Service Information

Volt

DTC B2500

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 B2500 00: Driver Exterior Unlock Switch Circuit

Diagnostic Fault Information

Circuit	Short to Ground	Open/High Resistance	Short to Voltage	Signal Performance
Driver Door Key Switch Signal	B2500 00	1	1	--
Driver Door Latch Ground	--	1	--	--
1. Key Cylinder Switch Inoperative

The driver window switch monitors the voltage level of the key switch unlock signal circuit. When the key is inserted into the driver door key cylinder and turned to the Unlock position, a switch within the driver door latch closes causing the voltage to drop within the key switch unlock signal circuit. The driver window switch will detect the drop in voltage and will send a serial data message to the BCM commanding all the doors to unlock.

Conditions for Running the DTC

The system voltage is 9-16 V

Conditions for Setting the DTC

The BCM detects a short to ground on the driver door key switch signal circuit.

Action Taken When the DTC Sets

The BCM will ignore the unlock command from the key cylinder switch.

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 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

Insert the key into the driver door lock cylinder, turn the key to the unlock position while observing the scan tool BCM Driver Door Key Unlock Switch parameter, the value should change from Inactive to Active.

Circuit/System Testing

Vehicle OFF, disconnect the harness connector at the A23D door latch assembly-driver.
Vehicle in Service Mode, verify the scan tool Driver Door Key Unlock Switch parameter is Inactive.

⇒	If not the specified value, test the signal circuit terminal 9 for a short to ground. If the circuits test normal, replace the S79D window switch - driver.

If all circuits tests normal, test or replace the A23D door latch assembly-driver.

Component Testing

Vehicle OFF, disconnect the harness connector at the A23D door latch assembly-driver.
Test for infinite resistance between terminal 8 and terminal 9 with the switch in the open position.

⇒	If not the specified value, replace the A23D door latch assembly-driver.

Test for less than 2 Ω between terminal 8 and terminal 9 with the switch in the unlock position.

⇒	If greater than the specified range, replace the A23D door latch assembly-driver.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

•	Front Side Door Window and Multifunction Switch Replacement

•	Front Side Door Lock Replacement