B251B
DTC B251A-B251F
Diagnostic Instructions
* Perform the Diagnostic System Check - Vehicle (Diagnostic System Check - Vehicle) prior to using this diagnostic procedure.
* Review Strategy Based Diagnosis (Strategy Based Diagnosis) for an overview of the diagnostic approach.
* Diagnostic Procedure Instructions (Diagnostic Procedure Instructions) provides an overview of each diagnostic category.
DTC Descriptors
DTC B251A 01
- All Door Unlatch Circuit Short to Battery
DTC B251A 02
- All Door Unlatch Circuit Short to Ground
DTC B251B 02
- Driver Door Unlatch High Control Circuit Short to Ground
DTC B251B 04
- Driver Door Unlatch High Control Circuit Open
DTC B251C 04
- Passenger Door Unlatch High Control Circuit Open
DTC B251D 04
- Left Rear Door Unlatch High Control Circuit Open
DTC B251E 04
- Right Rear Door Unlatch High Control Circuit Open
Diagnostic Fault Information
Circuit/System Description
The system is designed so that when the operator approaches a locked vehicle with the keyless entry transmitter, the keyless entry control module will detect the keyless entry transmitter and when an exterior door handle is pulled the keyless entry control module will command all doors to unlock and the door to unlatch allowing the door to be pulled open.
Conditions for Running the DTC
The system voltage is 9-16 V.
Conditions for Setting the DTC
B251A 01
The keyless entry control module detects a short to voltage on the passenger or left rear or right rear door latch motor unlatch low control circuit.
B251A 02
The keyless entry control module detects a short to ground on the passenger or left rear or right rear door latch motor unlatch low control circuit.
B251A 02
The BCM detects a short to ground on the passenger door lock actuator unlock control circuit.
B251B 04
The keyless entry control module detects an open/high resistance in the driver door latch motor unlatch control circuit.
B251B 02
The BCM detects a short to ground on the driver door lock actuator unlock control circuit
B251C 04
The keyless entry control module detects an open/high resistance on the passenger door latch motor unlatch control circuit.
B251D 04
The keyless entry control module detects an open/high resistance on the left rear door latch motor unlatch control circuit.
B251E 04
The keyless entry control module detects an open/high resistance on the right rear door latch motor unlatch control circuit.
Action Taken When the DTC Sets
The affected door will require a pull of the exterior door handle to unlock the door and a second pull of the exterior door handle to open the door.
Conditions for Clearing the DTC
* This 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 40 ignition cycles
Diagnostic Aids
DTC B1330 03 and B251A 02 may sent concurrently, correct the condition for setting DTC B1330 03 first before performing diagnostics testing for B251A 02. Refer to Diagnostic Trouble Code (DTC) List - Vehicle (Diagnostic Trouble Code (DTC) List - Vehicle) to locate the correct procedure.
Reference Information
Schematic Reference
Door Lock/Indicator Schematics (Door Lock/Indicator Schematics)
Connector End View Reference
Component Connector End Views (Connector End Views By Name)
Description and Operation
Power Door Locks Description and Operation (Description and Operation)
Electrical Information Reference
* Circuit Testing (Circuit Testing)
* Connector Repairs (Connector Repairs)
* Testing for Intermittent Conditions and Poor Connections (Testing for Intermittent Conditions and Poor Connections)
* Wiring Repairs (Wiring Repairs)
Scan Tool Reference
Control Module References (Programming and Relearning) for scan tool information
Circuit/System Verification
1. Ignition OFF, with the doors closed and locked, approach the vehicle with the keyless entry transmitter and pull the exterior driver door handle. The driver door should unlock and unlatch allowing the driver door to be pulled open.
• If the driver door will not unlock and open with a single pull of the exterior door handle, refer to Driver Door Latch Malfunction.
2. With the doors closed and locked, approach the vehicle with the keyless entry transmitter and pull the exterior passenger door handle or the exterior left rear door handle or the exterior right rear door handle. The appropriate door should unlock and unlatch allowing the door to be pulled open.
• If all the passenger, left rear and right rear doors will not unlock and open with a single pull of the exterior door handle, refer to Passenger and Rear Door Release Command Inoperative.
• If a door will not unlock and open with a single pull of the door handle, refer to Passenger or Rear Door Latch Malfunction.
Circuit/System Testing
Driver Door Latch Malfunction
1. Ignition OFF, disconnect the X2 harness connector at the K84 keyless entry control module.
2. Test for less than 10 ohm between the ground circuit terminal 6 and ground.
• If greater than the specified range, test the ground circuit for an open/high resistance.
3. Ignition OFF, connect the X2 harness connector and disconnect the X4 harness connector at the K84 keyless entry control module.
4. Test for infinite resistance between the control circuit terminal 3 and ground.
• If less than the specified value, test the control circuit for a short to ground. If the circuit tests normal, replace the K9 BCM.
5. Ignition OFF, connect the X4 harness connector at the K84 keyless entry control module.
6. Disconnect the harness connector at the A23D door latch assembly - driver.
7. Connect a test lamp between the control circuit terminal 5 and control circuit terminal 10.
8. Pull and release the exterior driver door handle, the test lamp should briefly illuminate while the exterior door handle is being pulled.
• If the test lamp is always OFF, test either control circuit for a short to ground or an open/high resistance. If the circuits test normal, replace the K84 keyless entry control module.
• If the test lamp is always ON, test either control circuit for a short to voltage. If the circuits test normal, replace the K84 keyless entry control module.
9. If all circuits test normal, test or replace the A23D door latch assembly - driver.
Passenger and Rear Door Release Command Inoperative
1. Ignition OFF, disconnect the X4 harness connector at the K84 keyless entry control module.
2. Test for infinite resistance between the control circuit terminal 14 and ground.
• If less than the specified value, test the control circuit for a short to ground. If the circuit tests normal, replace the K9 BCM.
3. If all circuits test normal, replace the K84 keyless entry control module.
Passenger or Rear Door Latch Malfunction
1. Ignition OFF, disconnect the harness connector at the appropriate A23 door latch assembly.
2. Connect a test lamp between the control circuit terminal 5 and control circuit terminal 10.
3. Pull and release the appropriate exterior door handle, the test lamp should briefly illuminate while the exterior door handle is being pulled.
• If the test lamp is always OFF, test either control circuit for a short to ground or an open/high resistance. If the circuits test normal, replace the K84 keyless entry control module.
• If the test lamp is always ON, test either control circuit for a short to voltage. If the circuits test normal, replace the K84 keyless entry control module.
4. If all circuits test normal, test or replace the A23 door latch assembly.
Repair Instructions
Perform the Diagnostic Repair Verification (Verification Tests) after completing the diagnostic procedure.
* Front Side Door Lock Replacement (Front Side Door Lock Replacement)
* Rear Side Door Lock Replacement (Rear Side Door Lock Replacement)
* Control Module References (Programming and Relearning) for BCM or keyless entry control module replacement, setup and programming