Electronic Rear Axle Differential Lock Inoperative

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Mar 27, 2026 | 04:00 AM
  #1  
Hi all,
Hoping to see if anyone in this group could help me.

I have a 2016 AMG GTS that having reoccuring issues with the 'Electronic Rear Axle Differential Lock Inoperative' error.

Parks Place Mercedes in Dallas has seen the vehicle twice : once to repair the Dual Clutch Control Module, and the second time to update the software (not too sure on if they updated the ECU or the recently replaced Dual Clutch control module. Both times, the issue went away for a few days but then would come back.

The car shifts into neutral when driving and the error would pop up. After a bit of time, when at a stop and brakes are applied, the car would lurch forward repeatedly (like it's trying to shift) and the error 'Malfunction' will appear. Restarting the car removes the error for a bit until it inevitably comes back. Also, my odd numbered gears are not able to be shifted into, and manual mode does not activate at all, even though the infotainment display shows manual mode being turned on - the dashboard screen does not show manual mode turning on. The car will only shift into even number gears and the shift hangs considerably. It's like the dual clutch is not wanting to engage the clutch that holds the odd numbered gears for some reason. As mentioned, the issue resolves itself if I turn off the car and turn it back on. Lately, the CEL also turns on.

The car is a bit sketchy to drive. I have relayed all of this to the dealership and I'm not sure they even know what the issue is. I have an appointment to send it back for the 3rd time later next week.

Has anyone encountered this and resolved this

? I have done extensive research online and it looks like a software update fixes the issue, but it's looking like that's not the case for me? Unless the dealer only updated the software for the Dual Clutch controller module and not the car itself?

Thank you for your help!
Reply 0
Mar 27, 2026 | 09:51 AM
  #2  
Sounds like a bad Valve Body/Solenoid in the DCT needs to be replaced to me. When one malfunctions we generally lose either the even or odd gear sets.
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Mar 27, 2026 | 12:43 PM
  #3  
Also, the rear diff malfunction is a known issue for the early model years such as the 2016. The actuator can fail and there's also a software update. With the GT, the transmission and diff are a single unit, so if one is on the fritz, the other can have an issue as well.

You may also wanna read this post. There's a recall for some of the 2016 GTS for an improperly installed retainer clip. That whole thread is a discussion about transmission issues.

https://mbworld.org/forums/coupe-roa...ml#post9267554
Reply 1
Mar 28, 2026 | 07:00 AM
  #4  
You have the Check engine lite in as well. Could your diff message be a biproduct from the engine lite issue?
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Mar 29, 2026 | 03:51 AM
  #5  
Its possessed.
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Yesterday | 04:22 AM
  #6  
Dropped off the car at the dealer today - I didn't receive a Work Order after I picked it up last time, and the dealer told me that they updated the software. Turns out, after reading the service record, the tech only flushed the DCT fluid after getting the car back the second time, and no mention of updating the software.
Hoping dealership correctly fixes it this time around.

Really do think it's a software issue since the car works fine after turning it off and on, and also when the car is warming up and oil/transmission temps are still low.
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