My rear liftgate was forced down and ever since when it opens it immediately closes unless I stop it?

Tiny
AARON BISHOP
  • MEMBER
  • 2014 JEEP GRAND CHEROKEE
  • 5.7L
  • V8
  • 4WD
  • AUTOMATIC
  • 179,000 MILES
My rear liftgate was forced down and ever since when it opens it immediately closes unless I stop it. Then it will stay up and close normal when I press the button. I hooked up my launch scanner and see one side pitch sensor is 2.44 volts and the other is 4.77 volts. Also throwing a B195F-12 code. Any help would be great and how do I find out what the voltage should be on the sensors? I'm thinking the one with 2.44 is probably broken and needs to be replaced.
Tuesday, May 2nd, 2023 AT 12:41 PM

3 Replies

Tiny
CARADIODOC
  • MECHANIC
  • 33,871 POSTS
With engine sensors, position sensors are normally fed with 5.0 volts and ground, then they develop a signal voltage between roughly 0.5 and 4.5 volts. Anything outside that range is what gets detected as a defect and sets a diagnostic fault code. It looks like these work the same way, so the one with 2.44 volts would be the one working properly.

I've only worked on this system once for this problem. Start by looking through this diagnostic chart. I have the wiring diagrams too but will need a little time to format them. See how far you can get with this for now, and let me know.
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Tuesday, May 2nd, 2023 AT 10:27 PM
Tiny
CARADIODOC
  • MECHANIC
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Were you able to make any progress with that chart? I have the same system on my 2014 Caravan. When looking at the computer data, I don't have any listings for position sensor voltages like those you found. The two position sensors are shown, but with "number of clicks".

The one I helped my friend with was on a Caravan rebuilder a few years ago. It did exactly as what you described, but we found it was the transmission range sensor that was out of adjustment. It still performed the neutral safety switch function correctly and the starter system worked, but the Liftgate Computer was seeing it was not in "park".

I'm adding the diagram for this system below, if that will help. The two position sensor circuits are shown at the right side of the third diagram.

Please keep me updated on your progress.
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Wednesday, May 3rd, 2023 AT 4:18 PM
Tiny
CARADIODOC
  • MECHANIC
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I was reminded that forcing the liftgate to stop partway open causes the computer to lose track of its position. There's two relearn procedures that may need to be done with the scanner. Before you do that, disconnect the battery for up to a half hour. When reconnected, the system should go through a learning cycle on its own.
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Wednesday, May 3rd, 2023 AT 7:54 PM

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