Speedo cuts out intermittently - is sensor or wiring more likely

[cwathen]

My speedo keeps cutting out whilst driving, usually only for a few seconds then recovers, all other gauges continue to work. I had been putting up with it but lately it's been happening more and more frequently.

I guess a problem with the sensor, but based on experience is it more likely to be the sensor failing or the wiring to it? Not had a Saxo before but I've got through a few electrical gremlins on it which were all linked to dodgy earths.

Also, whilst the speedo is not functioning, the throttle feels odd - the engine starts to feel like it's slightly lost power, and if coming off and on the gas it jolts, once the speedo comes back it recovers. Is this normal just for the speedo cutting out?!?!

[MartinObviously]

Originally Posted by cwathen

My speedo keeps cutting out whilst driving, usually only for a few seconds then recovers, all other gauges continue to work. I had been putting up with it but lately it's been happening more and more frequently.

I guess a problem with the sensor, but based on experience is it more likely to be the sensor failing or the wiring to it? Not had a Saxo before but I've got through a few electrical gremlins on it which were all linked to dodgy earths.

Also, whilst the speedo is not functioning, the throttle feels odd - the engine starts to feel like it's slightly lost power, and if coming off and on the gas it jolts, once the speedo comes back it recovers. Is this normal just for the speedo cutting out?!?!

The ECU takes in road speed from the sensor. So that would account for you noticing a change in the way the throttle responds.

So you've either a faulty sensor or faulty wiring. It's likely to be the sensor.

other potential could be a wiring issue, but I'd try the sensor first. they've not expensive and easy to replace. just be very careful when levering the old one off, the plastic inside is brittle.

[dutkan]

I have the same problem. Speed was dropping intermittently, but now the speed dial is almost always on zero. And while the speed dial does not work, odometer also doesn't count the mileage. I've also noticed a subtle change in throttle when dial falls to zero. I suppose that all the models have the same principle for speed recognition and kilometers counting (mine is 1998 Citroen Saxo 1.4i SX 55 kW). So I could start from speed sensor, right?

I don't know is this related, but when I press the throttle pedal fully and accelerate few times like that, 2-3 minutes after, all the lamps on dashboard turns on when I change the speed and the car shuts down. I've put it in speed and turned it back on with the remaining inertion (it took 4-5 seconds car to turn on like this). When I did not accelerate this aggressively, car did not turn off during driving, but I've noticed drop in RPM when in neutral (were falling to 600-700 RPM). Is this also related to this speed dial problem.

[VeiRoN]

Got same problem with the Speedo, bought a cheap eaby gearbox speed sensor but still does it, can't find a genuine one.