Chevrolet Silverado / GMC Sierra. Manual — part 2800

Scan Tool Reference

Control Module References for Scan Tool Information

Circuit/System Verification

1. 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.

2. 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

module.

2. Test for less than 5 ohms of resistance between the ground circuit terminal 8 and ground.

If greater than the specified range, test the ground 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 6 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 trailer brake controller switch module.

Repair Procedures

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

Control Module References for TBCM replacement, setup, and programming

Trailer Brake Control Module Replacement

DTC C1119

Diagnostic Instructions

IMPORTANT: All electrical components and accessories must be turned OFF

and allowed to power down.

2008 Chevrolet Silverado 1500

2008 BRAKES Trailer Brake Controls - Cab & Chassis Sierra, Cab & Chassis Silverado, Sierra & Silverado

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 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

Circuit

Short to

Ground

High

Resistance

Open

Short to

Voltage

Signal

Performance

Relay Control Active Low
Circuit

C1119

-

C1119

-

-

TBCM Ground Circuit

-

-

C1119

-

-

2008 Chevrolet Silverado 1500

2008 BRAKES Trailer Brake Controls - Cab & Chassis Sierra, Cab & Chassis Silverado, Sierra & Silverado

(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 TBCM must
be disconnected. Do not power both TBCM and aftermarket controllers to control the trailer
brakes at the same time.

Reference Information

Schematic Reference

Trailer Brake Control Schematics

Description and Operation

Trailer Brake Controls Description and Operation

Connector End View Reference

Component Connector End Views

Electrical Information Reference

Circuit Testing

Connector Repairs

Testing for Intermittent Conditions and Poor Connections

Wiring Repairs

2008 Chevrolet Silverado 1500

2008 BRAKES Trailer Brake Controls - Cab & Chassis Sierra, Cab & Chassis Silverado, Sierra & Silverado