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 B250D 00: Left Rear Door Unlatch Low Control Circuit

DTC B250E 00: Right Rear Door Unlatch Low Control Circuit

Diagnostic Fault Information

Circuit

Short to Ground

Open/High Resistance

Short to Voltage

Signal Performance

Rear Access Panel Relay B+

2

2

--

--

Right Access Panel Release Signal

1, 2

1

1

--

Left Access Panel Release Signal

1, 2

1

1

--

Underhood Interlock Relay Control

B312A 02

B312A 05

B312A 05

--

LH Access Panel Relay Control

B250D 00

B250D 00

B250D 00

--

RH Access Panel Relay Control

B250E 00

B250E 00

B250E 00

--

Access Panel Latch Interlock Control

2

2

--

--

RH Access Panel Latch Control

2

2

2

--

LH Access Panel Latch Control

2

2

2

--

Rear Access Panel Switch Ground

--

1

1

--

Underhood Interlock Relay Ground

--

2

2

--

1. Rear Access Panel Switch Inoperative.

2. Rear Access Panel Latch Inoperative.

Circuit/System Description

The body control module (BCM) monitors the signal from the rear access panel release switches. When the BCM detects a request for the rear panel to open, it will provide a ground for the appropriate rear access panel relay. This will energize the relay and cause it to supply voltage to the appropriate rear access panel latch.

Conditions for Running the DTC

The system voltage is 9-16 volts.

Conditions for Setting the DTC

B250D 00

When the BCM detects a fault in the left access release panel relay control circuit.

B250E 00

When the BCM detects a fault in the right access release panel relay control circuit.

Action Taken When the DTC Sets

Rear access panels 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

Release Systems Schematics

Connector End View Reference

Component Connector End Views

Description and Operation

Access Panel 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

Observe the operation of the left and right rear access panel while pressing the left and right access panel switch. The appropriate latch should release the rear access panel.

Circuit/System Testing

  1. Ignition OFF, disconnect the appropriate REAR ACCESS PANEL relay.
  2. Ignition ON, verify that a test lamp illuminates between the relay coil B+ circuit terminal 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 relay coil control circuit terminal and the relay coil B+ circuit terminal.
  5. Command the access panel latch by pressing and releasing the appropriate access panel switch. The test lamp should turn ON and OFF 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 all circuits test normal, test or replace the REAR ACCESS PANEL relay.

Component Testing

  1. Ignition OFF, disconnect the appropriate REAR ACCESS PANEL 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. Install a 25-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.
  7. 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