Service Information

Cruze

DTC B251A-B251F

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 B251A 01: All Door Uncatch Circuit Short to Battery

DTC B251A 02: All Door Uncatch Circuit Short to Ground

DTC B251B 04: Driver Door Uncatch 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	Short to Ground	Open/High Resistance	Short to Voltage	Signal Performance
Driver Door Uncatch High Control	B250B 02	B251B 04	B250B 01	-
Left Rear Door Unlatch High Control	B251A 02	B251D 04	B251A 01	-
Passenger Door Unlatch High Control	B251A 02	B251C 04	B251A 01	-
Right Rear Door Unlatch High Control	B251A 02	B251E 04	B251A 01	-
Driver Door Uncatch Low Control	B250B 02	B251B 04	B250B 01	-
Left Rear Door Unlatch Low Control	B251A 02	B251D 04	B251A 01	-
Passenger Door Unlatch Low Control	B251A 02	B251C 04	B251A 01	-
Right Rear Door Unlatch Low Control	B251A 02	B251E 04	B251A 01	--

Circuit/System Description

When any exterior door handle is lifted, switched ground signals are sent to the keyless entry control module through the door handle switch signal circuits. Upon receipt of these inputs, the keyless entry control module will check the door lock status of the following inputs:

•	Door unlock switch activation

•	Keyless entry unlock command

•	Passive keyless entry unlock command message is received by the keyless entry control module

Once the enable criteria have been met, the keyless entry control module will supply power and ground to door catch control circuits and the door will release.

Conditions for Running the DTC

Battery voltage is between 9-16 V.

Conditions for Setting the DTC

B251A 01

The keyless entry control module detects a short-circuit to voltage in any door release motor release control low circuit.

B251A 02

The keyless entry control module detects a short-circuit to ground in any door release motor release control low circuit.

B251B 04

The keyless entry control module detects an open in the driver door release motor release control low or high circuit.

B251C 04

The keyless entry control module detects an open in the passenger door release motor release control low or high circuit.

B251D 02

The keyless entry control module detects an open in the left rear door release motor release control low or high circuit.

B251E 04

The keyless entry control module detects an open in the right rear door release motor release control low or high circuit.

Action Taken When the DTC Sets

The keyless entry control module ignores inputs from the exterior door handle switches.

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

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 body control module Driver Door Unlatch and Passenger Door(s) Unlatch with the scan tool. The driver and passenger door catches should unlatch when changing between commanded states.

Circuit/System Testing

Ignition OFF, disconnect the harness connector at the malfunctioning door latch assembly.
Ignition ON, verify that a test lamp does not illuminate between control circuit terminal 5 and ground.

⇒	If the test lamp illuminates, test the control circuit for a short to voltage. If the circuit tests normal, replace the K84 Keyless Entry Control Module.

Verify that a test lamp does not illuminate between control circuit terminal 10 and ground.

⇒	If the test lamp illuminates, test the control circuit for a short to voltage. If the circuit tests normal, replace the K84 Keyless Entry Control Module.

Verify that a test lamp does not illuminate between control circuit terminal 5 and B+.

⇒	If the test lamp illuminates, test the control circuit for a short to ground. If the circuit tests normal, replace the K84 Keyless Entry Control Module.

Verify that a test lamp does not illuminate between control circuit terminal 10 and B+.

⇒	If the test lamp illuminates, test the control circuit for a short to ground. If the circuit tests normal, replace the K84 Keyless Entry Control Module.

Connect a test lamp between the control circuit terminals 5 and 10.
Verify the test lamp illuminates briefly, while pulling the exterior door handle.

⇒	If the test lamp does not illuminate, test the control circuits for an open/high resistance. If the circuits test normal, replace K84 Keyless Entry Control Module.

If all circuits test normal, test or replace the door latch assembly.

Component Testing

Door Catch Assembly Test

Ignition OFF, disconnect the harness connector at the appropriate door latch assembly.
Ignition ON, install a 15 A fused jumper wire between the control terminal listed below and B+:

•	Driver door catch control terminal 10

•	Passenger door catch control terminal 5

•	Left rear door catch control terminal 10

•	Right rear door catch control terminal 5

Momentarily install a jumper wire between the control terminal listed below and ground. The door catch should perform the Unlock function:

•	Driver door catch control terminal 5

•	Passenger door catch control terminal 10

•	Left rear door catch control terminal 5

•	Right rear door catch control terminal 10

⇒	If the function does not perform as specified, replace the door latch assembly.

Reverse the jumper wires; the door catch assembly should perform the Lock function.

⇒	If the function does not perform as specified, replace the door latch assembly.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

•	Front Side Door Catch Replacement

•	Control Module References for keyless entry control module replacement, setup, and programming