2015 W166 EPB will not release
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Senior Member
Joined: Mar 2009
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2019 AMG GT
2015 W166 EPB will not release
2015 ML350 with 2000 miles. Wife parked the car in our garage and went on do other things. Came back to leave and the EPB will not release. I can hear the servos go on and off but the car EPB remains engaged. I went into the Service Menu "Phone on and OK" simultaneous and went to the Brake Pad option and its says "System not OK" and it is stuck there.
Checked the web from my house to Al Gore's Server farm and nothing... I did find a video that shows a manual operation to release the EPB on an S class located in the fuel door, so clearly this has happened on other Models.
Any help is appreciated before it gets towed to the dealer.
Checked the web from my house to Al Gore's Server farm and nothing... I did find a video that shows a manual operation to release the EPB on an S class located in the fuel door, so clearly this has happened on other Models.
Any help is appreciated before it gets towed to the dealer.
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From: The Great White North
W204 C63 Coupe, W166 ML350 BlueTEC, 928GT, Taycan GTS Sport Turismo, C5 Z06 & IS300 race cars
The only other thing to try if you haven't already is to put the car in D (or R depending on which way the car is facing obviously) with the parking brake still on and step on the gas. The electronic parking brake automatically releases when the vehicle is in D or R and you step on the accelerator, which puts just a tiny bit of a jerk on the drive train in case the reason why the brake won't release is because the brake shoes are binding to the hubs (i.e. they have rusted on) if she washed she car, drove through a puddle of water or through slush / snow before parking it. It occasionally happens on mine.
If that doesn't help and you can hear the motor attempting to release the brake but can't, AFAIK your only choice is to have it towed.
If that doesn't help and you can hear the motor attempting to release the brake but can't, AFAIK your only choice is to have it towed.
Thread Starter
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2019 AMG GT
Contacted two separate dealers' service managers and they are stumped. At their recommendation I disconnected the battery for a few hours... no change.
They then said to exit the car, close the door and cycle Arm/Disarm 3 times to reset s/w.... nada.
They said they would send a dealer technician out to reset it with their computer - Excellent... Wow MB stepped it up. 2 Hours later they cancelled because its a safety issue.
Its off to the dealer tomorrow... sigh!!!
They then said to exit the car, close the door and cycle Arm/Disarm 3 times to reset s/w.... nada.
They said they would send a dealer technician out to reset it with their computer - Excellent... Wow MB stepped it up. 2 Hours later they cancelled because its a safety issue.
Its off to the dealer tomorrow... sigh!!!
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Joined: Jan 2013
Posts: 3,745
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From: The Great White North
W204 C63 Coupe, W166 ML350 BlueTEC, 928GT, Taycan GTS Sport Turismo, C5 Z06 & IS300 race cars
Sorry to hear - it's a real PITA when you have to get it towed in. 
Sounds like a "hardware" problem (mechanical or a failed sensor - not something that a system reset would fix) if you can hear the servo working but the parking brake won't release. Curious what they find - let us know once you get it back.
Sounds like a "hardware" problem (mechanical or a failed sensor - not something that a system reset would fix) if you can hear the servo working but the parking brake won't release. Curious what they find - let us know once you get it back.
Thread Starter
Senior Member
Joined: Mar 2009
Posts: 272
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2019 AMG GT
Sorry to hear - it's a real PITA when you have to get it towed in. Sounds like a "hardware" problem (mechanical or a failed sensor - not something that a system reset would fix) if you can hear the servo working but the parking brake won't release. Curious what they find - let us know once you get it back.
Sounds like a "hardware" problem (mechanical or a failed sensor - not something that a system reset would fix) if you can hear the servo working but the parking brake won't release. Curious what they find - let us know once you get it back.Trending Topics
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From: Maricopa, AZ
2012 S63, 2013 E350 Bluetec
I had something like this happen, but not exactly. What happened with mine is I'm driving down the freeway and smell brakes. I'm thinking it's a semi in front of me somewhere and don't think anything about it, except that it got worse. I look in the driver side mirror and smoke is coming from the back tires/wheel. I pull off the freeway, end up having it towed to the dealership. Turns out the electronic parking brake just got applied to that one wheel. Dealership had to order the EBM from Germany (why they don't stock them I have no idea). Took awhile, but they ended up replacing rotors, pads and tires on all four wheels. (I had tire and wheel protection and it really did a number on the one tire, so they replaced all of them as a courtesy.)
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