Diagnostic Routine F
Diagnostic Routine F
Diagnostic Overview
The Liftgate Latch Release Is Inoperative
Refer to Wiring Diagram Set 109 for schematic and connector information Electrical Diagrams.
Refer to Wiring Diagram Set 117 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 release switch or RKE (Remote Keyless Entry) transmitter (vehicles with power liftgate), the BCM (Body Control Module) supplies voltage to the liftgate latch or the LTM (Liftgate/Trunk Module) (vehicles with power liftgate). The liftgate latch has a dedicated ground circuit.
The BCM (Body Control Module) sends a voltage signal to the liftgate release switch through the input circuit. When the liftgate release switch is pressed, the voltage signal is routed to ground, signaling the BCM (Body Control Module) to release the liftgate. The liftgate release switch has a dedicated ground circuit.
REFER to DESCRIPTION AND OPERATION for information on the power liftgate operation.
NOTE: If the liftgate latch fails to open electronically, it can be opened with the mechanical release. REFER to Liftgate Latch Manual Release .
DTC Fault Trigger Conditions
Visual Inspection and Diagnostic Pre-checks
- BCM (Body Control Module) fuse 25 (15A)
- Liftgate 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 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 BCM (Body Control Module) AND LTM (Liftgate/Trunk Module) DTCs (Diagnostic Trouble Codes) FROM THE SELF-TESTS
1. Using a scan tool, perform the BCM (Body Control Module) self-test.
2. Using a scan tool, perform the LTM (Liftgate/Trunk Module) self-test.
Are any DTCs (Diagnostic Trouble Codes) recorded?
2. REPEAT THE BCM (Body Control Module) SELF-TEST
1. Disconnect: Liftgate Release Switch.
2. Using a scan tool, clear the BCM (Body Control Module) DTCs (Diagnostic Trouble Codes).
3. Using a scan tool, perform the BCM (Body Control Module) self-test.
Is DTC (Diagnostic Trouble Code) B12E8:11 recorded?
3. CHECK THE LIFTGATE RELEASE SWITCH INPUT CIRCUIT FOR A SHORT TO GROUND
1. Ignition OFF.
2. Disconnect BCM (Body Control Module) C2280C.
3. Measure:
Is the resistance greater than 10,000 ohms?
4. CHECK THE EXTERIOR LIFTGATE RELEASE SWITCH
1. Unlock the doors with the door lock control switch.
2. Disconnect: Liftgate Release Switch.
3. Connect a fused jumper wire:
Does the liftgate release?
5. CHECK FOR BCM (Body Control Module) DTCs (Diagnostic Trouble Codes) FROM THE SELF-TEST
1. Using a scan tool, clear the BCM (Body Control Module) DTCs (Diagnostic Trouble Codes).
2. Using a scan tool, perform the BCM (Body Control Module) self-test with the jumper wire still connected.
Is DTC (Diagnostic Trouble Code) B12E8:11 retrieved?
6. CHECK THE LIFTGATE RELEASE SWITCH GROUND CIRCUIT FOR AN OPEN
1. Using a scan tool, clear the BCM (Body Control Module) DTCs (Diagnostic Trouble Codes).
2. Connect a fused jumper wire:
3. Using a scan tool, perform the BCM (Body Control Module) self-test.
Is DTC (Diagnostic Trouble Code) B12E8:11 retrieved?
7. CHECK THE LIFTGATE RELEASE SWITCH INPUT CIRCUIT FOR AN OPEN
1. Ignition OFF.
2. Disconnect BCM (Body Control Module) C2280C.
3. Measure:
Is the resistance less than 3 ohms?
8. CHECK FOR VOLTAGE TO THE LIFTGATE LATCH OR LTM (Liftgate/Trunk Module)
1. Ignition OFF.
2. Disconnect: Liftgate Latch (manual liftgate).
3. Disconnect: LTM (Liftgate/Trunk Module) C4174B (power liftgate).
4. Ignition ON.
5. For manual liftgate, measure:
6. For power liftgate, measure:
Is any voltage present?
9. CHECK FOR A SHORT TO VOLTAGE
1. Ignition OFF.
2. Disconnect BCM (Body Control Module) C2280D.
3. Ignition ON.
4. Measure:
Is any voltage present?
10. CHECK FOR BCM (Body Control Module) OUTPUT
NOTE: The BCM (Body Control Module) only supplies voltage for the liftgate latch release momentarily. It is important to monitor the test light while activating the liftgate release switch.
1. Ignition OFF.
2. Connect: Liftgate Release Switch.
3. Unlock the doors with the door lock control switch.
4. For manual liftgate, press the liftgate release switch while monitoring the test light.
5. For power liftgate, press the liftgate release switch while monitoring the test light.
Does the test light momentarily illuminate?
11. CHECK THE LIFTGATE RELEASE OUTPUT CIRCUIT FOR AN OPEN
1. Disconnect: BCM (Body Control Module) C2280D.
2. For manual liftgate, measure:
3. For power liftgate, measure:
Is the resistance less than 3 ohms?
12. CHECK THE LIFTGATE LATCH GROUND CIRCUIT FOR AN OPEN
1. Measure:
Is the resistance less than 3 ohms?
13. 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 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?
14. 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 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 BCM (Body Control 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?
