B2652
DTC B2652
Diagnostic Instructions
* Perform the Diagnostic System Check - Vehicle (Diagnostic System Check - Vehicle) prior to using this diagnostic procedure.
* Review Strategy Based Diagnosis (Strategy Based Diagnosis) for an overview of the diagnostic approach.
* Diagnostic Procedure Instructions (Diagnostic Procedure Instructions)provides an overview of each diagnostic category.
DTC Descriptor
DTC B2652 00
- Passenger Compartment Dimming 3 Circuit
Diagnostic Fault Information
Circuit/System Description
The body control module (BCM) supplies a voltage reference through the instrument panel (I/P) dimming voltage reference circuit to the interior lamp dimmer switch, which is part of the headlamp switch. When the dimmer switch is placed in a desired position, reference voltage is applied through the dimmer switch rheostat and the I/P lamps dimmer switch signal circuit to the BCM. The BCM interprets this voltage signal, then applies a pulse width modulated (PWM) voltage through the instrument panel lamp control circuits illuminating the instrument panel components.
Conditions for Running the DTC
* The ignition is ON.
* The headlamps or park lamps ON.
Conditions for Setting the DTC
The BCM detects a short to ground on the instrument panel lamps control circuit.
Action Taken When the DTC Sets
The BCM does not attempt to illuminate the instrument panel lamps.
Conditions for Clearing the DTC
A history DTC will clear once 100 consecutive malfunction-free ignition cycles have occurred.
Reference Information
Schematic Reference
Interior Lights Dimming Schematics (Interior Lights Dimming Schematics)
Connector End View Reference
Component Connector End Views (Connector End Views By Name)
Description and Operation
Interior Lighting Systems Description and Operation (Interior Lighting Systems)
Electrical Information Reference
* Circuit Testing (Circuit Testing)
* Connector Repairs (Connector Repairs)
* Testing for Intermittent Conditions and Poor Connections (Testing For Intermittent Conditions and Poor Connections)
* Wiring Repairs (Wiring Repairs)
Scan Tool Reference
Control Module References (Programming and Relearning)for scan tool information
Circuit/System Verification
Observe the scan tool Dimming Control Signal parameter. The parameter should change as the dimming is increased and decreased.
Circuit/System Testing
Note: Each dimming lighting component may need to be disconnected to isolate a short to voltage or short to ground. Use the schematic to identify the following:
* Dimming lighting components the vehicle is equipped with.
* Component locations on the dimming control circuit
* Each component's control and ground circuit terminals
1. Ignition OFF, disconnect the harness connector at any component with inoperative dimming lighting.
2. Ignition OFF, scan tool disconnected, interior lamps OFF, doors CLOSED, test for less than 5 ohm between the ground circuit and ground.
• If greater than the specified value, test the ground circuit for an open/high resistance.
3. Connect a test lamp between the control circuit terminal and ground.
4. Command the Courtesy Lamps ON and OFF with a scan tool. The test lamp should turn ON and OFF when changing between the commanded states.
• If 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.
• If the test lamp is always ON, test the control circuit for a short to voltage. If the circuit tests normal, replace the BCM.
5. If all circuits test normal, test or replace the component with the inoperative dimming lighting.
Repair Instructions
Perform the Diagnostic Repair Verification (Verification Tests) after completing the diagnostic procedure.
* Refer to the appropriate replacement procedure for the lighting component that requires replacement.
* Control Module References (Programming and Relearning)for BCM replacement, programming and setup