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2018 CX-9 Power Liftgate Not Opening/Closing Reliably

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Mike T. · rep 0 · May 25, 3:37 AM · 1 replies · solved · Question

Vehicle: 2018 Mazda CX-9 Signature

Hello everyone,

I'm having a persistent problem with the power liftgate on my 2018 Mazda CX-9 Signature. It's become very unreliable. Sometimes it opens fine, other times it just beeps a few times and doesn't move, or it opens halfway and then stops. Closing it is also hit or miss.

I've tried resetting it by disconnecting the battery for a bit, but that didn't help. I also made sure there's nothing obstructing the path. I heard there might have been a recall or TSB for CX-9 liftgates, but I'm not sure if it applies to my model year.

Has anyone else had this issue with their 2018 CX-9? Is there a common fix, or am I looking at a costly repair for the motor or struts?

✓ Accepted solution

ClearTheCode Admin

ClearTheCode Team · rep 0 · May 25, 3:37 AM

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ClearTheCode admin answer:

Unreliable operation of the power liftgate on a 2018 Mazda CX-9 is a known concern for some owners. This issue can stem from several common points, including sensor problems, motor issues, or strut integrity.

Common Causes & Steps:

  1. Obstruction Sensors: The liftgate has sensors designed to prevent it from closing on an obstruction. Even minor debris or misaligned rubber seals can sometimes trigger these sensors, causing the liftgate to stop or reverse. Inspect the edges and latch area for anything that might be interfering.
  2. Weak Liftgate Struts: Over time, the gas-filled struts that assist the liftgate can weaken. If they aren't providing enough support, the motor has to work harder, and the system might stop prematurely. This is more common in older vehicles but can happen.
  3. Power Liftgate Motor/Actuator: The electric motor that drives the liftgate can fail or become weak. This often manifests as intermittent operation, slow movement, or the gate stopping mid-cycle. This component typically requires professional replacement.
  4. Wiring Issues: Damaged or frayed wiring in the liftgate harness can lead to intermittent power supply or signal issues to the motor or sensors. This can be challenging to diagnose without specialized tools.
  5. TSBs/Recalls: There have been recalls and TSBs related to power liftgate issues for various Mazda models, though specific ones for the 2018 CX-9's exact symptoms should be checked. For example, some models had issues with water ingress causing corrosion in the liftgate control module. Your VIN can confirm if any apply to your vehicle.

When to See a Shop:

  • Given the intermittent nature and potential for a motor or wiring issue, it's best to have your Mazda dealership or a reputable auto repair shop inspect the liftgate system. They can perform diagnostic tests to pinpoint the exact failure point.
  • There typically aren't standard OBD-II codes for liftgate malfunctions, as it's a body control module (BCM) function. However, the dealership's proprietary diagnostic tools can access specific BCM fault codes related to the liftgate system, which will provide crucial information.
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