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 Descriptor

DTC B3225 00: Lock Motor Circuit

Diagnostic Fault Information

Circuit

Short to Ground

Open/High Resistance

Short to Voltage

Signal Performance

Driver Door Module B+

U0199 00

U0199 00

--

--

Front Passenger Door Module B+

U0200 00

U0200 00

--

--

Driver Door Latch Control

B3225 00

1

1

--

Passenger Door Latch Control

B3225 00

2

2

--

Door Lock Relay Control

B3135 00

B3135 00

B3135 00

--

Door Unlock Relay Control

B3130 00

B3130 00

B3130 00

--

Rear Door Latch Control

3,4

3,4

3,4

--

Door Lock/Unlock Relay Ground

--

3,4

3,4

--

Driver Door Module Ground

--

U0199 00

1

--

Front Passenger Door Module Ground

--

U0200 00

2

--

1. Driver Door Latch Malfunction

2. Passenger Door Latch Malfunction

3. Rear Door Unlock Inoperative

4. Rear Door Lock Inoperative

Circuit/System Description

The driver and front passenger power door lock switches are integral components of the driver door module (DDM) and passenger door module (PDM). The switches consist of 2 positions, lock and unlock, and are in the normally open state. When placed in either the lock or unlock positions, the switches provide a direct input to there respective door control module. When a power door lock switch is operated to the lock or unlock position, the associated door control module responds by sending a serial data message indicating a change in the switch's position. This serial data message is received by the opposite door control module as well as the body control module (BCM). The DDM and PDM respond to the lock/unlock request by activating there associated power door lock motors to the appropriate direction to lock or unlock the front doors. The BCM is responsible for controlling the left and right rear passenger door lock motors. The BCM, upon receipt of a lock or unlock serial data signal, will control either the rear door lock or unlock relay. When the appropriate door lock relay is energized, the rear power door lock motors will lock or unlock the rear doors.

Conditions for Running the DTC

Battery voltage must be between 9-16 volts.

Conditions for Setting the DTC

When the DDM or PDM detects a short to ground in their respective actuator lock control circuits.

Actions Taken When the DTC Sets

The DDM/PDM will disable all front lock requests.

Conditions for Clearing the DTC

    • The DTC will be current for as long as the fault is present.
    • When the fault is no longer present, the DTC will be a history DTC.
    • A history DTC will clear after 50 ignition cycles.

Reference Information

Schematic Reference

Door Lock/Indicator Schematics

Connector End View Reference

Component Connector End Views

Description and Operation

Power Door Latch 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

Ignition ON, command the front doors to LOCK and UNLOCK by using the driver and passenger door lock switches. The front doors should perform the LOCK and UNLOCK functions from each switch.

Circuit/System Testing

Front Door Lock Malfunction

  1. Ignition OFF, disconnect the harness connector at the appropriate front door latch.
  2. Ignition ON, test for less than 5 ohms between the control circuit terminal listed below and ground:
  3. • Driver door latch control circuit terminal 2
    • Driver door latch control circuit terminal 3
    • Front passenger door latch control circuit terminal 5
    • Front passenger door latch control circuit terminal 6
    If greater than the specified range, test the control circuit for a short to voltage or an open/hign resistance. If the circuit tests normal, replace the door module.
  4. Connect a test lamp between control circuit terminals of the front door latch listed below:
  5. • Driver door latch control circuit terminal 2 and control circuit terminal 3
    • Front passenger door latch control circuit terminal 5 and control circuit terminal 6
  6. Command the door latch to LOCK and UNLOCK by using the door lock switch. The test lamp should briefly illuminate when commanding the LOCK and UNLOCK states.
  7. If the test lamp is always OFF during either of the commands, test either control circuit for a short to ground. If the circuits test normal, replace the door module.
  8. If all circuits test normal, test or replace the front door latch.

Component Testing

Door Latch Test

  1. Ignition OFF, disconnect the harness connector at the appropriate door latch.
  2. Ignition ON, install a 15 amp fused jumper wire between the control terminal listed below and 12 volts:
  3. • Driver door latch control terminal 3
    • Passenger door latch control terminal 5
  4. Momentarily install a jumper wire between the control terminal listed below and ground. The door latch should perform the LOCK/ UNLOCK function:
  5. • Driver door latch control terminal 4
    • Passenger door latch control terminal 6
    If the function does not perform as specified, replace the door latch.
  6. Reverse the jumper wires; the door latch should perform the UNLOCK/LOCK function.
  7. If the function does not perform as specified, replace the door latch.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

    •  Front Side Door Latch Replacement
    •  Control Module References for DDM and PDM replacement, setup, and programming