Mercedes W638 V230 Petrol Limp Mode

[Daleapowell]

Hi all, I have a Mercedes W638 Petrol V230 which is constantly in limp mode. I have tried to read the diagnostics, however I have been unable to do so as it is a 38pin connector which doesn't show up any results. It starts up, drives and runs well, no warning lights show up on the dash at all. Can anyone help?? I have looked at the vacuum hoses and the first two appear to be fine, however I can't check the other two as I cannot see where they run to in the back of the bulkhead.

I have tried changing the brake switch, but this hasn't changed anything. Can anyone help or at least point me in a general direction to check? The fact that it immediately starts in limo mode makes me think its likely an electrical issue.

Thanks

 

[pete_on_the_go]

Hi. I have the same motor as you. I'm trying to trace the two vacuum hoses you are (the two on the right if you are looking at the vehicle head on) the one on the far right I couldn't blow through soon presuming that's my problem. Yours could be the plug on top of the gear box? I took mine off and gave it a clean with contact cleaner. It seemed to work a lot better. Be careful not to brake any pins on the plug. P.s The collar on the plug spins so make sure it's in the right position before you try put it back. It was mare for me untill I found this out. It can be stiff also. Also check the wires on the base of the plug for brakes.

 

[pete_on_the_go]

On the driver's side air vent inside the cab you can pull it off and there should be a vacuum line behind there. Make sure it's connected

 

[cubiksquared]

Hi all , @pete_on_the_go , do you have the position this collar on the plug should be in ? Mine just spins around freely ?

@Daleapowell mine is in limp mode after it hits 30mph