If your vehicle is showing power liftgate opens partially and immediately reverses, here are the most likely causes and the parts you'll need to fix each one.
The power liftgate motor relies on the gas struts to help lift the heavy door. If the struts lose their pressurized gas over time, the motor strains under the extra weight, triggering the safety anti-pinch feature and causing it to reverse.
Debris in the liftgate path, a shifted cargo mat, or dry, binding hinges can create physical resistance. The system detects this mechanical drag as an obstacle and reverses to prevent damage.
If the battery was recently disconnected, replaced, or died, the liftgate control module may forget its programmed open and close limits. It reverses because it no longer knows the correct position of the door and defaults to a safety state.
A failing battery can cause a significant voltage drop when the high-draw liftgate motor activates. The computer interprets this sudden drop in power as a motor stall (simulating a pinch) and reverses the door.
The pinch sensors (usually integrated into the weatherstripping along the edges of the liftgate) can become damaged or shorted out, falsely signaling to the computer that an object is trapped in the door.