964 faulty speedo problem????

Keith Calder · Jul 15, 2004

wondered if anyone else has had a faulty speedometer? after i leave my c2 for a couple of weeks with the battery disconnected the speedo and the digital speedo in the rev counter doesnt register. although its not a major problem in itself the spoiler warning light comes on and the spoiler wont rise automatically, the abs warning light also comes on and the warning beeper sounds.. after a few miles the speedo works again and everything goes back to normal...im guessing its a bad sensor in the gearbox but before i drop off the undertray is there a relay in the fusebox worth checking or replacing ?cheers

Jon Kent · Jul 22, 2004

I had the same problem last winter, and again, it rectified itself once the car was warm. It only occurs when the car is left outside in the cold or in a cold garage (around 0°C or less).
Was told by Roock in Leverkusen it was just a sensor issue. They cleaned it, but it's summer now, so never happens anyway. Hope this helps some......
Rgds,
Jon

Keith Calder · Jul 22, 2004

thanks for your reply jon, im willing to take the car to a garage for repair but the fault cures itself before i get there, might wait till it gets worse cheers

Guest · Jul 23, 2004

I also had the same problem - but it was only in the winter when the car was cold and damp - a little tap on the speedo face put things to rights. Hasn't happened at all since weather warmed up.

Debs

Keith Calder · Jul 23, 2004

hi Debs i tried driving round the block with the speedo pulled out the dash so i could give it a shake and push in the plug at the back but that didnt work which made me think the problem is the sensor on the gearbox, glad you managed to fix yours with a tap.....

Keith Calder · Jul 24, 2004

just read an article at www.porsche964.co.uk about dash warning lights coming on due to dry solder joints on the clocks, worth a read........

Keith Calder · Aug 13, 2004

though id post an update, i managed to borrow a spare speedo from a friend and carried it with me in the car, of course my speedo started working perfectly..... for 25 miles at least and then it stopped while doing 70mph (ish) i pulled over and swopped the speedos over and drove off, no difference!!! im taking the car in to have it checked next week. im expecting a bill for a new gearbox sensor......

Guest · Aug 14, 2004

Shoked to see a complete strip down of the speedo in this months 911 world. Made me go humm when I read the title but the bit that bothered me the most was when the caption said ' this is where you could change the milage'!!!!!!!!!!

So a detailed description of how to clock your car across two pages with pics.

Keith Calder · Aug 18, 2004

got a lot of time for keith seume, guess he was trying to help folks fix a common problem, some people do zero a speedo after a complete restoration i suppose??? see your point though or do people doing that sort of thing already know how to anyway??

Keith Calder · Aug 19, 2004

Talking to myself on this thread!!!!! anyway getting back to the first question IS THERE A RELAY IN THE FUSE BOX TO CHECK? well yes actually....my mechanic tested the car and found the speedo on the late 964 is driven through the abs so the fault was the abs not working, so not giving a signal to the speedo, i panicked about the cost of an abs control unit but after checking it out a new abs relay did the job . shame about the couple of hours labour , so check your relay first... THE END