2010 Cadillac CTS Sedan AWD V6-3.6L Page 637

2010 Cadillac CTS Sedan AWD V6-3.6L Page 637

瀚慖f greater than the specified range, test the ground circuit for an open/high resistance.

3. Connect a test lamp between the control circuit terminal A and the ground circuit terminal B.

4. Ignition ON, turn the stop lamps ON and OFF by applying and releasing the brake pedal. The test lamp should turn ON and OFF when

changing between the selected states.

瀚慖f the test lamp is always ON, test the control circuit for a short to voltage. If the circuit tests normal, replace the BCM.

瀚慖f the test lamp is always OFF, test the control circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace

the BCM.

5. If all circuits test normal, replace the CHMSL.

Repair Instructions

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

* High Mount Stop Lamp Replacement (Sedan, V-Series) (See: Lighting and Horns/Center Mounted Brake Lamp/Service and Repair)High

Mount Stop Lamp Replacement (Wagon) (See: Lighting and Horns/Center Mounted Brake Lamp/Service and Repair)

* Control Module References (See: Testing and Inspection/Programming and Relearning) for BCM replacement, setup, and programming

B3920

DTC B3920 or B3921

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 B3920 01

- Group 1 Seat Motors Common Circuit Short to Battery

DTC B3920 02

- Group 1 Seat Motors Common Circuit Short to Ground

DTC B3921 01

- Group 2 Seat Motors Common Circuit Short to Battery

DTC B3921 02

- Group 2 Seat Motors Common Circuit Short to Ground

Diagnostic Fault Information