I’ve been trying to track down a solution and I’ve exhausted most of my resources short of taking into the dealer and paying a couple hundred bucks to get it diagnosed let alone getting it fixed. I’m going to try again to find a solution hoping it’s not a bank breaking problem.

my 2001 Limited 2wd with about 155k miles has a fault code of p0500 and the OD light is flashing. No abs light or faults, speedo works fine, and it shifts fine but honestly not as smooth as it should. No other issues whatsoever to report. I know p0500 is the trouble code for the speed sensor. Sensor on the rear diff is working, wiring is good, voltage is good. I traced the wires all the way searching for fraying or breaking and it’s all good. Sensors on the tranny are good as well. All contacts are cleaned and greased properly. I checked the connections on the PCM, checked the OD switch wire in the steering column for fraying, checked for poor splicing into the speed sensor wire for a trailer brake (nothing), checked every fuse more than once. The truck did have a lot of aftermarket electronics installed before I bought it so I’m still sifting through all the wires removing the stuff I don’t need but as far as I can tell none of it would effect the speed sensors. All the grounding points are secure and clean and battery terminals are good and secure. My only thought is a bad PCM but this is literally the only problem I’m having.

Any thoughts or similar experiences? I’m not a mechanic but I’ve learned a lot over the last few years fixing my own vehicles so I would love to get this fixed myself without paying a pretty penny.

Any input is appreciated!

 

I know you said contacts are cleaned but did you clean the end of the speed sensor? Its magnetic and will get a layer of metal shaving that will cause interference. Similar to a magnetic oil drain plug, a good wipe will get rid of it. You usually can't even tell its there since the end is black and the shaving will be black. If you already done this 100% then the flashing is telling you that the code is trigging meaning likely a sensor is going bad.

 

The flashing OD Off light on the shifter is signaling that there is a transmission code set, most simple OBDII code readers can not read these trans codes. I’m pretty sure that Forscan can read the trans codes.

 

Any luck? I am having the same symptoms and can't seems to chase it down.