Variable Speed Sensor / Speedometer

[kwj929]

1995 GC: My speedometer does not work. I am getting fault code 15, so I replaced the variable speed sensor at the transmission. It didn't effect anything. I wonder if the VSS square shaft that fits into the transmission housing is not rotating because the piece that it fits into is stuck? I only replaced the VSS (which spins freely) but I'm not able to know if the mating receptacle inside the transmission is actually rotating and thus spinning the VSS as it's supposed to. Is it possible that it somehow is stuck inside?

[Cam7]

Its possible that there is a problem inside the Trans. First check the wirring comming from the sensor to make sure there are no Breaks in the wires.

[kwj929]

Thanks for the suggestion. I beeped out the three wires between the VSS connector and the PCM computer connector under the hood... all good. Now get this... I decided to be daring and removed the VSS mount from the transmission. It was quite simple (but i didn't know what to expect). There is simply a gear which mates with an internal gear of the transmission. The VSS mounting is designed on a eccentric circle such that if you rotate it, it will eventually engage the two gears. The problem was that it was mounted wrong by 90 degrees! The gears were not engaging whatsoever. Thanks to Aamco who was trying to fix my "Limp mode" transmission problem, they had also supposedly replaced this sensor but had somehow rotated its mount. What frustration. At least my fault code 15 is gone now. In any event, they also had replaced the governor solenoid which hopefully will help rid me of the intermittent problem of starting out stuck in 3rd gear.

At least now I'm back to my original problem (before Aamco) of the speedometer which now sometimes works and sometimes does not. I think it may be a problem at the gauge because I notice now that if I tap on the odometer reset button enough times, sometimes the speedometer will come back alive...

[Cam7]

When the speedometer isnt working try pushing in on the guage and see if it will work could be a bad guage or connections behind. I didnt think of someone removing the sensor and not installing it right. Did your speedometer problems start at that time? If it did try reseting the computer by un hooking the battery I dont know if they could have screwed it up by not rotating it in the right allignment.

[rpady]

Originally Posted by kwj929

. In any event, they also had replaced the governor solenoid which hopefully will help rid me of the intermittent problem of starting out stuck in 3rd gear.

At least now I'm back to my original problem (before Aamco) of the speedometer which now sometimes works and sometimes does not. I think it may be a problem at the gauge because I notice now that if I tap on the odometer reset button enough times, sometimes the speedometer will come back alive...

Did the governor solenoid fix the 3rd gear problem? Ours does the same thing along with the speedo being intermittant. Please let me know, thanks, [email protected]

[kwj929]

Originally Posted by rpady

Did the governor solenoid fix the 3rd gear problem? Ours does the same thing along with the speedo being intermittant. Please let me know, thanks, [email protected]

Here's the latest... Fortunately, the transmission seems to be shifting properly now. I attribute the solution to be the replacement of the gvnr solenoid which Aamco transmissions had done. The only problem was that the Aamco people had re-installed my speed sensor improperly (after having removed it to check it out...) which was giving me engine codes when I got the Jeep back. Ever since the time that I installed the speed sensor the right way, I haven't had any more shifiting problems. The shifting problem was not caused by the speed sensor, but evidently the solenoid. I never got to look at the solenoid itself, and how to remove it, because Aamco did that part. I still have the intermittent problem of the speedometer cutting in and out, but I haven't tackled the task of pulling out the dash to look at what's behind there (I hope it's a connector problem or something simple).

[Audiobahn77]

pulling the speedometer is super easy and rather quick. in my 97 you remove the two wood trim pieces and the 10 screws. Pop the trim bezel out and the four bolts that hold the speedometer in. Next, you CAREFULLY pull back towards you the the whole cluster. From there you can inspect it and/or reseat it.

[LC1974]

After much searching I found this informative forum. I also have a '95 GC with this exact same problem. I changed the "turbine sensor" at the tail shaft of the transfer case. This didn't help. Also found there is another sensor on the lower left side of the transmisson. I changed that and still the same problem exists. I'm now guessing a simple connection proble is apparent, but where. I know this is an old thread but did anyone find out what is causing this?

[dksob81]

Originally Posted by LC1974

After much searching I found this informative forum. I also have a '95 GC with this exact same problem. I changed the "turbine sensor" at the tail shaft of the transfer case. This didn't help. Also found there is another sensor on the lower left side of the transmisson. I changed that and still the same problem exists. I'm now guessing a simple connection proble is apparent, but where. I know this is an old thread but did anyone find out what is causing this?

There should be 2 sensors, 1 speedogear sensor (tailhousing of the transfer case) and 1 Vehicle Speed Sensor (on the transmission). If your speedometer is not working it could also be the wiring going from the somputer to the dash, is you look above the PCM (behind the coolant overflow bottle) right above it there is a round connector wiggle those wires around make sure the center nut it tight.

[LC1974]

Originally Posted by dksob81

There should be 2 sensors, 1 speedogear sensor (tailhousing of the transfer case) and 1 Vehicle Speed Sensor (on the transmission). If your speedometer is not working it could also be the wiring going from the somputer to the dash, is you look above the PCM (behind the coolant overflow bottle) right above it there is a round connector wiggle those wires around make sure the center nut it tight.

Here's my update: I disconnected and checked the connectors to: the PCM, the big round connector next to the PCM, the ground from battery to engine and all 2 and 3 wire connectors I could find. I took it for a test drive and the speedo worked fine. I stopped, went into a store, started driving down the road and the speedo didn't work. It started working after about 2 miles. I'm really stumped now.