Keyless Push Button Start Problem
Thread Starter
Junior Member
Joined: Jul 2025
Posts: 41
Likes: 9
From: Connecticut
E350 Sedan, SLK320, XFire Roadster
Keyless Push Button Start Problem
My 2016 E350 keyless start button occasionally doesn't work which requires removing it and inserting the key to start the engine. After starting with the key and then reinstalling the keyless button it operates normally. It appears the keyless button's function is to transfer or transmit the code from the key to the ignition module. What is the fix for this random problem?
Out Of Control!!
Joined: Apr 2019
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From: Silicon Valley
W212 MY'14 M276-3.5NA @75kMi
UNSTABLE KEYLESS FUNCTIONS
My 2016 E350 keyless start button occasionally doesn't work which requires removing it and inserting the key to start the engine.
After starting with the key and then reinstalling the keyless button it operates normally. It appears the keyless button's function is to transfer or transmit the code from the key to the ignition module.
What is the fix for this random problem?
After starting with the key and then reinstalling the keyless button it operates normally. It appears the keyless button's function is to transfer or transmit the code from the key to the ignition module.
What is the fix for this random problem?
- (keyfob...3V coin cell)
- KeylessGo module!
- Electronic Ignition Switch module
Start by scanning all modules to see if any rogue modules are disrupting networking functions.
Understand that modules related to the KEY are always powered ON and temporarily benefit from a simple power restart.
Using the OBSII scanner you can sort out Keyless vs. EIS issue.
Last edited by CaliBenzDriver; Dec 28, 2025 at 12:50 AM.
Thread Starter
Junior Member
Joined: Jul 2025
Posts: 41
Likes: 9
From: Connecticut
E350 Sedan, SLK320, XFire Roadster
Thanks for the multiple check list. I just installed new batteries per message on display. You indicate the state of the key modules as always being ON. Does this mean the button and the key output a momentary pulse to initiate start?
I am not a mechanic tech and don't own a scanner but plan to get one. Can you recommend a good inexpensive OBD2 scanner compatible with Benz and capable of detecting functional states at least at the module level?
I am not a mechanic tech and don't own a scanner but plan to get one. Can you recommend a good inexpensive OBD2 scanner compatible with Benz and capable of detecting functional states at least at the module level?
Out Of Control!!
Joined: Apr 2019
Posts: 11,923
Likes: 6,776
From: Silicon Valley
W212 MY'14 M276-3.5NA @75kMi
Easy Ownership Shortcuts
Thanks for the multiple check list. I just installed new batteries per message on display. You indicate the state of the key modules as always being ON. Does this mean the button and the key output a momentary pulse to initiate start?
I am not a mechanic tech and don't own a scanner but plan to get one. Can you recommend a good inexpensive OBD2 scanner compatible with Benz and capable of detecting functional states at least at the module level?
I am not a mechanic tech and don't own a scanner but plan to get one. Can you recommend a good inexpensive OBD2 scanner compatible with Benz and capable of detecting functional states at least at the module level?
There are newer promissing Bluetooth units becoming more popular with satisfying coverage.
Tied to all this man-made mess is "battery drain by parking"... buy a CTEK or NOCO battery tender to preserve your batteries from knowingly unstable chassis modules.
Member
Joined: Nov 2025
Posts: 85
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From: Taiwan
W212 E63 AMG
My car shop dude left my W212 E63 key on top of the car and sent me off, so I thought it was in the car already then I drove it. Guess what.....Key flew, and was able to find it afterwards, but now buttons are malfucntioned, also key no longer can be detected by the car console. What an incident. Now I will have to look for a key repair specialist or shop for a check. Not sure if it is repaireable. Any suggestions are welcomed.
Thread Starter
Junior Member
Joined: Jul 2025
Posts: 41
Likes: 9
From: Connecticut
E350 Sedan, SLK320, XFire Roadster
Thanks for the ref LAUNCH MB Elite cReaderwill be getting one.
My theory relative to battery tending is if you are going to store your car for a while install a battery switch. When you leave turn it off when you return turn it on. Trying to chase mW drains is a pain plus hooking up and disconnecting a tender is also. A switch provides another level of security and safety.
My theory relative to battery tending is if you are going to store your car for a while install a battery switch. When you leave turn it off when you return turn it on. Trying to chase mW drains is a pain plus hooking up and disconnecting a tender is also. A switch provides another level of security and safety.
Out Of Control!!
Joined: Apr 2019
Posts: 11,923
Likes: 6,776
From: Silicon Valley
W212 MY'14 M276-3.5NA @75kMi
battery power switching
Thanks for the ref LAUNCH MB Elite cReaderwill be getting one.
My theory relative to battery tending is if you are going to store your car for a while install a battery switch. When you leave turn it off when you return turn it on. Trying to chase mW drains is a pain plus hooking up and disconnecting a tender is also. A switch provides another level of security and safety.
My theory relative to battery tending is if you are going to store your car for a while install a battery switch. When you leave turn it off when you return turn it on. Trying to chase mW drains is a pain plus hooking up and disconnecting a tender is also. A switch provides another level of security and safety.
I've considered using battery disconnects when I was dealing with "drain by parking".
A battery switch is not simple with the stock dual battery setup.
Switch may NOT be installed on (-) side because of the smart battery LIN module senses the battery internal heat on the post. Module can not be remote.
The battery (+) side host the pyro fuse on facelift vehicles that used to be inside the Prefuse unit. I
was not able to find switches available to match the positive post size so I simply disconnect the batt (-) at the jump nut.
