LLY: Tranny codes P0717 and P0726

[taylorbok]

Hey I had been getting some codes intermittently and recently they have come on full time. Truck shifts hard and then is stuck in that gear and then will often jump to 4th and stay there.
Codes are
P0700 Transmission Control Module (TCM) Requested MIL Illumination
P0717 Input/Turbine Speed Sensor A Circuit No Signal
P0726 Eng Speed Input Circ Range/Perf
C0035 Left wheel speed sensor
C0040 Right wheel speed sensor
B0229 HVAC actuator circuit

I have checked as much of the wiring as I can get to, ohm checked the sensors on bellhousing and trans. Replaced bellhousing sensor, swapped that sensor to trans. Checked TCM connection. Checked sensor wiring continuity. Checked NSBU connection. Checked wheel bearings. Every thing has come up good. I am pretty much stumped.

Any input would really help. Thanks

 

[Ron Nielson]

You may benefit from having a subscription to ALLDATADIY.COM to see the detailed data for all of those DTC's.
If you have a scanner, look at the freeze frame data and see if you find something there that may aid your diagnosis. It is apparent that there are speed sensor problems in various places that are causing your problem and you will have to try to find the problem in an active (truck moving) environment situation. Also, it is possible that you have a sensor or two that either spikes or drops out from time to time that may be your problem. To test that you will likely need a scope to be able to find those problems. If you are not familiar with this, look at Youtube and look for brake sensor videos by South Main Auto to further understand what may be happening to your vehicle.

 

[taylorbok]

I really don't want to take it in if I can avoid it but I am nearing a loss. What is the final speed sensor supposed to ohm at? (the one on the tcase) I just checked it for the first time and only getting 1.5k ohms out of it, I assume it should be the same as the others at 2.3-2.8k ohm

I also assumed that if it wasn't working properly I'd be seeing weird shit with the speedo? speedo seems to function fine

 

[taylorbok]

I found the rubbed wires, Under neath the front of the fuse box where the harness clips to the inner fender the 2 sets of twisted pair wires that go to those tranny speed sensors and one other green wire had rubbed through, the orange one was almost completely through, must have been causing intermittent voltage drop.

pulled the harness up and spliced in some new wire and she is good and driving again.