Lighting Control Module (LCM)

Lighting Control Module (LCM)

Pinpoint Test C: DTC B1676

Refer to Wiring Diagram Set 13, Power Distribution/SJB for schematic and connector information. Diagrams By Number

Normal Operation

The Lighting Control Module (LCM) monitors the voltage from the battery to determine if it goes above or below specific thresholds and sets DTC B1676 in continuous memory and on-demand if the LCM detects high battery voltage above 16 volts on circuit 221 (OG/WH).

- DTC B1676 (Battery Pack Voltage Out Of Range) - a continuous memory or an on-demand DTC that sets when the LCM detects battery voltage out of range for at least 2 minutes. A minimum of (+/-) 24 seconds must elapse before this DTC is recorded. Battery voltage is out of range if it is less than 8.5 volts (+/- 1.0V) or greater than 17 volts (+/-1.5V).

This pinpoint test is intended to diagnose the following:

- Charging system concern
- LCM



PINPOINT TEST C: DTC B1676

NOTE: DTC B1676 may be stored in the module memory due to previous battery charging or vehicle jump starting events.

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C1 CHECK FOR DTC B1317, B1676 OR P0563 SET IN OTHER MODULES


- Ignition ON.
- Enter the following diagnostic mode on the scan tool: (All CMDTCs) Self-Test.
- Retrieve the continuous memory DTCs from all modules.
- Is DTC B1317, B1676 or P0563 (PCM) set in more than one module?

Yes
REFER to Charging System to diagnose an overcharging condition.

No
GO to C2.

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C2 CHECK THE BATTERY VOLTAGE


- Turn off all interior/exterior lights and accessories.
- Start and run the engine at approximately 2,000 rpm for 3 minutes while monitoring the battery voltage.
- Does the battery voltage rise to 15.5 volts or higher?

Yes
REFER to Charging System to diagnose an overcharging condition.

No
GO to C3.

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C3 RECHECK FOR DTC B1676


- Turn the engine off.
- Ignition ON.
- Enter the following diagnostic mode on the scan tool: LCM Self-Test.
- Clear the continuous memory DTCs.
- Carry out the LCM self-test.
- Is DTC B1676 present?

Yes
INSTALL a new LCM. REFER to Lighting Control Module (LCM) Service and Repair. TEST the system for normal operation.

No
The system is operating normally at this time. The DTC may have been set previously during battery charging or while jump starting the vehicle.

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