W210 K40 Relay blowing fuse

[bob6600]

Can you post up your vin number please or PM if you prefer

You can have the VIN if you wish grober but I have finally solved the problem I think!

I disconnected the duo valve, fuse still blows
I disconnected the circulation pump, fuse still blows
M55 disconnected again, fuse still blows

Then after a lot of head scratching I thought I'd check again. I remember that the car was fine for a day and then I had a loss of water. The pipe on the top of the EGR cooler blew off, mainly because the clip was not on the pipe but just on the hose (my fault). So I checked everything around this area again and there is a connector that plugs into the top of the gearbox (or back of the engine). Connector removed, sprayed with contact cleaner, blown with air and reconnected. FUSE DOESN'T BLOW! I managed to connect STAR to it and cleared all faults. i have attached pics below of the connector and the possible fault (which I couldn't read at the time).

Thank you again for all the replies and help, I hope this thread will help someone in the future.

but I have finally solved the problem I think!

I disconnected the duo valve, fuse still blows
I disconnected the circulation pump, fuse still blows
M55 disconnected again, fuse still blows

Then after a lot of head scratching I thought I'd check again. I remember that the car was fine for a day and then I had a loss of water. The pipe on the top of the EGR cooler blew off, mainly because the clip was not on the pipe but just on the hose (my fault). So I checked everything around this area again and there is a connector that plugs into the top of the gearbox (or back of the engine). Connector removed, sprayed with contact cleaner, blown with air and reconnected. FUSE DOESN'T BLOW! I managed to connect STAR to it and cleared all faults. i have attached pics below of the connector and the possible fault (which I couldn't read at the time).

Thank you again for all the replies and help, I hope this thread will help someone in the future.

 

[grober]

Glad you got it sorted. I guessing that what you have there is a type of "CPS " sensor except it doesn't process signals in quite the same way. It senses engine speed not crank position. That's because I'm guessing ?? your diesel injection system may be part mechanical /part electrical. With a part mechanical system the injector timing is controlled directly by a pump mechanical connection to the engine itself- no electronic processing. What is controlled electrically is the position of the pump rack [ the diesel equivalent of a throttle] and that requires an ECU to integrate all the signals from various sensors engine temperature , turbo boost?, transmission? engine speed etc to present a final control signal to the injection pump. PWM stands for pulse width modulation which is a form of signal encoding that the ECU can interpret. I'm guessing that engine speed sensor needed a voltage supply and maybe with the connector off it was shorting to earth or causing an excessive current drain somewhere that caused the fuse to blow. Whatever without that engine speed sensor the car was never going to run. ---no doubt someone will be along shortly to tell me I'm talking mince- but no matter the cars a runner!