Intermittent Speedo fault - Galaxy....

[catso]

Today driving the Wife's car - 2001 Galaxy 2.3L petrol and Speedo started under-reading/stopping completely.

Sometimes it works up to 40-50mph then drops to 2-3 mph but will work again when brake applied (brakeswitch activating) other times will completely stop and just show 0, Oodmeter also not working when speedo fails and trip computer showing silly MPG (4mpg) due to (presumably) not recording correct distance? also the 'Engine' warning light came on but I guess this is probably a consequence of silly MPG readings?

Car drives fine so thinking it's a speedo or speed sensor fault? any ideas?

[andyquantum]

I'd be going for VSS as well with that

[agentsmith]

one of the ABS sensors or the hub itself providing the "hall effect". a diagnostic tool will tell you which...

[catso]

So does the speedo reading come from a wheel sensor?

[agentsmith]

yep... on virtually all modern cars these days across the CAN-bus network.

[catso]

Any particular wheel?

[catso]

So to update (for anyone that's interested) at the time of the speedo failure there was a faulty brakelight bulb, I have replaced the bulb and everything seems to be OK now - even the engine warning light has reset itself, it was strange that the fault appeared, at least partly to be linked to using the brakes? maybe the bulb was shorting out somehow? anyway all's well again, thanks for the help.

[agentsmith]

catso said:

So to update (for anyone that's interested) at the time of the speedo failure there was a faulty brakelight bulb, I have replaced the bulb and everything seems to be OK now - even the engine warning light has reset itself, it was strange that the fault appeared, at least partly to be linked to using the brakes? maybe the bulb was shorting out somehow? anyway all's well again, thanks for the help.

thats amazing!!

[catso]

Too good to be true.

Well it worked for a while but has failed again, although working now so further investigation required. Funny thing is it only seems to fail when I'm driving it (or so the wife tells me).