GM Service Manual Online
For 1990-2009 cars only

Diagnostic Instructions

    • Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure.
    • Review Strategy Based Diagnosis for an overview of the diagnostic approach.
    •  Diagnostic Procedure Instructions provides an overview of each diagnostic category.

DTC Descriptors

DTC B320A 39: Front Door Window Motor Internal Electronic Failure

DTC B320A 42: Front Door Window Motor Calibration Data Set Not Programmed

DTC B320A 4B: Front Door Window Motor Calibration Not Learned

Diagnostic Fault Information

Circuit

Short to Ground

Open/High Resistance

Short to Voltage

Signal Performance

Driver Window Motor B+

U1511 00, B320A 4B

U1511 00, B320A 4B

--

--

LR Window Switch B+

3

3

--

--

Passenger Window Motor B+

U1511 00, B320A 4B

U1511 00, B320A 4B

--

--

RR Window Switch B+

4

4

--

--

Driver Window Motor Serial Data

U1500 02, B320A 4B

U1511 00, B320A 4B

U1511 00, B320A 4B

--

Passenger Window Motor Serial Data

U1500 02, U1511 00, B320A 4B

U1511 00, B320A 4B

U1511 00, B320A 4B

--

LR Window Motor Control

3

3

3

--

RR Window Motor Control

4

4

4

--

Window Master Switch LR Down Control

B3820 00

B3820 00

B3820 00

--

LR Window Master Switch Lockout Control

B3821 00

B3821 00

B3821 00

--

RR Window Master Switch Lockout Control

B3824 00

B3824 00

B3824 00

--

Window Master Switch LR Up Control

B3819 00

B3819 00

B3819 00

--

Window Master Switch RR Down Control

B3823 00

B3823 00

B3823 00

--

Window Master Switch RR Up Control

B3822 00

B3822 00

B3822 00

--

LR Window Switch Ground

--

3

3

--

Driver Window Motor Ground

--

U1511 00, B320A 4B

1

--

Passenger Window Motor Ground

--

U1511 00, B320A 42, B320A 4B

2

--

RR Window Switch Ground

--

4

4

--

1. Driver Window Malfunction

2. Passenger Window Malfunction

3. Left Rear Window Malfunction

4. Right Rear Window Malfunction

Circuit/System Description

The front door power window motors communicate with the driver door module (DDM) and passenger door module (PDM) via serial data. The motors contain a logic module which must be normalized or programmed any time the window motor is serviced to provide proper operation and communication between door modules and window motors.

Conditions for Running the DTC

Power window switch activated.

Conditions for Setting the DTC

B320A 39

An internal malfunction or a momentary voltage spike has been detected by the DDM or PDM in the front power window motor while commanding the window UP/DOWN.

B320A 42

A not normalized/programmed driver or front passenger door power window motor.

B320A 4B

The front window motor experiences a loss of voltage in the B+ circuit or an open/high resistance in the serial data circuit.

Action Taken When the DTC Sets

The affected power window will malfunction.

Conditions for Clearing the DTC

B320A 39

If the DTC is current, the appropriate window motor must be replaced before the DTC can be cleared.

B320A 42

The affected power window motor must be programmed before the DTC can be cleared.

B320A 4B

The affected power window motor must be calibrated before the DTC can be cleared.

Reference Information

Schematic Reference

Moveable Window Schematics

Connector End View Reference

Component Connector End Views

Description and Operation

Power Windows Description and Operation

Electrical Information Reference

    •  Circuit Testing
    •  Connector Repairs
    •  Testing for Intermittent Conditions and Poor Connections
    •  Wiring Repairs

Scan Tool Reference

Control Module References for scan tool information

Circuit/System Verification

B320A 39

Ignition ON, command the appropriate power window DOWN and UP with a scan tool. The power window should go DOWN and UP as commanded.

If the DTC is current and the power window is inoperative, replace the power window motor.
If the DTC is history and the power window performs the UP and DOWN functions, clear the DTC.

B320A 42

Ignition ON, reprogram the appropriate power window and operate the power window within the conditions for running the DTC, verify the DTC does not reset.

If the DTC resets, replace the power window motor.

B320A 4B

Command the front window motor fully DOWN by pressing and holding the front window switch for 5 seconds, then command the front window motor fully UP by lifting and holding the front window switch for 5 seconds.

If the DTC resets, replace the power window motor.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

Front Side Door Window Regulator Motor Replacement