Trunk lock / REM issue? But no faults!?

[Alpine-F80]

This is a very weird one. My trunk / tailgate wasn't working intermittently, and eventually stopped completely. Scanned for faults in ISTA and found "Fault Code; 804843: Central locking drive tailgate, short circuit".

After checking fuses, valet mode in glovebox, testing voltage, and doing some ISTA diagnostics I replaced the Trunk Lock Actuator. This seemed to help, as I can now trigger the trunk/tailgate open 100% of the time in ISTA via the REM & the short circuit faults are gone in ISTA.

I tried resetting Fault counter in REM a few times in ISTA, disconnected battery for an hour, VO coded the REM & FEM, but still can't unlock trunk with key or button. Both FEM & REM show green in ISTA and they show as operating fine. No other issues from the REM (e.g. windows, taillights, etc.)

I'm so stumped...I'm wondering if the REM (or FEM?) has reached the "Max Fault Limit", and is now locking out the tailgate?

I've checked Tool32 & didn't see any errors but I'm also not super familiar with it and am afraid of screwing things up worse just to fix the trunk! I've only seen tutorials on resetting the fault limit for lights.

Any ideas!? I don't even know if I could take it to the dealer because my car is pretty heavily modified...

[Alpine-F80]

One other thing, in ISTA if I attempt to "Reset Fault Memory" of the FEM I get an error "ECU_CONDITIONS_NOT_CORRECT". Same thing works fine on REM. Restarting FEM & REM seems to work fine.

Again, no other issues with the car, and no friggin' codes!?

[Alpine-F80]

Following up on this in case anyone else runs into this bizarre issue. I had to replace both the trunk lock actuator AND the REM. I believe this is because I reached a 'max fault limit', and when that happens the ECU controlling the part (REM in this case) locks out that circuit.
It's possible someone could have cleared out the short circuit fault counter in Tool32, but I didn't have luck doing that and a used REM was $35 on Ebay.

So glad to have my trunk working again...

[DavidJ]

When you purchased the REM did you do the reprogramming yourself?
I kind of having the similar problem with my 2014 F32 4 series.

But in case my rear view camera and pdc sensors are not working also.
Can you please advise?

[Alpine-F80]

Originally Posted by DavidJ

When you purchased the REM did you do the reprogramming yourself?
I kind of having the similar problem with my 2014 F32 4 series.

But in case my rear view camera and pdc sensors are not working also.
Can you please advise?

Yes, I did code the REM myself, I am definitely not a pro though.

I followed the steps I've seen elsewhere to "VO Code a specific ECU" in E-Sys:

Connect => Read FA (VO) => Activate FA (VO) => Read SVT (VCM) => Left-Click on desired ECU => Click on "Detect CAF for SWE" => Select the CAFD from latest I-Level shown => Select OK => Right-Click on ECU (the ECU itself not the underlying CAFD) => Select CODE.

[DavidJ]

Originally Posted by Alpine-F80

Yes, I did code the REM myself, I am definitely not a pro though.

I followed the steps I've seen elsewhere to "VO Code a specific ECU" in E-Sys:

Connect => Read FA (VO) => Activate FA (VO) => Read SVT (VCM) => Left-Click on desired ECU => Click on "Detect CAF for SWE" => Select the CAFD from latest I-Level shown => Select OK => Right-Click on ECU (the ECU itself not the underlying CAFD) => Select CODE.

Thank you for your reply. But now I have a situation where the trunk does not open anymore and there is no emergency release either. Where can I get the program "E-SYS" to reprogram the REM? Do you or anyone know how I can get the trunk open?

Thank you in advance and much appreciated.

[Alpine-F80]

Originally Posted by DavidJ

Thank you for your reply. But now I have a situation where the trunk does not open anymore and there is no emergency release either. Where can I get the program "E-SYS" to reprogram the REM? Do you or anyone know how I can get the trunk open?

Thank you in advance and much appreciated.

Sorry for not getting back sooner, I hope you've made it into your trunk by now! I had the same issue...

Are you certain there isn't a glow in the dark pull handle on the inside of your trunk? It is NOT easy to access from these cars unfortunately...this thread shows better than I'll be able to explain. In short I removed the side bolster of the left rear seat, wedged something to get a LIIITTLE visibility, then reached in with a pole with hook taped onto end.