2015 E-350 US, Gasoline, 30k miles keyfob buttons work, new battery in keyfobs.

The other day my Keyless go stopped working. It has always worked.

Door Locks: none of the doors open by the handles. There are no message on the cluster during the failed attempts. The keyfob unlocks and locks the doors.

Trunk: The trunk does not open with a foot sweep, the trunk & lock button on the trunk doesn’t work. But the trunk close without lock button on the trunk does work. The Keyfob button opens the trunk.

Ignition: the push button start does not work. There are no “key not detected” warnings. After failed push attempts it say insert key to start. Once the key is inserted it starts right up.

I also realized the ECO mode is not working. It has also worked in the past. I thought I was driving different, but I can’t get the engine to stop no matter how I push the brake at a stop.

I’m not getting any faults or warnings from the car itself. Any ideas? Thank you in advance.

 

Charge your main battery.

 

Check your state of charge with a multimeter before charging to see what kind of condition the battery is in. It should read around 12.6v.

 

^ +1

Main battery

 

Replace key battery. I buy ml350 with low mileage and low battery from ford dealer. Then i found out keyless and go working intermittently. i remember when i buy they persuaded me to buy extended warrantie. Then i realise why they sell below ghe market price. Replacing key battery resolve the problem. Also when i test drive they remove keyless and go to have use
the key. I just surprised that even car dealer didn't even know that the key had battery in it.
I just realised you mention you had new key battery. Make sure you got correct battery because i think at least two kind it fit and one thinner than other. The thin one will cause problem and you need to put something so it contact better. Always buy the thicker one

 

The problem is the main battery in the engine compartment. Charge it fully to Float Condition and the car will come to life.

As for key fob batteries, they are designed to use the CR2025 (thinner) battery. Some people jam the CR2032 in there, but it is the wrong battery technically as CR2025 is specified on page 93 of the manual. If you bought your MB at a Ford dealer, the Manual is available at the Mercedes-Benz website.

 

Revised

 

Looks like you guys are right! Thank you for the help. Now to get a new battery, is it true you can’t just switch out the battery yourself? Or if you do there’s a bunch of stuff you have to do aftward that is lost due to the lack of power?

 

Thanks for sharing your screenshot . I love such details as well
Glad, you found the problem

 

My non-keyless go remote uses the 2025's. 2013 E350 USDM. My Owner's Manual verifies this.

 

The manual I have

 

You are correct, my manual says 2025 also

 

I made a feeble attempt to fix the fob battery fit issue a couple months ago... https://mbworld.org/forums/e-class-w...y-battery.html

Key fob battery charge state and fit play a role in Keyless-Go function. But the non-functioning ECO Stop/Start is caused by the weak MAIN battery. Best to keep both topics separate.

 

OK

 

You know this already, but I posted my comment for the benefit of smokinfish...

 

thank you for the comment. I replaced both the main battery and the accessories battery. The eco mode is back and performing normally. The car even has a little more pep to it. However as you implied the keyless go is still an issue.

The key fobs function when pressing the buttons. I do not get a replace battery warning when in or near the car. Before I could touch any door and get a response. Now, no doors are responding. When I get in and press the start ignition button with my foot on the brake nothing happens. No messages nothing. Eventually it will tell me to remove start button and insert the key. The handfree trunk open and close trunk and lock button is not functioning. The colts trunk button does work.

i have replaced the battery in both key fobs with a 2025 new battery.

 

Do you get a "key not recognized" message in the cluster when you put your hand in the door handle with the fob out of range? Is the car sensing your hand?

 

Nothing appears on the cluster when I touch the door handles, with or without keys.

I connected a ICarsoft MBII reader to it today and got the following fault code for keyless go B226155.

Not sure what it means other than there is a problem.

 

Code = KG module internal malfunction. Do both keys malfunction? Only have 1 key, visually inspect KG CU condition in trunk including connector/pins - unplug in an attempt to reset. If this fails best to have someone pull codes using MB diagnostics inclusive of key if reluctant to do so you can replace CU (plug & play) need VIN to supply correct part #.

 

Now I'm no expert, but I THINK this code may have something to do with your keyless go issue. I would investigate and repair accordingly then go from there.