Diagnostic Routine Z

Diagnostic Routine Z

Diagnostic Overview

The Liftgate or Luggage Compartment Lid Latch Release is Inoperative

Refer to Wiring Diagram Set 113 for schematic and connector information Electrical Diagrams.

Normal Operations and Fault Conditions

When the BCM (Body Control Module) receives an open request from the liftgate or luggage compartment lid switch or a RKE (Remote Keyless Entry) transmitter, the BCM (Body Control Module) supplies voltage to the liftgate or luggage compartment lid latch which releases the latch. The latch has a dedicated ground circuit.

The BCM (Body Control Module) sends a voltage signal to the liftgate or luggage compartment lid release switch through the input circuit. When the release switch is pressed, the voltage signal is routed to ground, signaling the BCM (Body Control Module) to release the liftgate or luggage compartment lid. The release switch has a dedicated ground circuit. The BCM (Body Control Module) disregards the input from the switch and does not release the liftgate or luggage compartment lid if the doors are locked.

DTC Fault Trigger Conditions






Visual Inspection and Diagnostic Pre-checks

- Inspect the BCM (Body Control Module) fuse 65 (10A).

- Inspect the liftgate or luggage compartment lid release switch.

Special Tool(s)






Pinpoint Test

NOTICE: The following Pinpoint Test uses a test light to simulate normal circuit loads. Use only the test lamp recommended in the Special Tools table at the beginning of this system or electrical equivalent. To avoid connector terminal damage, use the Rotunda Flex Probe kit for the test light probe connection to the vehicle. Do not use the test lamp probe directly on any connector.

1. RETRIEVE THE RECORDED BCM (Body Control Module) DTCs (Diagnostic Trouble Codes) FROM THE SELF-TEST

1. Ignition ON.

2. Using a scan tool, perform the BCM (Body Control Module) self-test.

Is DTC (Diagnostic Trouble Code) B12E8:11or B12E8:23 present?






2. REPEAT THE BCM (Body Control Module) SELF-TEST

1. Disconnect: Liftgate or Luggage Compartment Lid Release Switch.

2. Using a scan tool, clear the BCM (Body Control Module) DTCs (Diagnostic Trouble Codes) and repeat the self-test.

Is DTC (Diagnostic Trouble Code) B12E8:11or B12E8:23 present?






3. CHECK THE LIFTGATE OR LUGGAGE COMPARTMENT LID RELEASE INPUT CIRCUIT FOR A SHORT TO GROUND

1. Ignition OFF.

2. Disconnect: BCM (Body Control Module) C2280B.

3. Measure:





Is the resistance greater than 10,000 ohms?






4. CARRY OUT THE BCM (Body Control Module) TRUNK/LIFTGATE RELEASE OUTPUT (TRNK/LG_RLS) ACTIVE COMMAND USING THE SCAN TOOL

1. Using a scan tool, view BCM (Body Control Module) PIDs (Parameter Identifications).

2. Active command the BCM (Body Control Module) PID (Parameter Identification) TRNK/LG_RLS.

Does the liftgate or luggage compartment lid release?






5. CHECK THE RELEASE SWITCH

1. Disconnect: Liftgate or Luggage Compartment Lid Release Switch.

2. Connect a fused jumper wire:





Does the liftgate or luggage compartment lid release?






6. CHECK THE RELEASE SWITCH GROUND CIRCUIT FOR AN OPEN

1. Connect a fused jumper wire:





Does the liftgate or luggage compartment lid release?






7. CHECK THE RELEASE SWITCH INPUT CIRCUIT FOR AN OPEN

1. Ignition OFF.

2. Disconnect: BCM (Body Control Module) C2280B.

3. Measure:





Is the resistance less than 3 ohms?






8. CHECK FOR VOLTAGE TO THE LUGGAGE COMPARTMENT LID LATCH USING THE BCM (Body Control Module) TRUNK/LIFTGATE RELEASE OUTPUT (TRNK/LG_RLS) PID (Parameter Identification)

1. Using a scan tool, view BCM (Body Control Module) PIDs (Parameter Identifications).

2. Active command the BCM (Body Control Module) PID (Parameter Identification) TRNK/LG_RLS.

3. NOTE: The BCM (Body Control Module) only supplies voltage to the liftgate or luggage compartment lid latch momentarily. It is important to monitor the test light while active commanding the latch to release.
Monitor the test light.





Does the test light momentarily illuminate?






9. CHECK THE LATCH GROUND CIRCUIT FOR AN OPEN USING THE TRUNK/LIFTGATE RELEASE OUTPUT (TRNK/LG_RLS) PID (Parameter Identification)

1. Using a scan tool, view BCM (Body Control Module) PIDs (Parameter Identifications).

2. Active command the BCM (Body Control Module) PID (Parameter Identification) TRNK/LG_RLS.

3. NOTE: The BCM (Body Control Module) only supplies voltage to the liftgate or luggage compartment lid latch momentarily. It is important to monitor the test light while active commanding the latch to release.
Monitor the test light.





Does the test light momentarily illuminate?






10. CHECK THE LATCH RELEASE OUTPUT CIRCUIT FOR AN OPEN

1. Ignition OFF.

2. Disconnect: BCM (Body Control Module) C2280E.

3. Measure:





Is the resistance less than 3 ohms?






11. CHECK FOR CORRECT BCM (Body Control Module) OPERATION

1. Ignition OFF.

2. Disconnect and inspect all BCM (Body Control Module) connectors.

3. Repair:

- corrosion (install new connectors 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 BCM (Body Control Module) connectors and make sure they seat and latch correctly.

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

Is the concern still present?