Hello there,

My engine (1.4TDi Fabia 1 2007) won’t start and the OBD says no crankshaft sensor signal.

Troubleshooting shows at the disconnected plug:-

Earth is good

Sensor has good ohms

Signal and power both have 2.5V…!!!

but 2.9V when cranking.

No continuity between power and signal.

Any ideas, is the ECU toast ? Thanks for all help.

What is your engine code?

If it is BNM or BNV then the circuit info looks like this, with no clear marking of +5V or signal, or even +, so I'm not sure you should expect to find a 'power' pin.

Later diagram for BMS engine code (first found in mk2 Fabia I think) shows something more like what you seem to be expecting, or even what you are looking at in terms of a circuit diagram:

Looks to be two different technologies of crank sensor in these two examples.

Edited 25 December, 202525 Dec by Breezy_Pete

Thank you very much for that. My engine code is BNM so I must be looking at the top option which is new to me...!!!

I haven't been able to get my hands on a wiring diagramme but reckon I need to learn how to test the circuit again now....

Looks like the sensor itself may not be a problem as no more error codes after the memory being cleared. Probably something else...uh oh.