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2021 Yukon Denali Power Liftgate Malfunction - Not Opening/Closing Reliably

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David L. · rep 0 · May 25, 2:42 AM · 1 replies · solved · Question

Vehicle: 2021 GMC Yukon Denali

Hey GMC community,

I'm having an intermittent but annoying issue with the power liftgate on my 2021 GMC Yukon Denali. Sometimes it works perfectly, opening and closing smoothly with the button, key fob, or even the kick sensor. Other times, it just won't respond, or it will start to open/close and then stop halfway. I've had it refuse to close completely a few times, which is a security concern.

I've checked for obstructions, and there's nothing in the way. It seems completely random. I've tried resetting it by disconnecting the battery for a bit, but the problem eventually comes back. Is this a common issue with the newer Yukon models? I bought this vehicle for its convenience features, and this one is really letting me down.

Before I take it to the dealer, I wanted to see if anyone has experienced this and found a solution, or if there are any known TSBs or recalls for power liftgate issues on the 2021 Yukon. Thanks for any insights!

✓ Accepted solution

ClearTheCode Admin

ClearTheCode Team · rep 0 · May 25, 2:42 AM

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ClearTheCode admin answer:

Intermittent power liftgate malfunctions on vehicles like your 2021 GMC Yukon Denali can be frustrating, especially when they affect convenience and security. These systems are electronically controlled and rely on several components working in harmony.

Common Causes:

  1. Faulty Liftgate Struts/Motors: The power struts contain motors and sensors that can wear out or become intermittent, leading to inconsistent operation.
  2. Sensor Malfunctions: The pinch sensors (designed to stop the gate if an obstruction is detected) or position sensors can become faulty, causing the gate to stop unexpectedly.
  3. Wiring Issues: Damaged or corroded wiring in the liftgate harness can lead to intermittent power or signal loss.
  4. Control Module Glitch: The liftgate control module (LGCM) can sometimes experience software glitches or internal failures.
  5. Weak Key Fob Battery: While less likely if it's also happening with the interior button, a weak key fob battery can sometimes cause intermittent remote operation.

When to See a Shop:

  • Soon: If the liftgate frequently fails to close completely, posing a security risk or exposure to weather.
  • Immediately: If the liftgate becomes completely inoperable or if you notice any strange noises or physical binding when it attempts to operate.

Diagnostics & Potential Solutions:

  1. Diagnostic Scan: A dealership can connect to the vehicle's diagnostic system and check for specific fault codes related to the liftgate control module. These codes can pinpoint which sensor or motor is malfunctioning.
  2. Inspect Wiring Harness: Technicians will inspect the wiring harness that runs into the liftgate for any signs of fraying, pinching, or corrosion.
  3. Test Struts/Motors: The power liftgate struts and their integrated motors can be tested for proper operation and power delivery. If one is weak or failing, it can cause the gate to stop or operate unevenly.
  4. Sensor Calibration/Replacement: The pinch sensors along the edges of the liftgate and any position sensors will be checked. Sometimes, recalibration is needed; other times, replacement is required.
  5. Control Module Check: The liftgate control module itself will be checked for proper communication and operation. Software updates for the module might also be available.
  6. Manual Operation Check: Ensure the manual override (if applicable) works smoothly, which can sometimes help diagnose mechanical binding vs. electrical issues.

Since this is a newer vehicle, it's likely still under warranty. Documenting the issues with videos can be very helpful when explaining the problem to the service technician.

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