Porsche Enthusiasts Club Forum

Hi peeps, i recently bought a 944S but the speedo doesn't work (I have done searches btw). The speedo and odometer both don't work nor does the odometer trip reset

I have checked the connections behind the speedo cluster many times and have cleaned/ checked the speedo sender at the transmission. I'm stumped..

does it sound like the speedo guage at fault because the odometer trip doesn't reset. Is there a way to fix this? I can't seem to find any information on testing the speedo guage itself and those terminals?

There should be power on the speedo head & a pulse from the transaxle sender. Really this needs checking with an Oscilloscope. Where are you as I have a spare speedo head I could lend you as a tester? I might have a sender on the spare transaxle in the garage thinking about it. But I'd pretty much think it will be a bad connection.

Thanks Jim, but i live near Cardiff which is miles away from Kent

Do you means connections behind the speedo cluster? I've pried all those teminals with a compass so they get a better contact but it didn't do the trick It's stange that my trip reset won't reset the trip counter either which leads me to believe that it's not the sender at fault.

I'm thinking of taking the speedo guage out from the cluster to inspect but... i wouldn't know what to look for tbh

Trip reset problem is usually caused by the reset unit behind the dash vent moving out of line with the reset button built into the dash vent, mine stopped working and while I had the dash out to change the lamps I re-fixed the reset unit to align with the button now it works fine so may not be a linked problem.

It sounds like the speedo sensor in the gearbox or a bad connection on the cable from it.

Cheers Dave ive just reset the trip odometer with the vents removed. At least i know it's not totally knackered.

I also removed and rechecked the sender at the tranmission but no joy. I've bought a 2nd hand sender from eBay, hopefully that will sort it out

Glad the trip reset works as you say not totally knackered and shows there is power to the unit. If the replacement sensor does not fix it I would check the cable from sensor to dash with a continuity tester to see if there is a break in it.

Right my 2nd hand sender is here.. turns out the bit in the middle of the sender had broken off and stuck in the plastic bit which is held down by the boss



does anyone have a spare one or know of a part number for that plastic bit with the built in cog, please?

Update, i ordered the platic cog thing (speedometer pinion) £4.21 from Porsche!

i fitted it along with my 2nd hand speed sender and it's now working

it's a bit intermittent i.e. the needle sticks.. have to tap it to get it to respond. Thanks guys for your input esp. Dave else i'd have wasted money buying a replacement speedo

Glad it is working, my speedo sticks & so it seems do a few others. I'm told it is commonly a bad connection on the speedo.

Mine used to stick but the more I used it the better it got. Now perfect! Can't explain why. Replaced the sensor & it made no difference. Regular use all it needed. Used to have to slow right down for speed cameras as it didn't work below 35 Sometimes it's better not to know.