P0717 Diagnosis

[Phillip]

I have a P0717 Input Speed Sensor code on my '96 STS. I have been following Bodybyfisher as he replaced his ISS (along with a bunch of other stuff). That sounds like a hugh job. Before I try something this big, I want to be sure it is the ISS. The shop manual says to check the 20-way connector, but I can't tell which pin is which. It shows pin V and S. Can anyone tell which is which? The connector I am looking at is right beside the transmission filler neck.

[BodybyFisher]

Yes that is the connector, look at the notch on the plug, for the correct orientation. The photo below shows the tranny side plug, Mike

[Phillip]

Thanks Mike. I appreciate the help. If it turns out that I have to replace the ISS, you will certainly hear from me again.

By the way, thanks also for that great discussion of the job you did. It will certainly be invaluable and you are to be congratulated for your patience and perseverance.

Phillip

[Phillip]

I used the picture above to continue the diagnosis but the results are odd. Everything seems to be open circuit. My meter seems to test OK. Which side of the connector is to the PCM and which side is to the Transmission. I assume that the terminals from the connector so I should be able to get a read on the ISS with the Ohm meter, but all I get is an open circuit. Strange.

[BodybyFisher]

Thanks Philip

The transmission side of the connector is where you want to do your testing. Do NOT probe the PCM side of the connector you could damage the PCM.

Use solid wire the approximate size of the pins and put two wires in the appropriate ISS connectors, it will make it easier to attach/connect your meters probes.

Check to see if you have tranny fluid in the connector, I did, and it was wet and dripped for a week after I had NO fluid in the tranny, it kept leaching out. I think what happens is that the wiring harness becomes leaky at the tranny, and fluid wicks down the wires into the plug. UGH.... Another thing I should have replaced, the wiring harness. I found out this was possible AFTER I closed up the side of my tranny. One member even said that the dealer replaced his internal wiring harness, I goofed, but I am thinking of ideas to remedy the situation. The new internal harness would need to be snaked through the tranny to access the entire sensor array.

[Phillip]

Thanks. My connector was spotlessly clean. I hope that is a good sign but it probably means the ISS is the culprit. I checked both sides of the connector by unplugging from the PCM to check continuity from the transmission connector to the PCM connector. I did not probe the PCM itself, or the transmission connector while the PCM was connected. To probe the connectors, I use the pins from an old DB9 computer connector. The male pins fit nicely and the female pins work well with the mail pins on the other side of the transmission connector.