Park Button is Intermittently Working




I’m sure one of you guys has run into this issue as I seem to recall hearing of somebody else with same issue.
About 1/2 the time now I can only get the car (2015 W212 AMG) to go into P if I open the door. The P button just goes dead in these instances no matter how many times I press it or how hard.
Guessing it’s the shift module? Or something else? Hoping it’s a fairly straightforward DIY?
Any confirmation on what causes this or any part number(s) necessary would be very appreciated!
Thanks in Advance
Mine was done under warranty. The dealer replaced the entire shift assembly. Unfortunately, the shifter assembly is all one part (including the electronic module that usually fails), and cannot be purchased separately. I seem to recall dealer cost was north of $900 to replace. It looks to be a pretty easy DIY.
I believe the part itself can be had for ~ $650-$700 online.
Link to the part number the dealer replaced on my car.
https://www.mercedesbenzstarparts.com/oem-parts/mercedes-benz-gear-shift-assembly-2122670100
found this old thread on the issue as well:
https://mbworld.org/forums/w212-amg/717916-2010-e63-park-button-problem-fix.html
Last edited by Ak1mking; Jun 4, 2023 at 01:33 AM.




Mine was done under warranty. The dealer replaced the entire shift assembly. Unfortunately, the shifter assembly is all one part (including the electronic module that usually fails), and cannot be purchased separately. I seem to recall dealer cost was north of $900 to replace. It looks to be a pretty easy DIY.
I believe the part itself can be had for ~ $650-$700 online.
Link to the part number the dealer replaced on my car.
https://www.mercedesbenzstarparts.co...bly-2122670100
found this old thread on the issue as well:
https://mbworld.org/forums/w212-amg/...oblem-fix.html
Interesting I am at around 53k miles now. I also found that link you provided at the end of your post after I posted this thread.
I found the shift mechanism at AutoHauzaz for about $640. The video in your link is pretty clear too. I can manage this DIY totally.
i know you had yours done under warranty, I am going to look for another yourube of pulling the knob off the old mechanism. In that writeup, the guy kinda did it a bit weird. Maybe it’s the best way, but want to see alternative methods.
Thanks Again!
If I wasn’t under warranty, would have done it myself as well. I seem to recall the dealer booked an hour or less of labor for the job.
Good luck - agree with you on the shift knob removal.





I use electronics spray and clean the switch every so often. '13 wagon with 66k. Ive destroyed this switch over and over with coffee and spray or alcohol always fixes it. Remember to let anything dry before energizing.
Just had the shifter trim off today and gave it a little cleaning. One torx screw and some careful trim removal (meaning proper tools) is all it takes. Always worth your twenty minutes to try.. the lazy way is to flood it from above but thats a little bit more sketchy as you have to ensure the chemical will not leave a residue AND is safe for plastic, like a real electronics cleaner.





I use electronics spray and clean the switch every so often. '13 wagon with 66k. Ive destroyed this switch over and over with coffee and spray or alcohol always fixes it. Remember to let anything dry before energizing.
Just had the shifter trim off today and gave it a little cleaning. One torx screw and some careful trim removal (meaning proper tools) is all it takes. Always worth your twenty minutes to try.. the lazy way is to flood it from above but thats a little bit more sketchy as you have to ensure the chemical will not leave a residue AND is safe for plastic, like a real electronics cleaner.




I took apart everything using the same method as shown in the video link above. No issues. Nothing cracked nor broke.
The switch area looked pristine with no signs of any spills. But I sprayed it well around the edges of the switch, let it soak for a few minutes, then blew it dry with the air nozzle. I repeated this process about 4 times. Seemed like it worked at first after re-assembly in my driveway. Drove around the block, went to park in driveway, and not working again. Ugh.
So I just ordered a new shift module from Autohauzaz. $673 shipped.
At least now I know how easy this swap will be when I get the new module.
Also got to perform a nice deep clean of that entire console area. Looks brand new now. Just doesn’t work. Hahaha
I’ll update again after I install the new module. Likely next weekend.
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good to hear you tried and reported the results.
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Are you suggesting I unscrew the 4 Torx bolts and then I can get deeper to the board/electrics better? If that is the case, J will try again today.
Please let me know as soon as you can.
If that works, hopefully I can cancel my Autohauz order or at least send it back in its unopened packaging since I believe there are no returns on opened electronics.
Thanks for the tips!




As mentioned above, there was no signs of spillage or anything near the switch or entire shift module. It was virgin looking.




Hi again, Ive never had to go too far into it. Remove the 3x3 piece and then try and get under the actual button, I believe the black P is over/attached to a white button. I was thinking if you can ensure youre spraying under the button, thats the best shot to clean it. Think about a rubber remote switch and how there is a contact between the button (under the button we touch) and the board. That area is what needs to be cleaned. Though there was no spillage, it could just be some very light corrosion (from perhaps humidity etc) stopping the contact. If this does not work, one can assume that the contact is worn out, not completing the circuit. For how quick it is, its worth a try.
nothing to do with cleaning cause it looks clean.




Without looking into a switch wiring diagram which im not sure is available, I wonder if its a two part switch where both areas must be depressed. Easy enough to try by putting it together and seeing if just hitting the red button with your finger puts it in park.Great job and thanks for this. Like I said, ive avoided an issue (only failed one time a few years ago before the first cleaning) so far and have not had to dive so deep. Thanks for the pics.




I will then tinker with a failure analysis where Robert pointed out to be able to report my visible findings and/or recommendations to repair it for others. I will keep the old module and use it if needed down the road if the new module acts up.
Just one more extra part for my W212 boneyard! Lol
Robert, are you the same Robert I met in Burlingame for EDOK TCU? Power lifter?
Just curious.
Cheers to All on this thread. Thanks guys.
I will then tinker with a failure analysis where Robert pointed out to be able to report my visible findings and/or recommendations to repair it for others. I will keep the old module and use it if needed down the road if the new module acts up.
Just one more extra part for my W212 boneyard! Lol
Robert, are you the same Robert I met in Burlingame for EDOK TCU? Power lifter?
Just curious.
Cheers to All on this thread. Thanks guys.




Hardest part of the install was pulling off the shift knob. I did it in the car after all trim was removed just in case. FWIW I am a longtime gym rat and still benching 315 for 6 reps legit. And it took both hands on mine with near top effort. Maybe mine was tighter than the guy in the link above that did it with one hand or he benches 315 for 10 reps!! 😂
putting it back on the new one took some pressure but only about a 1/4 of the force to pull it off.
I spent only about 20 minutes dissecting the old one for a failure analysis. I can say with certainty that my shift module failure had nothing to do with any spillage.
Robert is correct that there are 2 switches that the P button must activate. The main one that also provides illumination for the red “P” and a secondary red switch that is on the right of the button. In looking at it, it appears the red switch might be the issue. I will do a deeper dive with an ohm meter in the next few days to confirm. There might indeed be a way to save these modules without buying a new $650 module.
FYI, for those that don’t know me, I am a very seasoned Product Design Engineer. So whatever I find will have some confidence behind it. Even if that means I find replacing the module is the best solution.
Will update later.
Cheers




I took mine apart today, cleaned all contacts, applied a pad to the switch underside, reassembled and found no change…still would not move transmission to Park.




Top side of switch ccb
Solder joints under red switch
Underside of switch ccb




loose pins...
two rows of bad pins... done!
> TRIVIAL REPAIR PROCEDURE:
- solder poor connections
- reconnect main/aux batt. power
- scan chassis for colareral errors
- post faults descriptions.
> Tools:
soldering iron + scanner + 5mn patience!
Repeat with next module you want to make reliable.
Suggested are the 4x door modules aka DCU's.
enjoy your rewards !

+++ To fix powertrain ECU/TCU latencies:
You'll need to solder CAN-C VIP'S when you're ready.
Last edited by CaliBenzDriver; Nov 3, 2024 at 02:00 PM.




I say this b/c the overall module is still functioning to select all other gears, all leds, and even park when door opened…seems specifically related to the physical action/mechanical/electrical interaction of the “P” button press. Alas, I HOPE to be wrong!




I will sincerely hope it continues working, but it was completely nonfunctional all last night and this morning. Just functioned 3x after reinstall
@CaliBenzDriver sincere thanks




Suggested are the 4x door modules aka DCU's.
+++ To fix powertrain timings:
You'll need to deal with CAN-C VIP'S when you're ready
How do I access DCUs? 😅




I will sincerely hope it continues working, but it was completely nonfunctional all last night and this morning. Just functioned 3x after reinstall
@CaliBenzDriver sincere thanks
Now you've seen what cancelling marginals connections can do.
ANYWHERE A SIGNIFICANT CURRENT IS INVOLVED it speeds up oxidation of artificially undersized connections.

> INTERCONNECTS PINS :
Power: Vcc; GND;
Data: CAN+; CAN-
Misc: sensor /actuators: I/O's (Input/Output)

Last edited by CaliBenzDriver; Nov 3, 2024 at 03:24 PM.




