Hi,

I know this has been a very common item on the forum, but I have some particular questions which I couldn't trace in the 928 forum :

1. difference speedometer sender type1 (1978-1984) and type2 (1985-88)
2. can type2 also be used for my 1980 928
2. how can sender be tested by measuring how many volts or resistance ?

thnx


Gerrit

 

AFAIK type 1 is a reed relay bolted to the diff cover, sensing magnets in a carrier bolted to the crown wheel/ring gear. Type 2 gets its signal from one of the ABS sensors, so I suspect it isnt actually an extra sensor - just takes the pulses from the ABS unit. Do you have a part number - if its not a 928.... number, its probably generic with othe Porsche models.
What issue are you addressing here? Sensor failure? Thats pretty rare in my reading, its usually a wiring issue, or the speedo head, or the cruise control unit mangling or losing the signal.
Easy to test - locate the connector in the spare wheel well (front , right of centre), put a continuity test across the leads, jack up one wheel and turn - it should make/break 8 (or 9?) times per rev.
jp 83 Euro S AT 52k.

 

I have both types that mount to the diferential in front of me. The only diference is the plug in connector. If you are in need of either, I will gladly list on Ebay for you.

 

I get no speed (km) reading on the dash. I recently restored my car's electricity : all wires on the dash had been cut and wrongly connected by previous owner.
I also reconnected the 2 wires of the sender (red/brown wires) since previous owner had them cut also
Perhaps because the sender was broken ??? I don't know. Thats why I wanted to check this out.

It should be part nr 928-606-210-00...

 

Up until '90 or '91, all senders were simple magnet operated reed switches that rarely fail.

The most common problems by are are faulty connections, either at the connector in the spare tire well or on the flexible printed circuit in the instrument pod.

Remove the cover on the passenger door sill. Find the oxygen sensor warning system counter, and find Terminal G, which will be a brown/red wire. Check that wire for a pulsing signal to ground when the car is moving. If there is no signal, clean the connector in the spare tire well. If there is a pulsing signal, clean the connections in the pod, or check for cut/disconnected wires.

 

Delete

 

WallyP i dont see a brown and red wire in terminal g. what wire number do i connect the multi meter up to and the other wire to the ground? thanks

 

wallyp what wire are you talking about that connects to terminal g?