Service Information

Volt

Rear Hatch/Gate Ajar Indicator Malfunction

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.

Diagnostic Fault Information

Circuit	Short to Ground	Open/High Resistance	Short to Voltage	Signal Performance
Rear Compartment Lid Ajar Switch Signal	1	2	2	--
Tailgate Latch Ground	--	3	--	--
1. Hatch Ajar Message Always Illuminated 2. Hatch Ajar Message Inoperative 3. Hatch Release Inoperative

Circuit

Short to Ground

Open/High Resistance

Short to Voltage

Signal Performance

Rear Compartment Lid Ajar Switch Signal

Tailgate Latch Ground

1. Hatch Ajar Message Always Illuminated

2. Hatch Ajar Message Inoperative

3. Hatch Release Inoperative

The body control module (BCM) supplies a 12V signal to the rear compartment lid ajar switch signal circuit. When the tailgate latch releases the rear hatch, the rear compartment lid ajar switch, which is internal to the tailgate latch, is supplied with ground which causes the rear hatch/gate ajar switch signal circuit to be pulled low. The BCM interprets this and communicates via serial data to the driver information center which will display the Hatch Open message.

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

Vehicle in Service Mode, observe the scan tool Rear Closure Ajar Switch parameter while opening and closing the rear hatch. The parameter should change between Inactive and Active.

Circuit/System Testing

Vehicle OFF, disconnect the harness connector at the A23C tailgate latch assembly.
Vehicle in Service Mode, verify the scan tool Rear Closure Ajar Switch parameter is Inactive.

⇒	If not the specified value, test the signal circuit terminal 2 for a short to ground. If the circuit tests normal, replace the K9 BCM.

Install a 3 A fused jumper wire between the signal circuit terminal 2 and ground. Verify the scan tool Rear Closure Ajar Switch parameter is Active.

⇒	If not the specified value, test the signal circuit for a short to voltage or and open/high resistance. If the circuit tests normal, replace the K9 BCM.

If all circuits test normal, test or replace the A23C tailgate latch assembly.

Component Testing

Static Test

Vehicle OFF, disconnect the harness connector at the A23C tailgate latch assembly.
Test for infinite resistance between the signal terminal 2 and the ground terminal 1 with the switch in the open position.

⇒	If not the specified value, replace the A23C tailgate latch assembly.

Test for less than 2 Ω between the signal terminal 2 and the ground terminal 1 with the switch in the closed position.

⇒	If greater than the specified range, replace the A23C tailgate latch assembly.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

•	Tailgate Latch Replacement

•	Control Module References for BCM replacement, programming and setup