Berlingo speedo and odometer problem

[Oldschool]

I’ve a 2008 m59 (older model) 1.4 petrol berlingo. Intermittently the speedo and odometer fails, this is associated with a slight change in engine performance and sometimes a beep and handbrake icon on dash when stationary and handbrake applied.I have tried to trace wires from speedo sensor. No 1 appears  as 12 v supply(yellow), no2 seems to be an earth and the third appears to go to the rear connection plug of the engine ecu .I’ve checked the positive supply which seems good, I’ve disconnected and cleaned the plug to the speed sensor with electrical connector spray, I believe that the dash binnacle is ok and the rear electrical connection has been checked and is good, any help appreciated.

[Gryffindor]

This sounds a bit like my problem, except the speedo/milo failure is permanent, I don't get handbrake warnings or change in engine performance, and I get three beeps not one.

See the thread called final drive sensor.

[Oldschool]

Thanks for reply, yeah I also get few beeps not just one, The final drive sensor as far as I know is the speedo sensor which is at the back of the gearbox passengers side, held in place by 1 small Allen key head bolt, . My one works and the fault is intermittent, and whilst it could be this sensor I’m not convinced, i may replace it as an attempt at solving the problem but was hoping someone else had a similar experience and could enlighten me??

[oilyrag]

When I took the sensor out of my similar ZX I was surprised that the circuit board sits in oil - can't see that there'd be too much that could go wrong with it and would focus on connector/wiring first. Good luck!

[Oldschool]

Thank you, yes I checked the positive supply yesterday which was 12 v , and I am now going to check the no 2 earth connection with my multimeter, the third wire no 3 is the signal wire, but I think you’re probably correct that it’s a wiring problem, anyone got a pdf of the wiring for my berlingo by chance? 1.4 petrol 2008, m59 model.

[Sol]

If you can connect a 12v LED (not a lamp) and knowing the polarity is correct for the LED beforehand, between signal and gnd, then as you drive, the LED should pulse - getting quicker as you speed up. If the pulses stop when the speedo stops working, then the wire from the sensor or the sensor itself, has an intermittent fault. You can have it at the sensor end if you can get it connected there and if it fails at that end, the sensor is bad, at the top end, the wiring.

Could test it with the front end up on axle stands while running in gear. I am sure a stream of pulses would be the output on the signal wire, between that and earth.

[Oldschool]

That makes sense, and seems a good way of determining whether problem is the sensor or the wiring post sensor, the next dry weekend I get a chance I will try it.. thank you for your time taken to reply, regards.