B2623

DTC B2622 or B2623

Circuit Description

The body control module (BCM) receives a variable voltage signal from the instrument panel (I/P) dimmer switch requesting to illuminate the I/P controls illumination lamps to a desired intensity. When this occurs, the BCM directly sends a variable voltage based on the I/P dimmer switch position through the I/P lamps supply voltage circuit to the I/P controls illumination lamps.

DTC Descriptors

This diagnostic procedure supports the following DTCs:

* DTC B2622 Dimming Display Pulse Width Modulation (PWM) Input Circuit Low
* DTC B2623 Dimming Display Pulse Width Modulation (PWM) Input Circuit High

Conditions for Running the DTC

The battery voltage must be between 9-16 volts.

Conditions for Setting the DTC

* When the BCM receives an I/P controls illumination lamp request signal and the I/P lamps supply voltage circuit is shorted to ground
* When the BCM is not receiving an I/P controls illumination lamp request signal and the I/P lamps supply voltage circuit is shorted to voltage

Action Taken When the DTC Sets

The I/P controls illumination lamps will not operate or are always ON.

Conditions for Clearing the MIL/DTC

* This DTC will clear on current status after the condition for setting the fault is corrected.
* A history DTC will clear after 100 consecutive ignition cycles without a fault present.
* History and current DTCs can be cleared using a scan tool.

Diagnostic Aids

Perform a visual inspection for loose or poor connections at all related components. Refer to Testing for Intermittent Conditions and Poor Connections. Component Tests and General Diagnostics

Test Description

Step 1 - Step 6:

The numbers below refer to the step numbers on the diagnostic table.
2. This step determines by process of elimination which, if any, dimmable component is causing the DTC to set.
3. This step determines if the problem exists in the wiring or the BCM.
5. After replacement of the BCM, you must calibrate the new module for proper operation.