• | 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. |
Circuit | Short to Ground | Open/High Resistance | Short to Voltage | Signal Performance |
---|---|---|---|---|
B+ | C1112 00 | C1112 00 | -- | -- |
Relay Feedback Signal | C1119 00 | C1119 00 | C1119 00 | -- |
Solid State Relay Enable Control | C1112 00 | C1112 00 | C1113 01 | -- |
Trailer Brake Output Supply Voltage Control | C1114 00 | C1114 00 | C1113 01,C1114 00 | -- |
Intergrated Trailer Brake Relay Control Active Low Control | C1112 00 | C1112 00 | C1112 00 | -- |
Ground | -- | C1112 | -- | -- |
The trailer brake control relay recieves inputs from the trailer brake control module(TBCM), these inputs are used to determine the amount of voltage the relay will supply to the trailer brakes
• | Ignition ON. |
• | Battery voltage is 9.5 - 17 volts. |
• | The module is powered up and completes initialization. |
The TBCM circuit reference voltage for the trailer brake control relay is below 4.8 volts or above 5.2 volts.
• | The TBCM detects a short to ground, open or a short to voltage on the integrated trailer brake relay control active low circuit. |
• | The TBCM detects an open in the battery positive voltage circuit to the trailer brake control relay. |
• | The TBCM detects an open in the ground circuit to the trailer brake control relay. |
• | The TBCM detects a short to ground or open in the solid state relay enable circuit. |
• | The TBCM detects a short to voltage in the solid state relay enable circuit. |
• | The TBCM detects a short to voltage in the trailer brake output supply voltage control circuit. |
The TBCM detects a short to ground, open or a short to voltage on the solid state relay enable circuit.
The TBCM detects a short to ground, open or a short to voltage on the relay feedback circuit.
• | 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. |
• | 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. |
Trailer Brake Control Schematics
Trailer Brake Controls Description and Operation
Control Module References for scan tool information
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.
⇒ | If greater than the specified range, test the ground circuit for an open/high resistance. |
⇒ | If the test lamp does not illuminate, test the B+ circuit for a short to ground or an open/high resistance. If the circuit tests normal and the STUD 2 fuse is open, replace the trailer brake control relay. |
⇒ | If less than the specified range, test the control 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 control circuit for a short to voltage. If the circuit tests normal, replace the TBCM. |
⇒ | If less than the specified range, test the control 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 control circuit for a short to voltage. If the circuit tests normal, replace the TBCM. |
⇒ | If less than the specified range, test the control 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 control circuit for a short to voltage. If the circuit tests normal, replace the TBCM. |
⇒ | If greater than the specified range, test the control circuit for a short to voltage. If the circuit tests normal, replace the TBCM. |
⇒ | If less than the specified range, test the control circuit for a short to ground. If the circuit tests normal, replace the TBCM. |
⇒ | If greater than the specified range, test the control circuit for a or an open/high resistance. If the circuit tests normal, replace the TBCM. |
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
• | Control Module References for TBCM replacement, setup, and programming |