance between the low reference circuit terminal 8 and ground.
    3. ⇒If greater than the specified range, test the low reference circuit for an open/high resistance. If the circuit tests normal, replace the TBCM.
  3. Ignition ON, test for 4.8 - 5.2 volts between the 5-volt reference circuit terminal 3 and ground.
    4. ⇒If less than the specified range, test the 5-volt reference circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the TBCM.
    ⇒ If greater than the specified range, test the 5-volt reference circuit for a short to voltage. If the circuit tests normal, replace the TBCM.
  4. Verify the scan tool Manual Apply Switch parameter is less than 5 percent.
    5. ⇒If greater than the specified range, test the signal circuit terminal 4 for a short to voltage. If the circuit tests normal, replace the TBCM.
  5. Install a 3A fused jumper wire between the signal circuit terminal 4 and the 5-volt reference circuit terminal 3. Verify the scan tool Manual Apply Switch parameter is greater than 90 percent.
    6. ⇒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 TBCM.
  6. Verify the scan tool Redundant Manual Apply Switch parameter is greater than 90 percent.
    7. ⇒If less than the specified range, test the signal circuit terminal 5 for a short to voltage. If the circuit tests normal, replace the TBCM.
  7. Install a 3A fused jumper wire between the signal circuit terminal 5 and the 5-volt reference circuit terminal 3. Verify the scan tool Redundant Manual Apply Switch parameter is less than 2 percent.
    8. ⇒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 TBCM.
  8. Ignition ON, test for 4.8 - 5.2 volts between the 5-volt reference circuit terminal 6 and ground.
    9. ⇒If less than the specified range, test the 5-volt reference circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the TBCM.
    ⇒ If greater than the specified range, test the 5-volt reference circuit for a short to voltage. If the circuit tests normal, replace the TBCM.
  9. If all circuits test normal, test or replace the trailer brake controller switch panel.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

    •  Trailer Brake Control Switch Replacement
    •  Control Module References for TBCM replacement, setup, and programming