Keyless Go stop/start button problem - R230

[Paul Grainger]

After the installation of VCS (Linguatronic) to my SL I seem to have inherited a problem with my keyless go. The problem may be as a result of something that I have 'done' whilst installing the VCS equipment but I have checked all of my work and cant find anything that may have caused the problem.

All keyless go functions work OK with the exception of the stop/start button. The door locks all work normally in the 'keyless way'. Whe I'm in the car, however, and press the button on the gear-shift, nothing happens.

This isn't a key problem. I am not getting the 'no key detected' warning if I press the button with no key near the car. All the symptoms are that the car electronics are not registering the pressing of the start button.

Star diagnosis is showing no faults with keyless go, but also is not registering operation of the stop/start button.

Having searched this problem on the internet I concluded that the most likely problem was a broken wire between the button and the ESM shifter module. I stripped the whole lot down and concluded that nothing appears to be wrong. I can get a good reliable (near zero ohms) test when pressing the button, tested at the point where the plug enters the ESM module.

There are two plugs from the shift module to the car main loom. One of these appears to be the tiptronic and shift lock solenoid functions, the second appears to be for the starter button. My multimeter shows open circuit changing to zero ohms on this outgoing socket when I press the starter button.

From this point I have no idea what to do next. Does anyone have a wiring diagram of the keyless go system - I really only need the section relating to the stop start button. I'm guessing that this pair of wires (there's only two of them on the second plug and socket) must go directly to the keyless go module but I don't know this for certain and I don' even know where the module is located! (the car is a 2005 SL55)

I have to face up to the fact that its very possible that I have disturbed this wiring and caused a problem when I installed the VCS system.

Can anyone offer any suggestions??

Paul G

 

[Darnott]

Paul

see the attached.

The Start / Stop switch is wired in to the "Electronics elector lever module control unit (N15/5), from there via the violet/yellow wire to the "KEYLESS-GO control unit (N69/5)" (via connector X99/5).

 

[Lyserman]

I seem to remember reading an article that said there was a wire that broke at the bottom of the gear stick and it was fairly common.
I will try and find it again...

 

[Lyserman]

Here it is:
KEYLESS GO wire broken - MBWorld.org Forums

Tony

 

[Paul Grainger]

Its definitely not the wiring from the gear stick - thats exactly what I was expecting it to be and hence my full strip down of the ESM (electronic selector module, ie the shifter unit). The wiring in there is like new (as also is the plastic shift interlock, I figured that I would change this if there was any sign whatsoever of fatigue or cracking)

However..... a massive thanks to Darnott. I haven't yet had chance to fully make checks but the drawings that you sent show connector X99/5 as a single core plug and socket connector in the EXACT location (cable ducting behind passenger seat) that I was working when I installed the cable loom for the VCS module. I'm certain that this will be the problem - and will sort it out in the next couple of days.

Paul G

 

[richard]

I think theres also a KG antenna just further forward than the selector, make sure you didn't unplug that - I seem to recall its a single wire connection. (Perhaps easier to check than the wiring duct connector)

(edit, wiring shows it as 2 pole connector)

R

 

[Paul Grainger]

Yes I spotted that aerial and it's ok Richard. If I had a problem with the aerials or the key I would get 'key not identified' (or whatever the message is) on the cluster LCD when I press the start button. I'm not getting that message..... not getting anything..... It's like I'm not pressing the button as far as the car is concerned - which points to either a duff button (checked); wire at the base of the gearstick (checked); or a loom or module problem.
It seemed incredibly coincidental that this problem started when I installed the VCS loom and I was hoping for exactly what the drawing shows ..... A push together connector in close proximity to the MOST wake up distributor. This connector is on the single core wire from the button to the keyless go module and an open circuit at this point would exactly explain my symptoms

Paul

 

[richard]

Yes I spotted that aerial and it's ok Richard. If I had a problem with the aerials or the key I would get 'key not identified' (or whatever the message is) on the cluster LCD when I press the start button. I'm not getting that message..... not getting anything..... It's like I'm not pressing the button as far as the car is concerned - which points to either a duff button (checked); wire at the base of the gearstick (checked); or a loom or module problem.
It seemed incredibly coincidental that this problem started when I installed the VCS loom and I was hoping for exactly what the drawing shows ..... A push together connector in close proximity to the MOST wake up distributor. This connector is on the single core wire from the button to the keyless go module and an open circuit at this point would exactly explain my symptoms

Paul

Yes, agreed !

R

 

[Paul Grainger]

All sorted and working normally again! The connector wasn't in great condition so the wires are now soldered and heat-shrinked to make a proper and permanent connection. The button worked immediately after this repair.

Thanks to everyone who took the time to reply to this post

Paul G