[Doug Schmidt]

Seems like the same problem listed here, (Rear hatch won't stay latched), but that question was never answered.

This problem started 2 weeks ago. No obvious changes to the car were made.

Whenever the engine is started, the rear hatch automatically unlocks. The physical latch remains closed, so the hatch doesn't completely open up. But it just rattles loose. Not fully open. Not fully closed. (Half-pregnant?)

It seems like an electronic decision gets made on engine startup to release the soft lock of the hatch, but I don't know why or what to diagnose further.

The are no obvious loose parts or wires, no borked fuses, no OBD2 codes showing a fault, and the engine battery is quite new and a decent voltage.

The keyfob doesn't even have a remote trunk release button, so it can't be something from the fob.

Any ideas where I should look next or what I can troubleshoot? My partner is getting tired of having to get out of the car and manually re-open and close the hatch to secure it before driving.

 

[Keith Wagner]

At what point in the start cycle does the hatch unlock?
Key on?
Engine start?
After engine start?

I would also suggest that you go to nico club and download the Factory Service Manual. It may help give some insight on the issue.
www.nicoclub.com

 

[Doug Schmidt]

At what point in the start cycle does the hatch unlock?
Key on?
Engine start?
After engine start?

I would also suggest that you go to nico club and download the Factory Service Manual. It may help give some insight on the issue.
www.nicoclub.com

The unlock occurs just after engine start (maybe 1-2 seconds).

Thanks for the tip about the FSM. The "BL" section (Body, Lock, & Security) has a troubleshooting workflow for the back door lock assembly and opener switch.

Unfortunately for me, it looks like I will need to remove the entire back door trim in order to properly troubleshoot these two components. I suspect that's where 95% of the time will go.

I don't have much history of removing body trim (at least in a way that they can be put back on again). I guess its time for me to search YouTube for some tips!

 

[Keith Wagner]

Highly reccommend you find one at a pick and pull to practice on, or to have a spare. That trim panel does easily break.

There are 2 places that send a direct signal to open the hatch.
1 is the Keyless/BCM. Even though you don't have that option on your fob, everything is there for it, and active (and will work with a 4 button fob!).
2 is the swich on the hatch.

 

[Ecate]

(and will work with a 4 button fob!).

it will and it does

 

[Doug Schmidt]

Hmm. The problem (rear hatch unlock on engine start) has stopped this weekend, after I reprogrammed a keyfob (following this help post's sequence).

Once the keyfob was reprogrammed, the rear hatch stopped releasing by itself when the engine was started.

I'll take the win for now, since I don't need to rip apart the rear trim, plus my partner thinks I'm a genius (she's wrong, but I'll let her figure that out on her own).

If the problem resurfaces and another keyfob programming sequence doesn't help, then I'll return to this thread and resume troubleshooting.

Thanks for the helpful hints along the way!