Porsche Enthusiasts Club Forum

You'll find it's invaluable geo. Ask away on there with your query and check the response - it's a fantastically supportive forum.

I believe it works like this (although I've never done it myself):

For each sensor - first you test between the two pins for the sensor (to check there's a complete circuit from the ECU out to the sensor and back again), this tells you either (A) that the sensor is probably OK or (B) that there's some unknown discontinuity in the circuit.

If it's (B) then you can test between one of the sensor's pins and ground, if you can measure a finite resistance then it suggests that the discontinuity is due to a short to ground, if the resistance is infinite then the discontinuity is due to something else (broken wire, corroded connector etc.)

So, if you just test between one of the pins and ground without performing the first test your conclusions will be either that there is a short to ground or there isn't - if there isn't, it still doesn't tell you if the sensor is fine or if there's some other discontinuity.

In other words, you have to know which pair of pins corresponds to which sensor - otherwise do your testing at the individual connectors for the sensors themselves.

Sorted.... ABS and tyre pressure warnings both gone

Turns out the right rear speed sensor connector had worked lose from the cylindrical 3-way connector on the hub, which wasn't properly secured in it's black plastic holder.

Ok next on the list......