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 B3130 00: All Door Unlock Circuit

DTC B3135 00: All Door Lock 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

1

1

1

--

Passenger Door Latch Control

2

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 rear passenger door locks are controlled by the body control module (BCM). When a door lock switch is operated to the lock position, the BCM applies voltage to the rear door lock actuator lock control circuit which energizes the lock relay. The BCM applies ground to the rear door lock actuator unlock control circuit which energizes the unlock relay coil.

Conditions for Running the DTC

Battery voltage is between 9-16 volts.

Conditions for Setting the DTC

B3130 00

The BCM detects a short to voltage in the UNLOCK relay control circuit.

B3135 00

The BCM detects a short to ground in the LCK relay control circuit.

Actions Taken When the DTC Sets

The rear door locks will malfunction.

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 Lock Rear Doors and Unlock Rear Doors with a scan tool. The rear doors should perform the LOCK and UNLOCK functions.

If B3130 00 is current, refer to Door Lock Malfunction
If B3135 00 is current, refer to Door Unlock Malfunction

Circuit/System Testing

Door Lock Malfunction

  1. Ignition OFF, disconnect the UNLOCK relay.
  2. Connect a test lamp between the B+ circuit terminal 86 and the control circuit terminal 85.
  3. Command the Lock Rear Doors and Unlock Rear Doors with a scan tool. The test lamp should turn ON and OFF when changing between the commanded states.
  4. If the test lamp is always ON, test the control circuit for a short to ground. If the circuit tests normal, replace the BCM.
    If the test lamp is always OFF, test the control circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the BCM.
  5. If the circuits test normal, test or replace the UNLCK relay.

Door Unlock Malfunction

  1. Ignition OFF, disconnect the LCK relay.
  2. Connect a test lamp between the control circuit terminal 85 and ground.
  3. Command the Lock Rear Doors and Unlock Rear Doors with a scan tool. The test lamp should turn ON and OFF when changing between the commanded states.
  4. If the test lamp is always ON, test the control circuit for a short to voltage. If the circuit tests normal, replace the BCM.
    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.
  5. If the circuits test normal, test or replace the LCK relay.

Component Testing

Relay Test

  1. Ignition OFF, disconnect the appropriate relay.
  2. Test for 60-180 ohms between terminals 85 and 86.
  3. If not within the specified range, replace the relay.
  4. Test for infinite resistance between the following terminals:
  5. • 30 and 86
    • 30 and 87
    • 30 and 85
    • 85 and 87
    If not the specified value, replace the relay.
  6. Test for less than 2 ohms between terminals 30 and 87A.
  7. If greater than the specified value, replace the relay.
  8. Install a 25A fused jumper wire between relay terminal 85 and 12 volts. Install a jumper wire between relay terminal 86 and ground. Test for less than 2 ohms between terminals 30 and 87.
  9. If greater than the specified value, replace the relay.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

    •  Relay Replacement
    •  Control Module References for BCM replacement, setup, and programming