Diagnostic Routine L

Diagnostic Routine L

Diagnostic Overview

B2908

Refer to Wiring Diagram Set 109 for schematic and connector information Electrical Diagrams.

Normal Operations and Fault Conditions

The LTM (Liftgate/Trunk Module) monitors the detent switch, secondary forkbolt switch and the primary forkbolt switch to determine the status of the liftgate latch (primary latch, secondary latch, or fully unlatched). All 3 switches are internal to the power liftgate latch. The LTM (Liftgate/Trunk Module) supplies each of the switches a reference voltage signal to each one of the switches. Depending upon the latch state, each individual switch is either closed and supplying a ground to the module on one of the circuits or the switch is open.

The detent switch only changes state during latch movement. While monitoring the detent switch PID (Parameter Identification), it is important to carefully monitor it during latch movement or monitor the PID (Parameter Identification) while manually rotating the latch.

DTC Fault Trigger Conditions






Pinpoint Test

1. CHECK THE OPERATION OF THE DETENT AND FORKBOLT SWITCHES

1. Ignition OFF.

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

3. Place the liftgate in the fully unlatched position. REFER to Liftgate Latch Manual Release .

4. Measure:





5. Record the test results.

6. Place the liftgate in the primary latch position.

7. Measure:





8. NOTE: If the detent switch resistance measured is less than 5 ohms in the fully unlatched position, manually rotate the forkbolt to the latched position while measuring the resistance.
Record the test results.

9. Compare the results with the table below.





Do the resistance values agree with the table?








2. CHECK THE DETENT AND FORKBOLT SWITCH GROUND CIRCUIT

1. Disconnect: Power Liftgate Latch.

2. Measure:








Is the resistance less than 3 ohms?








3. CHECK THE DETENT AND FORKBOLT SWITCH CIRCUITS FOR A SHORT TO GROUND

1. Measure:





Is the resistance greater than 10,000 ohms?








4. CHECK THE DETENT AND FORKBOLT SWITCH CIRCUITS FOR AN OPEN

1. Measure:








Are the resistances less than 3 ohms?








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

1. Ignition OFF.

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

3. Repair:

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

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

5. Operate the system and determine if the concern is still present.

Is the concern still present?