m3vs911

hi mates, hope you are all doing good.

my 90 c2 has a funny speedometer problem recently. it quit everyday in the morning when I start the car, I tried patting it, take it out and shake it, ensure the plug is connected. they wont help much.

however, the speedometer will get back to life after a period of time driving. say 10 15 mims drive.

so I bet it is not the gauge problem itself ? cuz I believe if it's mechanically problem then it should not be working at all.
I tried to check the dme relay but it doesn't help too.

the pulse sensor has been replaced last year ...( unless it has become faulty again ?) or loosen.

thanks for all advices.

Arthur

Silvertarga

One of the relays in the fuse box (and I dont remember which one) has been known to cause this, try cleaning the contacts of the relays and reinserting them..also check connections at transmission/sender

m3vs911

thanks for the advice but i've check most of them (relays) and they are fine.

still any possible ideas?

It's really funny to have the speedometer back in life after a 10-15 mins drive.
just before the speedometer come back to life (if i am driving 60mph+ , and the spoiler is deployed),i reckoned the " ! " sign will be shown for 1 sec.

thanks for all helps
x

jimq

clean the contacts real good on the back of the speedometer. They have been known to do this. they may look clean but it doesnt take much corrosion to make it not work.

sschultze09

Arthur, try this thread. Seems to be a common problem.

https://rennlist.com/forums/964-foru...s-working.html

Good luck!

jorijori

Hi Arthur,

I just got this fixed yesterday, on my triptronic car is relay 52, the blue one inside the fusebox, I will get the part# for you tomorrow ( bed time now). Speedo was bouncy & worked intermitently.

On manual car is a different part#, if you have Adrian book, is in there in speedometer troubleshooting section.

jorijori

Part# is 964.618.220.00 & Type.911.co.uk has a used one for £35, new one is £175.

n.dino

I'm in the same boat. First, I tried the ABS relay- no luck. Today, I thought I would fix the job with a frequency control unit (relay #52) and nothing. Abs light is on, speedometer doesn't work, odo frozen, and wing doesn't work. What to do next?

P.S. My car is a 92. I believe there is a difference in the 92+ cars with relays, etc.

911PERVY

964.618.220.00 fits all 964

boxsey911

If the ABS light is fine when you fire up the engine but then comes on as soon as you drive off, all of your symptoms indicate a problem with the front left ABS sensor on the wheel hub, as that's the one that provides the signal for the odo on late cars and the signal for the spoiler light. Cleaning it might solve the problem but it's more likely that you'll have to replace it.

sc

Hopefully the OP can update this thread if and when he resolves the issue. Mine exhibited similar to what he describes but no ABS lights just dead ODO and spoiler light. Mysteriously went away and has been working since but afraid it may eventually resurface.

m3vs911

I am still working on it. just wondering the speed sensor, where is it located at? do i have to take off the wheel liner to get accessed to it?

jimq

Did you try cleaning the contacts on the plug in the back of the speedo like I mentioned previously?

jorijori

Hi,

Not the liner but you have to remove the wheels to access the speed sensors, they are bolted so you need to remove a single bolt on each sensor. They are behind the brake calipers, you will see a cable connected to it.

I say don't bother, the most likely culprit is relay R52.

n.dino

The ABS light comes right on when I turn the engine. That being said does that cancel out the left ABS wheel sensor?