E-Class Coupe (C238) & Cabrio (A238) 2017 - E200, E220, E300, E350, E400, E450 [Coupes &Cabriolets]

Retrofitting keyless entry

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Old Jul 5, 2025 | 10:06 AM
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Retrofitting keyless entry

I’m trying to retrofit keyless entry to my A238 2020 cabriolet
had a look at the aliexpress ones but wanted to go factory so bought door handles x 2 and internal lock mounting brackets to go with them.

from what i’ve found so far it’s possible to just wire up drivers door that already has antenna fitted so the two wires from drivers door handle need routing to the KG module in right rear of car then code up

can anyone point me in the right direction of wiring diagrams for drivers keyless door locking please.

ill put how to on if i can get this working.
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Old Aug 6, 2025 | 11:12 AM
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just a quick update

I managed to get hold of front passenger/drivers door handles

My car is 2020 cabriolet e class 238 but same handles as coupe and i think saloon w213
you also need the inner back mounts
passenger uk RHD is

drivers side uk RHD

as i only plan to make drivers side keyless entry i’ve only bought wiring for right hand side drivers door (uk)

this wiring connects to keyless handle sensor and led door handle pocket led (this goes into green connector front door ecu and will need coding)
same part number fits passenger and drivers side, not sure if four door cars have same loom but would think it will be.

keyless part of loom missing from my car has three wires brown and white go through door connector (29pin x35)
to KGM module in rear
other violet wire in same connector comes from door control unit, at the moment i can’t find what this wire does as it doesn’t appear on any wiring diagrams i’ve found

green connector = door ecu
white 3pin = goes to kgm module in rear

the connecting loom from lock loom to door connector has two plugs
white extends into door connector for lock/unlock signal but as yet not sure on violet wire

this connector is for drivers door antenna

but KG module in rear has pins for passenger front rear drivers rear antenna but no drivers door so again can’t find where the drivers door antenna connects too
this is KGM pin diagram

So basically it’s two wire from drivers side door handle that connect to KGM in rear then two antennas one in drivers door and one in boot/trunk then coding by someone much smarter than me 🤣
but violet wire has me stumped and where to connect drivers door antenna.
if anyone can help i would be very grateful 🙏


Last edited by mollie; Aug 6, 2025 at 11:33 AM.
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Old Aug 6, 2025 | 01:16 PM
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I am not familiar with 2020 specs but for previous generations, KLG required different keys.
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Old Aug 6, 2025 | 02:25 PM
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from what i’ve read original key can be coded to keyless entry but i’m not sure as no one has posted any retro fit success
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Old Aug 6, 2025 | 09:43 PM
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This place is a joke.
This simply isn't possible
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Old Aug 7, 2025 | 07:10 AM
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Originally Posted by E55Greasemonkey
This simply isn't possible

someone has said using original parts fitted to E class coupe, not aliexpress kit
So i live in hope 🤞


Last edited by mollie; Aug 7, 2025 at 07:12 AM.
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Old Aug 15, 2025 | 05:44 AM
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quick update
both inner door carrier's have to be changed for new keyless outer handles

This is a difficult as the whole locking mechanism has to come apart to fit




the new keyless door looms are plug and play connecting to door handle led’s, lock/unlock sensor, door lock motor, door control module then onto main door car connector


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Old Aug 15, 2025 | 11:02 AM
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Originally Posted by mollie
from what i’ve read original key can be coded to keyless entry but i’m not sure as no one has posted any retro fit success
W238 Key is already Keyless compatible, as all w238 have Keyless Start
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Old Aug 16, 2025 | 02:53 AM
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Originally Posted by trigital
W238 Key is already Keyless compatible, as all w238 have Keyless Start
Thank you for your input
Its very helpful 👍
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Old Aug 16, 2025 | 06:52 AM
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so getting ready to run the body loom up to KGM in boot/ trunk
after looking at mine it’s not got enough pins for keyless

found what i believe to be the correct one for my car but it’s not new

so not sure if used KGM can be coded or do i have to buy new ?
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Old Aug 16, 2025 | 06:59 AM
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No worries, it can be coded if is Second hand. The Keyless module doesn't handle any security, just forward the signals from each side antenna and capacitive sensor.

4 wires from each door to module
And besides handles, antennas, support for handles you have to be sure that the magnetic part - from the fixed part of the handle - should be installed as well
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Old Aug 16, 2025 | 07:17 AM
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Thank you that’s great
can i ask what you mean by magnetic part of the fixed handle
I’ve used genuine mercedes handles and back inner door mounts

Last edited by mollie; Aug 16, 2025 at 07:30 AM.
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Old Aug 16, 2025 | 10:11 AM
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On left door is included in Part numbered 190
On right door the Part 200 it's mandatory


Last edited by trigital; Aug 16, 2025 at 10:42 AM.
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Old Aug 16, 2025 | 12:34 PM
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Yes i have this 👍👍👍
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Old Aug 16, 2025 | 12:43 PM
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Originally Posted by mollie
Yes i have this 👍👍👍
With Keyless option as the old one looks alike but not working
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Old Aug 16, 2025 | 01:30 PM
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ok i’ll check the part number A0997602500



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Old Aug 17, 2025 | 03:40 AM
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Originally Posted by trigital
With Keyless option as the old one looks alike but not working
you are spot on mine is different to the keyless Version
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Old Aug 17, 2025 | 03:45 AM
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m

mine is flat
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Old Aug 23, 2025 | 11:38 AM
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Today more parts arrived so made up my keyless go loom


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Old Aug 23, 2025 | 11:55 AM
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Old Aug 23, 2025 | 12:58 PM
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Not sure if i’m overthinking this but the kgm has a Q number

wondering if the antennas have to mach as i’ve seen Q1 Q2 Q3

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Old Aug 24, 2025 | 02:34 PM
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so now even more unsure my original KGM has Q1 that doesn’t support keyless entry the new one that does has Q2
My front centre console antenna already fitted has Q1 but boot/trunk has Q3
They all have same part number A2059053005 but is Q part relevant ?
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Old Aug 30, 2025 | 08:25 AM
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Done a bit more of the wiring today, had a look at the centre console antenna.
Different part number and connector to doors/ rear.

So decided to get all the wiring in drivers door connected and run the loom to KGM

Before

After (Antenna wiring)



Before

After (lock signal)


Door connector



Last edited by mollie; Aug 30, 2025 at 08:27 AM.
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Old Sep 6, 2025 | 09:07 AM
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So today i finished off the install, all wired up and tested, did a quick obd scan, just showed one fault within KG module, thinking this could be because it’s not coded to my car 🤞


And as i’ve had half the car apart, interior was very messy so given her an Ocd clean 🤣



Last edited by mollie; Sep 6, 2025 at 09:20 AM.
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Old Sep 6, 2025 | 12:19 PM
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A2229004618 is the exchanged module or the original one?
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