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 from the CHMSL/BCK-UP fuse through the instrument panel lamp control circuit and the interior backlighting components dim to the requested level.
Conditions for Running the DTC
* Battery voltage must be between 9-16 volts.
* Park lamps ON.
Conditions for Setting the DTC
DTC B2652 00 will set for the following conditions:
* The BCM detects a short to ground in the instrument panel lamps control circuit.
* The BCM detects a short to ground or an open/high resistance in the BCM B+ circuit terminal 2 X2 or the BCM B+ circuit terminal 4 X4.
Action Taken When the DTC Sets
The BCM will not DIM or illuminate any I/P lamps supplied by the I/P lamps dimmer switch.
Conditions for Clearing the DTC
* The condition responsible for setting the DTC no longer exists.
* 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 Testing
1. Ignition OFF, disconnect the X2 harness connector at the BCM.
2. Ignition ON, verify that a test lamp illuminates between the B+ circuit terminal 2 and ground.
• If the test lamp does not illuminate, test the B+ circuit for a short to ground or an open/high resistance.
3. Ignition OFF, connect the X2 harness connector at the BCM.
4. Disconnect the X4 harness connector at the BCM.
5. Ignition ON, verify that a test lamp illuminates between the B+ circuit terminal 4 and ground.
• If the test lamp does not illuminate, test the B+ circuit for a short to ground or an open/high resistance.
6. Ignition OFF, connect the X4 harness connector at the BCM.
7. Disconnect the harness connectors at the following components.
* Headlamp Switch
* Instrument Panel Cluster (IPC)
* Driver Window Switch
* Driver Door Lock Switch
* Outside Rearview Mirror Switch
* Passenger Window Switch
* Passenger Door Lock Switch
8. Ignition ON, clear the DTC with a scan tool.
9. Operate the system within the Conditions for Running the DTC and verify the DTC does not reset.
• If the DTC resets, test the control circuits for a short to ground. If the circuits test normal, replace the BCM.
10. Reconnect each component one at a time and verify that the DTC does not reset as current.
• If the DTC resets as current, test or replace the component responsible for setting the DTC.
11. If all circuits test normal, replace the BCM.
Repair Instructions
Perform the Diagnostic Repair Verification (Verification Tests) after completing the diagnostic procedure.
* Headlamp Switch Replacement (Impala) (Service and Repair)
* Instrument Cluster Replacement (Service and Repair)
* Front Side Door Window Switch Replacement (Impala) (Front Side Door Window Switch Replacement)
* Door Lock Switch Replacement (Impala) (Service and Repair)
* Power Mirror Switch Replacement (Service and Repair)
* Control Module References (Programming and Relearning) for BCM replacement, setup, and programming