Diagnostic Routine N

Diagnostic Routine N

Diagnostic Overview

The Liftgate Trunk Module (LTM) 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 109 for schematic and connector information Electrical Diagrams.

Normal Operation and Fault Conditions

The LTM (Liftgate/Trunk Module) communicates with the scan tool through the MS-CAN (Medium Speed Controller Area Network).

Visual Inspection and Diagnostic Pre-checks

Verify BJB (Battery Junction Box) fuse 7 (30A) and BCM (Body Control Module) fuse 9 (10A) are OK.

Pinpoint Test

1. CHECK THE LTM (Liftgate/Trunk Module) VOLTAGE SUPPLY CIRCUITS FOR AN OPEN

1. Ignition OFF.

2. Disconnect: LTM (Liftgate/Trunk Module) C4174A.

3. Ignition ON.

4. Measure:








Are the voltages greater than 11 volts?






2. CHECK THE LTM (Liftgate/Trunk Module) GROUND CIRCUIT FOR AN OPEN

1. Ignition OFF.

2. Measure:








Is the resistance less than 3 ohms?






3. CHECK THE MS-CAN (Medium Speed Controller Area Network) CIRCUITS BETWEEN THE LTM (Liftgate/Trunk Module) AND THE DLC (Data Link Connector) FOR AN OPEN

1. Disconnect: LTM (Liftgate/Trunk Module) C4174B.

2. Measure:





Are the resistances less than 3 ohms?






4. CHECK FOR CORRECT LTM (Liftgate/Trunk Module) OPERATION

1. Ignition OFF.

2. Disconnect and inspect the LTM (Liftgate/Trunk Module) connectors.

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 LTM (Liftgate/Trunk Module) connectors. Make sure they seat and latch correctly.

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

Is the concern still present?