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I've read as many forms as possible and it seems like a common ish issue. But the speedometer and odometer are not working on my 99 f250 super duty 7.3. The tac doesn't move on the speedometer and the numbers don't rotate on the odometer and the reset bottom doesn't work. Is it possible that its not getting power at all? My abs light is on (turns off after a reset but comes back on quickly after starting) My OD light is flashing (over drive does work).
Here is the symptoms /issues that are going on:
Speedometer and odometer not working
Abs light on
OD light flashing (but works)
Seems like it shifts fine
Here is what I've done so far:
Replaced speed sensor on the back diff
Replaced/checked all fuses
Reset the truck.
Does anyone have any possible things I could check that are kinda easy (I'm mechanically inclined but not even close to an expert)
Also, does it hurt the truck at all to run it like it is?
In the top of the pinion side of your rear differential will be an electrical plug and a speed sensor. Most likely the wires leading to it have been damaged preventing the data being received by the pcm. Could also be a failed sensor but wiring is more likely and free to check. that should fix the speedo and odometer, od light should clear, and possibly the abs light. If that's how the abs is tracking wheel speed in the rear then should clear. Might check brake fluid in master cylinder if it doesn't, those will throw a light if low.
We can not do anything without the codes. Pull them, record them, erase them, then pull them again.
Get FORScan or FORScan Lite and the recommended OBD II reader. Follow the instructions for the program.
When it comes to sensors and control items for these trucks you are going to buy twice and cause more problems if you use anything other than Navistar or Motorcraft for almost everything on these truck.
No Cramazon or Fleabay and be careful about the stuff at the corner store.
By the way... This is the second time I have typed this tonight.
OK, I have replaced the speed sensor already. Is there a way to test to see if there is a broken wire between the speed sensor and power sourse? I'll have to get a reader and see what codes it is throwing.
On the drivers inner fender back towards the firewall are 3 large square plugs. One of those will have the wires for the sensor if you knew which pins in which connector you could check conintinuity. Comer to think of it those plugs can be a source of wiring problems themselves. I would start at the sensor and pull the loom a little at a time checking for damage. When mine had these problems it was one of the wires worn nearly in two at one of the support hangers for the loom.
My abs light is on (turns off after a reset but comes back on quickly after starting) My OD light is flashing (over drive does work).
You have DTC's (codes) stored or active for the ABS module and for the transmission that should be read and identified. These codes will help us find you a solution or at least point you in the right direction. Most parts stores are NOT able to read the transmission codes, but the thread below by FTE'r BWST will help you find a method by using FORScan or FORScan Lite.
I would strongly suggest and urge you to have these codes checked and noted prior to spending any more time or coin on the issue at hand.
In addition to the advice offered above, I would offer the images and documents below which I found via a search. Are there any codes
Attached is the VSS (speedometer sensor on the differential) pinpoint test. You may not be able to accomplish each step, but they should give you an idea of what you are looking at/for.
The only diagrams I could find during my search were for a gasoline specified vehicle where the VSS is referred to as the DSS (differential speed sensor).
Although, some of the connectors and circuitry are identical across the gasoline and diesel trucks. So, the wire color code and junction/termination points may be the same as indicated in the diagrams above. As you can see, the DSS/VSS is tied directly into the ABS module, which you have a fault with in one way or another. In addition, there are speed sensors on the case of the 4R100 transmission that may be playing a part in your speedometer and odometer failures.
I hope the advice from the other FTE'rs and what I have written helps you out. If not, come back to us and we will take another swing at it.
Thank you so much guys, I got a code reader on hold at the store to give it a try, if it doesn't work I'll order the forscan (I just didn't want to wait the week for shipping) and report back with the findings. I'll also start working my way back from the sensor to check wires. Thank you all again.
Well the scanner didn't pull any codes so I have the forscan adapter coming. Will be here the 11th
Our trucks have an OBD II port but they are not OBD II compliant and there are not many scanners that will work with them. There are a couple of popular dongles here and either ForScan or Torque Pro with ForScan being better for diagnostics.
Our trucks have an OBD II port but they are not OBD II compliant and there are not many scanners that will work with them. There are a couple of popular dongles here and either ForScan or Torque Pro with ForScan being better for diagnostics.
Thanks walleye, hopefully it comes next week. It will be my first time playing with them. Anything I should know about forscan before I mess with it?
Thanks walleye, hopefully it comes next week. It will be my first time playing with them. Anything I should know about forscan before I mess with it?
I'm the wrong guy to be asking for help with that LOL. Plenty of others here are very proficient with it though and they will set you straight. Good luck.
Thanks walleye, hopefully it comes next week. It will be my first time playing with them. Anything I should know about forscan before I mess with it?
Check out the following links, especially the last one.
FORScan is far superior to anything else that we have available to us as shadetree mechanics and consumers. Don't use TorquePro to troubleshoot, it is not your friend. Car Gauge Pro works pretty well from what I understand, but FORScan or FORSCan Lite is your best shot at getting this thing sorted out via an OBDII scan tool.
