B1955-POWER LIFTGATE LATCH RELEASE OVERCURRENT
For a complete wiring diagram Refer to Section 8W
- When Monitored:
Whenever the power liftgate is performing a releasing operation.
- Set Condition:
The latch motor stall current of over seven amps has been detected for over 500ms. with no pawl or ratchet failure
| Possible Causes |
| BINDING LIFTGATE |
| (Q84) LIFTGATE LATCH CINCH DRIVER CIRCUIT SHORT TO VOLTAGE |
| (Q76) LATCH SECONDARY POSITION SENSE CIRCUIT OPEN |
| (Q85) LIFTGATE LATCH RELEASE CIRCUIT SHORT TO VOLTAGE |
| (Q901) LOGIC GROUND CIRCUIT OPEN |
| (G78) LIFTGATE AJAR SWITCH SENSE CIRCUIT OPEN |
| (Q60) LIFTGATE PAWL SWITCH SENSE CIRCUIT OPEN |
| LATCH ASSEMBLY |
Diagnostic Test
1. DTC PRESENTNOTE: If there are any other Power Liftgate DTCs present, repair them before proceeding with this test.
Ensure the liftgate is closed and with the scan tool, run the “Latch Home Position Test” before proceeding to ensure the latch is positioned correctly.
With the scan tool, record and erase DTCs.
Turn the ignition off, wait 10 seconds, then turn the ignition on.
Operate the power liftgate several times if possible.
With the scan tool, read ACTIVE DTCs.
Does the scan tool display B1955–POWER LIFTGATE LATCH RELEASE OVERCURRENT?
Yes
- Go To2
No
- Using the wiring diagram/schematic as a guide, inspect the wiring and connectors for an intermittent condition. Operate the liftgate several times and check for any binding or other obstructions.
- Perform BODY VERIFICATION TEST - VER 1. (Refer to 8 - ELECTRICAL/ELECTRONIC CONTROL MODULES - STANDARD PROCEDURE).
2. BINDING LIFTGATE
Examine the liftgate for proper alignment, worn or binding hinges, weak liftgate prop assembly, loose/hard weatherstrip, and track assembly for wear or anything that would cause an obstruction to proper operation.
If necessary manually operate the power liftgate on a known good vehicle and notice the effort needed to open and close for comparison.
Especially notice the effort needed to unlatch and close the liftgate.
Were there any mechanical problems found?
Yes
- Refer to Service information for the related symptom(s).
- Perform BODY VERIFICATION TEST - VER 1. (Refer to 8 - ELECTRICAL/ELECTRONIC CONTROL MODULES - STANDARD PROCEDURE).
No
- Go To3
3. CHECK THE (Q84) LIFTGATE LATCH CINCH DRIVER CIRCUIT AND THE (Q85) LIFTGATE LATCH RELEASE DRIVER CIRCUIT FOR A SHORT TO VOLTAGE
Turn the ignition off.
Disconnect the Power Liftgate Module C2 harness connector.
Disconnect the Power Liftgate Latch harness connector.
Turn the ignition on.
Measure the voltage of the (Q84) Liftgate Latch Cinch Driver circuit and the (Q85) Liftgate Latch Release Driver circuit.
Is there any voltage present?
Yes
- Repair the (Q84) Liftgate Latch Cinch Driver circuit or the (Q85) Liftgate Latch Release Driver circuit for a short to voltage.
No
- Go To 4
4. (Q76) LATCH SECONDARY POSITION SENSE CIRCUIT OPEN
Measure the resistance of the (Q76) Latch Secondary Position Sense circuit between the Power Liftgate Module C2 harness connector and the Power Liftgate Latch harness connector.
Is the resistance below 2.0 ohms?
Yes
- Go To5.
No
- Repair the (Q76) Latch Secondary Position Sense wire for an open.
- Perform BODY VERIFICATION TEST - VER 1. (Refer to 8 - ELECTRICAL/ELECTRONIC CONTROL MODULES - STANDARD PROCEDURE).
5. CHECK THE (Q901) LOGIC GROUND CIRCUIT FOR AN OPEN
Measure the resistance of the (Q901) Logic Ground circuit between the Power Liftgate Module C2 harness connector and the Power Liftgate Latch harness connector.
Is the resistance below 2.0 ohms?
Yes
- Go To6
No
- Repair the (Q901) Logic Ground circuit for an open.
- Perform BODY VERIFICATION TEST - VER 1. (Refer to 8 - ELECTRICAL/ELECTRONIC CONTROL MODULES - STANDARD PROCEDURE).
6. CHECK THE (G78) LIFTGATE AJAR SWITCH SENSE CHECK FOR OPEN
Measure the resistance of the (G78) Liftgate Ajar Switch Sense circuit between the Power Liftgate Module C2 harness connector and the Power Liftgate Latch harness connector.
Is the resistance below 2.0 ohms?
Yes
- Go To 7
No
- Repair the (G78) Liftgate Ajar Switch Sense wire for an open.
- Perform BODY VERIFICATION TEST - VER 1. (Refer to 8 - ELECTRICAL/ELECTRONIC CONTROL MODULES - STANDARD PROCEDURE).
7. CHECK THE (Q60) LIFTGATE PAWL SWITCH SENSE CIRCUIT FOR AN OPEN
Measure the resistance of the (Q60) Liftgate Pawl Switch Sense circuit between the Power Liftgate Module C2 harness connector and the Power Liftgate Latch harness connector.
Wiggle the harness while observing the ohmmeter.
Is the resistance below 2.0 ohms?
Yes
- Replace the Power Liftgate Latch Assembly in accordance with service information.
- Perform BODY VERIFICATION TEST - VER 1. (Refer to 8 - ELECTRICAL/ELECTRONIC CONTROL MODULES - STANDARD PROCEDURE).
No
- Repair the (Q60) Liftgate Pawl Switch Sense circuit for an open.
- Perform BODY VERIFICATION TEST - VER 1. (Refer to 8 - ELECTRICAL/ELECTRONIC CONTROL MODULES - STANDARD PROCEDURE).