Speed Sensor - I think....

[C.A.R.]

Loving my HDi at the moment - giving me low-cost hyper miles with little to no maintenance in between. I think that's the reason for its' most recent paddy, it's feeling neglected.

Was driving along and the speedo dropped to zero. I've had my old GTi6 do this and it was the sensor on top of the gearbox.

This time however the whole car bogged down for a second. I ran without knowing until I was about 5 miles from home when it started working again. But when it decided to start reading the speed again the whole car kind of 'lurched' forward.

Is this something more sinister than just the little gearbox sensor?

It seemed to be ECU related the way it made the car react. As I say, when I experienced this before on another 306 it just carried on operating as normal. This actually affected the engine a bit.

Any clues? And if it should drop out again are the sensors still easy to get hold of from a motor factors?

Thanks in advance.

[Connor]

Mine used to do this, hasnt in a loooong time. There are threads already on here about it, but basically my theory is that is looses the speed sensor reading, drops back to a "default" setting on the map, just like if it lost the MAF reading, it would set to default. Which is why (I think) you feel the loss and gain in power

[titch]

That's exactly what mine used to do. changing the sensor on the gearbox cured it.

[Eeyore]

Yeh its the sensor on the gearbox. The 1.8 speed needle drops to 0 but doesnt change performance. Im guessing its a hdi thing!