Dear Forum, I am new here and
I am doing this thread for my friend who is a Mercedes Lover. He drives a Mercedes E300tdiesel: WDB1241911F288398. It is a Station Wagon and a European Model with a 3 Liter Diesel engine.
He complains about issues with his RPM meter. It bounces and comes back to normal operation.
He complains about slight performance issues on low RPM when the failure occurs. The vehicle has AC but this AC is not OEM (Aftermarket).
The dealership already replaced the speed sensor with an original Mercedes Parts. I do not have access to the vehicle but I am assuming that this is a VR Sensor from Bosch like the DG6 types.
So I have some questions about the system!
Where does the Cockpit gets the RPM Signal from?
Is the Signal a 5TTL signal or an Analog Signal?
What could be the failure?
I have a scope and could record the RPM Signal behind the Cockpit. What pins do I have to wire out?
Sorry guys. Questions over Questions. Maybe you can help.
Does this type of vehicles read the speed signal in the BCM & OR ECM or does the Diesel pump has his own control module.

Thank You
BR
Bob

Is this the correct Schematic for the tachometer rpm signal?

Pin 2 of the X11/11 Test conector should provide us the sensor signal?

Where is the test connector located?
Engine compartment or under the dash board?

Where do I find the ground pad for the EDS (called inside conector N39)???

Thank you
bob

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Hi
according to ETM, N39 is 'right side of component compartment, behind battery'
X11/11 is 'right side of component compartment, left of battery'

cheers

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cheers!!

thank you Balge,

I apresciated your help.

Balge do you have block diagramm for the X11 test connector?

I would like to measure the digital signal of the speed sensor which sould be pin 2 and the pin 1 ground.

And the raw signal inductive before it goes into EDS.
Also pin 1 X11 and pin 20 of the EDS.

Lets see how it works.