Service Information

Volt

DTC B3930

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 B3930 02: Child Security Lock Motors Circuit Short to Ground

Diagnostic Fault Information

Circuit	Short to Ground	Open/High Resistance	Short to Voltage	Signal Performance
Door Lock Security Relay Control	B3930 02	1	1	--
Under-bonnet Fuse Block Ground	--	1	--	--
1. Child Security Door Lock Malfunction

The child door lockout switch is on the driver door lock/window switch and controls the child locks on the rear doors as well as the rear window switches. When the BCM receives a command from the window lockout switch, it will apply voltage to the door lock security relay coil, this will energise the relay and the contact within the relay will then direct the voltage to lock the left rear and right rear child locks and then isolate them from the normal door lock system to prevent the rear doors from being opened by using the interior rear door handles.

Conditions for Running the DTC

Battery voltage must be between 9-16 V.

Conditions for Setting the DTC

The BCM detects a short to ground in the child security lock relay circuit.

Action Taken When the DTC Sets

The interior rear door handles will continue to function when commanded to lockout.

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

Vehicle in Service Mode, with all the doors locked, command the child security lockout by pressing the window lockout switch on the S79D window switch-driver, the interior rear door handles should not open the doors when used.

Circuit/System Testing

Vehicle OFF, disconnect the X3 harness connector at the X50A fuse block-under-bonnet.
Test for less than 10 Ω between the ground circuit terminal 48 and ground.

⇒	If greater than the specified range, test the ground circuit for an open/high resistance.

Vehicle OFF, connect the X3 harness connector and disconnect the X1 harness connector at the X50A fuse block-under-bonnet.
Connect a test lamp between the control circuit terminal 36 and ground.
Vehicle in Service Mode, command the child security lockout by pressing the window lockout switch on the S79D window switch-driver. The test lamp should turn ON and OFF when changing between the commanded states.

⇒	If the test lamp is always OFF, test the control circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the K9 BCM.

⇒	If the test lamp is always ON, test the control circuit for a short to voltage. If the circuit tests normal, replace the K9 BCM.

If all circuits test normal, replace the X50A fuse block-under-bonnet.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

•	Fuse Block Replacement

•	Control Module References for BCM replacement, programming and setup