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 B3130 00: All Door Unlock Circuit

Diagnostic Fault Information

Circuit

Short to Ground

Open/High Resistance

Short to Voltage

Signal Performance

DDM B+

U0199 00

U0199 00

--

--

Door Lock Relay Switch B+

4

4

--

--

Door Unlock Relay Coil B+

3

3

--

--

Door Unlock Relay Switch B+

3

3

--

--

Door Unlatch (Limo) Relay Switch B+

5

5

--

--

Right Middle Door Park Relay Switch B+

5

5

--

--

Left Middle Door Park Relay Switch B+

5

5

--

--

FPDM B+

U0200 00

U0200 00

--

--

Driver Door Lock Actuator Lock Control

B3225 00

B3225 00

B3225 00

--

Driver Door Lock Actuator Unlock Control

B3225 00

B3225 00

B3225 00

--

Driver Door Key Switch Low Reference

--

1,2,3,4

1,2,3,4

--

Driver Door Key Switch Signal

1,2,3,4

1,2,3,4

1,2,3,4

--

Park Enable Signal

B0005 00

5

5

--

Passenger Door Lock Actuator Lock Control

B3135 00

B3135 00

B3135 00

--

Passenger Door Lock Actuator Unlock Control

B3130 00

B3130 00

B3130 00

--

Rear Door Latch Actuator Lock Control

4

4

4

--

Rear Door Latch Actuator Unlock Control

3

3

3

--

Middle Door Latch Actuator Lock Control

4

4

4

--

Middle Door Latch Actuator Unlock Control

3

3

3

--

Back Door Latch Actuator Lock Control

4

4

4

--

Back Door Latch Actuator Unlock Control

3

3

3

--

Right Middle Door Release Switch Control

5

5

5

--

Left Middle Door Release Switch Control

5

5

5

--

DDM Ground

--

U0199 00

U0199 00

--

Door Unlock Relay Switch Ground

--

3

3

--

Door Lock Relay Coil Ground

---

4

4

--

Door Lock Relay Switch Ground

--

4

4

--

Door Unlatch (Limo) Relay Coil Ground

--

5

5

--

Left Middle Door Park Relay Ground

--

5

5

--

Right Middle Door Park Relay Ground

--

5

5

--

FPDM Ground

--

U0200 00

U0200 00

--

1. Driver Door Latch Malfunction

2. Passenger Door Latch Malfunction

3. Rear, Middle, Back Door Unlock Inoperative

4. Rear, Middle, Back Door Lock Inoperative

5. Release Switch Malfunction

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. With the lock relay coil energized, the switch contacts close allowing battery voltage to flow from the REAR DOOR LCK fuse through the relay switch contacts to the left and right door lock/unlock motors. A ground path is provided by the unlock relay controlled output circuit through the unlock relay switch contacts to ground. The process to unlock the rear doors reverses the flow of current. The BCM applies ground to the rear door lock actuator unlock control circuit which energizes the unlock relay coil. With the unlock relay coil energized, the switch contacts close allowing battery voltage to flow from the REAR DOOR LCK fuse through the relay switch contacts to the left and right door lock/unlock motors. Ground is provided through the lock relay controlled output circuit through the lock relay switch contacts to ground.

Conditions for Running the DTC

Battery voltage must be between 9-16 volts.

Conditions for Setting the DTC

When the BCM detects a fault in the rear door unlock relay control circuit.

Actions Taken When the DTC Sets

The BCM will disable all unlock 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 Locks 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 rear doors to LOCK and UNLOCK with a scan tool. The rear doors should LOCK and UNLOCK.

Circuit/System Testing

  1. Ignition OFF, disconnect the DR UNLCK relay.
  2. Ignition ON, verify that a test lamp illuminates between the B+ circuit terminal 8 and ground.
  3. If the test lamp does not illuminate, test the B+ circuit for a short to ground or an open/high resistance.
  4. Connect a test lamp between the B+ circuit terminal 8 and the control circuit terminal 9.
  5. Ignition ON, command the rear door locks to LOCK and UNLOCK with a scan tool. The test lamp should briefly illuminate when changing between the commanded states.
  6. 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.
  7. If the circuits test normal, test or replace the DR UNLCK relay.

Component Testing

  1. Ignition OFF, disconnect the DR UNLCK relay.
  2. Test for 60-200 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 range, replace the relay.
  8. Install a 3-amp 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 range, 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