Service Information

Cruze

DTC B0685

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 B0685 02: Security Indicator Circuit Short to Ground

Diagnostic Fault Information

Circuit	Short to Ground	Open/High Resistance	Short to Voltage	Signal Performance
Security LED Control	B0685 02	1	1	--
Ground	--	1	--	--
1. Security Indicator Malfunction

The security LED is controlled by the body control module (BCM) based on commands from the content theft deterrent system. The security LED is located in the dash as part of the ambient light sensor and is supplied ground at all times. When the content theft deterrent system requests the LED be commanded ON, the BCM applies voltage to the security indicator control circuit, illuminating the LED.

Conditions for Running the DTC

The system voltage is at least 9 V and no more than 16 V.

Conditions for Setting the DTC

•	The BCM detects a short to ground on the security indicator control circuit.

•	The above condition exists for 1 s.

Action Taken When the DTC Sets

Security LED output is disabled.

Conditions for Clearing the DTC

•	A current DTC is cleared when the conditions for setting the DTC are no longer present.

•	A history DTC will clear after 40 malfunction free 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 OFF. Arm the content theft deterrent system.
Verify that the security LED should illuminate and/or flash during the arming sequence.
If not OK

Refer to Circuit/System Testing.
If OK
Verify DTC B0685 does not set.
If DTC B0685 does set

Refer to Circuit/System testing.
If DTC does not set
All OK.

Circuit/System Testing

Ignition OFF, disconnect the harness connector at the B10B Ambient Light/Sunload Sensor.
Test for less than 10 Ω between the ground circuit terminal 6 and ground.
If 5 Ω or greater

2.1.	Ignition OFF.

2.2.	Test for less than 2 Ω in the ground circuit end to end.

If 2 Ω or greater, repair the open/high resistance in the circuit.
If less than 2 Ω, repair the open/high resistance in the ground connection.
If less than 5 Ω
Ignition ON, connect a test lamp between the control circuit terminal 1 and the ground circuit terminal 6.
Verify the test lamp turns ON and OFF when Commanding the Security Indicator Lamp ON and OFF with a scan tool.
If the test lamp is always OFF

4.1.	Ignition OFF, disconnect the harness connector at the K9 Body Control Module.

4.2.	Test for infinite resistance between the control circuit and ground.

If less than infinite resistance, repair the short to ground on the circuit.
If infinite resistance

4.3.	Test for less than 2 Ω in the control circuit end to end.

If 2 Ω or greater, repair the open/high resistance in the circuit.
If less than 2 Ω, replace the K9 Body Control Module.
If the test lamp is always ON

4.1.	Ignition OFF, disconnect the harness connector at the K9 Body Control Module.

4.2.	Ignition ON, test for less than 1 V between the control circuit and ground.

If 1 V or greater, repair the short to voltage on the circuit.
If less than 1 V, replace the K9 Body Control Module.
If the test lamp turns ON and OFF
Replace the B10B Ambient Light/Sunload Sensor.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

Control Module References for BCM replacement, setup, and programming