2010 Cadillac Truck SRX FWD V6-3.0L Page 730

2010 Cadillac Truck SRX FWD V6-3.0L Page 730

Circuit/System Testing

1. Ignition OFF, disconnect the X1 harness connector at the K68 trailer lighting control module.

2. Test for infinite resistance between the control circuit terminal 8 and ground.

瀚慖f less than the specified value, test the control circuit for a short to ground. If the circuit tests normal, replace the X88 trailer connector.

3. Test for less than 1 ohm between the control circuit terminal 8 at the K68 trailer lighting control module and control circuit terminal 2 at the

X88 trailer connector.

瀚慖f greater than the specified range, test the control circuit for a short to voltage or an open/high resistance. If the circuit tests normal,

replace the X88 trailer connector.

4. If all the circuits test normal, replace the K68 trailer lighting control module.

Repair Instructions

Perform the Diagnostic Repair Verification (See: Verification Tests) after completing the diagnostic procedure.

Control Module References (See: Testing and Inspection/Programming and Relearning) for the trailer brake control module replacement,

programming and setup

B3890

DTC B3890

Diagnostic Instructions

* Perform the Diagnostic System Check - Vehicle (See: Testing and Inspection/Initial Inspection and Diagnostic Overview/Diagnostic System

Check - Vehicle) prior to using this diagnostic procedure.

* Review Strategy Based Diagnosis (See: Testing and Inspection/Initial Inspection and Diagnostic Overview/Strategy Based Diagnosis) for an

overview of the diagnostic approach.

* Diagnostic Procedure Instructions (See: Testing and Inspection/Initial Inspection and Diagnostic Overview/Diagnostic Procedure

Instructions) provides an overview of each diagnostic category.

DTC Descriptors

DTC B3890 02

- Trailer Backup Lamps Circuit Short to Ground

DTC B3890 04

- Trailer Backup Lamps Circuit Open

Diagnostic Fault Information

Circuit/System Description

The trailer brake control module will receive a serial data message from the BCM indicating that the vehicle backup lamps have been activated. The

trailer brake control module will then apply system voltage to the trailer backup lamps through their respective voltage supply circuits.

Conditions for Running the DTC

When the trailer backup lamps are turned on.

Conditions for Setting the DTC

B3890 02

The trailer brake control module detects a short to ground on the trailer backup lamp control circuit.

B3890 04

The trailer brake control module detects an open/ high resistance on the trailer backup lamp control circuit.