14cux - road speed transducer issue

[wheelbarrowman]

I have a 14cux that was working nicely.

It has recently started stalling approaching junctions,.so I thought something must be up with the speed transducer.

I can verify by rolling the vehicle backwards/ forwards I can measure the output of the transducer a voltage varying 0-12v which I understand to be correct..I.e. the input to the ECU is 0-12v as the car moves.

If I watch rover guage (everything re connected) I do not see any reported road speed. When driving slowly I can occasionally get 1-3 mph registering, but at and speed it records 0mph.

All other sensors read sensible values.

[wheelbarrowman]

Observing rover guage, it seems that the idle mode is not changed when the vehicle is moving.

I wonder if internal ECU fault.

[Daryl357]

Which transducer have you measured, the gearbox or diff ?

[wheelbarrowman]

Mine is inline with/driven by a speedometer cable. It is a land rover part used on the discovery with 14cux.

[Daryl357]

Ah, I'm not familiar with that type but I assume it still goes to pin 6 on the ecu ? if you aren't measuring from there then you could check the continuity from there to the speed transducer.

[wheelbarrowman]

Yes, its the pin six input.

I measured continuity from the transudcer to pin 6 on the ECU connector, all good.

I had wondered if grounding was an issue, i cleanded and checked the grounds / resistance between ground points on the vehicle. They all seem good.

I'm going to try another ECU.

I was wondering if there's a known normal measurement value for the pin 6 input e.g. resistance to ground that I could use to very if the ECU is good.

[Daryl357]

Just measured mine and pin 6 to ground is 11.79k ohms.