Diagnostic Routine M

Diagnostic Routine M

Diagnostic Overview

The Front Lighting Control Module (FLM) Does Not Respond To The Scan Tool

Refer to Wiring Diagram Set 14 for schematic and connector information Electrical Diagrams.

Refer to Wiring Diagram Set 85 for schematic and connector information Electrical Diagrams.

Normal Operation and Fault Conditions

The FLM (Front Lighting Control Module) communicates with the scan tool through the HS-CAN (High Speed Controller Area Network).

Visual Inspection and Diagnostic Pre-checks

Verify BCM (Body Control Module) fuse 23 (15A) is OK.

Pinpoint Test

1. CHECK THE FLM (Front Lighting Control Module) VOLTAGE SUPPLY CIRCUIT FOR AN OPEN

1. Ignition OFF.

2. Disconnect: FLM (Front Lighting Control Module).

3. Ignition ON.

4. Measure:





Is the voltage greater than 11 volts?






2. CHECK THE FLM (Front Lighting Control Module) GROUND CIRCUIT FOR AN OPEN

1. Ignition OFF.

2. Measure:





Is the resistance less than 3 ohms?






3. CHECK THE HS-CAN (High Speed Controller Area Network) CIRCUITS BETWEEN THE FLM (Front Lighting Control Module) AND THE DLC (Data Link Connector) FOR AN OPEN

1. Measure:





Are the resistances less than 3 ohms?






4. CHECK FOR CORRECT FLM (Front Lighting Control Module) OPERATION

1. Ignition OFF.

2. Disconnect and inspect the FLM (Front Lighting Control Module) connector.

3. Repair:

- corrosion (replace connector or terminals- clean module pins)
- damaged or bent pins- replace terminals/pins
- pushed-out pins- replace pins as necessary

4. Reconnect the FLM (Front Lighting Control Module) connector. Make sure it seats and latches correctly.

5. Operate the system and verify the concern is still present.

Is the concern still present?