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How fresh is your vehicle battery, and auxiliary battery? Strange electrical things happen when batteries are not in good condition. It's also good practice to keep a fresh battery in the fob.
After confirming fresh batteries, there are three modules to be aware of: liftgate control unit N121/1, rear fuse box F4 and rear SAM N10. The liftgate control unit is on the right (passenger) side wall behind the trim panel. I haven't located F4 or N10, but would start in the rear side wall and rear spare tire areas.
Can you read codes, ideally using a Xentry/DAS system? Sounds a little like a bad liftgate control unit, but there is more diagnosing to do.
How fresh is your vehicle battery, and auxiliary battery? Strange electrical things happen when batteries are not in good condition. It's also good practice to keep a fresh battery in the fob.
After confirming fresh batteries, there are three modules to be aware of: liftgate control unit N121/1, rear fuse box F4 and rear SAM N10. The liftgate control unit is on the right (passenger) side wall behind the trim panel. I haven't located F4 or N10, but would start in the rear side wall and rear spare tire areas.
Can you read codes, ideally using a Xentry/DAS system? Sounds a little like a bad liftgate control unit, but there is more diagnosing to do.
Thanks - is the absolutely no way to manually open the trunk?
I found the rear fuse box, it is under the middle row of seats, on left side. I checked every fuse using a voltmeter... they are all 100% fine. I then proceeded to check every fuse on the other two fuse boxes -also fine!
Where is the lift gate control located? It is very had to acces the rear cargo area if the trunk cannot be opened!
I ordered a icarsoft reader. It noted the below error code:
Odd... when the gate is opened manually, the button on trunk, my key, and even the inside door is responsive.... but after closing, it returns to being unresponsive...?
I am having doubts whether this is SAM related. The rear SAM controls tons of stuff. Why then is only the tailgate having issues?
What about this module? Not sure where it is but will search for it next.
When the liftgate is closed, what method is used to open it?
Sounds like a point failure, rather than a system failure. Seems like the latch has a bad switch, or the lift cylinders are getting flaky. Do the lift cylinders function correctly, other than the failure to open when closed situation?
A new liftgate control module is $300, compared with your eBay example of $90. If it were my vehicle, and I was 100% sure the liftgate module was bad, I would order a new one and not take the chance on a used piece of electronic equipment.
If I can jump on this thread, I have been dealing with the same issue. I put in a new small battery in the trunk, the fuses are good, etc. I got an Icarsoft I980 and have the below codes. I cleared them thinking it could just be a fluke. not that lucky.
What "close trunk lid" button do we think that is? The one in the drivers door, or the one in the rear compartment? Hopefully not the one in the trunk its self. if i push and pull on both buttons, the trunk will release but not actually open. I have to open and close it manually. It sounds I am manually moving the motor, gears when I do this.
Would the dealer software give better info?
Also, should the Icarsfot I980 be able to reset the service interval? I cleared the codes and I still have the A9 code showing on the dash. Is there a way to clear codes?
Finally, does anyone know what the Position 1,2,3,etc are on the Icarsoft?
If I can jump on this thread, I have been dealing with the same issue. I put in a new small battery in the trunk, the fuses are good, etc. I got an Icarsoft I980 and have the below codes. I cleared them thinking it could just be a fluke. not that lucky.
What "close trunk lid" button do we think that is? The one in the drivers door, or the one in the rear compartment? Hopefully not the one in the trunk its self. if i push and pull on both buttons, the trunk will release but not actually open. I have to open and close it manually. It sounds I am manually moving the motor, gears when I do this.
Would the dealer software give better info?
Also, should the Icarsfot I980 be able to reset the service interval? I cleared the codes and I still have the A9 code showing on the dash. Is there a way to clear codes?
Finally, does anyone know what the Position 1,2,3,etc are on the Icarsoft?
Thanks for the help.
To find out which button is problematic, do multiple tests of opening/closing to narrow things down.
- key fob
- driver's door button
- button on inside of liftgate
- button outside of liftgate above license plate
The generic suggestion for diagnostic systems is to use Xentry/DAS. Other systems will work, partially.
Thanks for the thought. None of the buttons actually open the trunk, all of them sort of pop the trunk but then it does not move. Which makes me think it could be the motor? I see if any codes come back.
Thanks for the thought. None of the buttons actually open the trunk, all of them sort of pop the trunk but then it does not move. Which makes me think it could be the motor? I see if any codes come back.
Agree seems like the motors. The buttons, latch and electronic modules seem to be functioning OK.
WIS AR72.20-P-7551GQ says nothing about SCN coding after N121/1 replacement. It does specify to "normalize liftgate control unit N121/1". There is no procedure or specification for normalizing.
For other sensors and systems (windows, steering wheel sensors), normalization is a manual (non-coding) procedure whereby limits of travel are established.
WIS AR72.20-P-7551GQ says nothing about SCN coding after N121/1 replacement. It does specify to "normalize liftgate control unit N121/1". There is no procedure or specification for normalizing.
For other sensors and systems (windows, steering wheel sensors), normalization is a manual (non-coding) procedure whereby limits of travel are established.
great news!! Thanks, the module will be here next week. Hopefully save me a trip.
Rear lift gate unlatches but does not open or close
Originally Posted by silvergl
The dealer diagnosed it as a failed lift gate control unit N121/1.
I am going to order a new one, does anyone know if I need to get it programmed to the car or will it plug and play?
Hopefully this fixes it once and for all.
Also, not what the carsoft suggested, interestingly.
Did you get the lift gate control module installed and did it fix the issue? My 2015 GL 350 is doing the same. I purchased a used control module on ebay but my lift gate is still unlatching and nothing else. I checked continuity on the door actuator arm and it was good. I check all of the fuses and they are good. I was wondering if the replaced control module needed to be programmed?
I had to get mine programmed, in hindsight after further research I probably only needed the unit reprogrammed and did not need to replace it. It only took an hour or less, pretty simple and there lots of tutorials.
I had to get mine programmed, in hindsight after further research I probably only needed the unit reprogrammed and did not need to replace it. It only took an hour or less, pretty simple and there lots of tutorials.
HOw did you reprogram it? Would you be able to share a link for tutorial? Thanks.
Silvergl,
I am facing a similar issue. The trunk won't power open or close. I can hear the motor in the strut working when I press any of the buttons. I can also open/close the trunk manually without any problem. Were you able to hear the motor in the right strut working when you pressed any of the buttons (fob, driver, trunk)?
Thank you
LL
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