SimonJA

I have a 2005 CLK350 convertible and for a while now it mostly won't shift into park or reverse so I have to turn the engine off and restart to reverse. It doesn't do it every time but more often than not.

I also noticed quite early on that I can tell if it's not going to go into reverse because when I stop the parking sensors don't light up or work.

So I'm thinking that there is a speed sensor that activates the parking sensors below a certain speed and this sensor also locks you out of putting the car into reverse or park at speed also.

I can't find any info on a speed sensor for this on line anywhere, I know there are other speed sensors for ABS, etc but I've not got any ABS lights on and everything else works fine so I'm thinking there is another sensor somewhere that just locks out reverse and park and activates the parking sensors.

I would grateful for any help finding this sensor or solving this.

Rudeney

When you say it won't shift, do you mean you physically cannot move the shift lever into reverse or park, or that you can do that and it simply does not actually operate in reverse or park? Also, you say "2005 CLK350" - the CLK350 did not come out until MY2006 (though was likely on sale the latter half of calendar year 2005). If it is a MY2006 CLK350, you have the 722.9 transmission which had some issues with the conductor plate in early (pre-2008) models.

SimonJA

Yes when I say locked out it is physically prevented from going into park or reverse.

Car was first registered in 2005.

Rudeney

There is an interlock which is controlled by the TCU. I'd get codes pulled from the TCU and the EGS (gearshift module) to see what's going on. The conductor plate in these transmissions is notorious for failure, especially in earlier models (prior to 2008).