C1119
DTC C1119
Diagnostic Instructions
* Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure. Initial Inspection and Diagnostic Overview
* Review Strategy Based Diagnosis for an overview of the diagnostic approach.
* Diagnostic Procedure Instructions provides an overview of each diagnostic category.
DTC Descriptor
DTC C1119
- Trailer Brake Control Relay Feedback Circuit
Diagnostic Fault Information
Circuit/System Description
The trailer brake control module diagnostic monitor detects faults on the solid state relay (SSR) driver module feedback circuit.
Conditions for Running the DTC
* DTCs C1114 is not set.
* The ignition is ON.
* Trailer brake is not activated.
Conditions for Setting the DTC
* The TBCM detects an open in the solid state relay control feedback circuit.
* The TBCM detects short to ground in the solid state relay control feedback circuit.
* The TBCM detects short to battery positive in the solid state relay control feedback circuit.
Action Taken When the DTC Sets
* The trailer brake control will be disabled at the end of the current brake apply for the remainder of the ignition cycle.
* The Service Trailer Brake System will be displayed on the Driver Information Center (DIC).
Condition for Clearing the MIL/DTC
* When the condition for the DTC is no longer present.
* The TBCM automatically clears the history DTC when a current DTC is not detected in 40 consecutive drive cycles.
Diagnostic Aids
If there are any DTCs set for GMLAN communication such as U0100, U0121, U0140, or U2099, diagnose them first before to resolve DTCs described in this section.
Diagnose an open circuit in trailer brake control module ground circuit or trailer brake control relay ground circuit will also cause DTC C1119 being set as current DTC. When DTC C1119 is set as current DTC, trailer brake control module ground circuit or trailer brake control relay ground circuit should be diagnose for open circuit, before to diagnosing the trailer brake control relay current feedback circuit.
If there is an aftermarket trailer brake controller, the ITBC must be disconnected. Do not power both ITBC and aftermarket controllers to control the trailer brakes at the same time.
Circuit/System Verification
1. Ignition ON, observe the scan tool brake controls TBCM Relay Feedback Signal volts parameter. The reading should be between 4.8-5.2 volts.
2. Ignition ON, observe the scan tool brake controls Trailer Brake Relay Command volts parameter. The reading should be battery volts.
Circuit/System Testing
Important: All electrical components and accessories must be turned OFF and allowed to power down.
1. Ignition OFF, disconnect the harness connector at the solid state relay module.
2. Test for less than 5 ohms of resistance between the ground circuit terminal B and ground.
* If greater than the specified range, test the ground circuit for an open/high resistance.
3. Ignition ON, test for 4.8-5.2 volts between the 5-volt reference circuit terminal D and ground.
* 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. If all circuits test normal, test or replace the SSR driver module.
Repair Instructions
Perform the Diagnostic Repair Verification after completing the diagnostic procedure. Verification Tests
* Trailer Brake Control Module Replacement
* Refer to to Programming and Relearning for programming and setup procedures. Programming and Relearning