P0500 / Speedo not working

I bought a lifted '99 XJ a few months ago, and the speedometer has never worked on it while in my possession. I've had other bugs to track down and fix on it, and I'm finally getting around to this.

Despite changing out the VSS, the speedo still isn't moving at all. I pulled the whole housing out to look at the pinion, and the pinion and the splines on the shaft in the transfer case seem to be mint. I've tried to rotate the housing to see if the speedo registers, and that hasn't helped at all.

I'm fairly positive that the pinion does need to be changed out. Currently, the pinion in it has 34 teeth. I think i need a pinion with 32 teeth, as my tires are 31" and has 3.55 gears. However, the speedo still should register a reading with 34 teeth pinion, correct? Also, AutoZone tried to sell me $70 speed sensors for the transmission - it needs two of them - would that be causing this error code? Could the new VSS have been a dud?

Also, I ran the cluster test, and the speedo does respond to that test.

Details about my XJ:
1999 Cherokee XJ SE, 4.0L 4x4, AW4 trans, NP231 transfer case. 3" lift in the front, 2" in the back. Tires are 31x10.5 R15's.

I know on my '96, the speed sensor and housing can be a PITA to register correctly. What I ended up doing was taking the speedo gear housing out, jacking the back tires up off the ground, and clamping a pair of needle-nose vice grips onto the housing shaft. If I thought I had installed it correctly, I'd try giving the driveshaft a few turns. If I saw the vice-grips turning with it, I knew I was in business, if not try again. Once that was all good, install the speed sensor. After a couple times improperly installing everything and going from a shaky speedo needle to a dead speedo needle, this trick worked like a charm.

I would verify the VSS speedo gear at the tailshaft of the transfer case is spinning. Regardless of the teeth, you should get a reading. You need to figure out if it is a mechanical or electrical problem.

1. Mechanical is the tailshaft of the transfer case if the speedo gear is turning. If it is, we need to start checking electrical
2. Electrical is the VSS sensor and associated wiring (let me know if you need the wiring diagrams)

JeepNoob said:

I know on my '96, the speed sensor and housing can be a PITA to register correctly. What I ended up doing was taking the speedo gear housing out, jacking the back tires up off the ground, and clamping a pair of needle-nose vice grips onto the housing shaft. If I thought I had installed it correctly, I'd try giving the driveshaft a few turns. If I saw the vice-grips turning with it, I knew I was in business, if not try again. Once that was all good, install the speed sensor. After a couple times improperly installing everything and going from a shaky speedo needle to a dead speedo needle, this trick worked like a charm.

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I'll give this a try, actually a really good idea. I may even pick up a housing from the boneyard, as this one seems to be a PITA.

5.9longarmXJ said:

I would verify the VSS speedo gear at the tailshaft of the transfer case is spinning. Regardless of the teeth, you should get a reading. You need to figure out if it is a mechanical or electrical problem.

1. Mechanical is the tailshaft of the transfer case if the speedo gear is turning. If it is, we need to start checking electrical
2. Electrical is the VSS sensor and associated wiring (let me know if you need the wiring diagrams)

Click to expand...

Could you post the wiring diagrams? Thanks a ton!

Sorry for the delay. PM me your email, and I will send you the entire Factory service manual for a 2000. Should be 99 percent the same

5.9longarmXJ said:

Sorry for the delay. PM me your email, and I will send you the entire Factory service manual for a 2000. Should be 99 percent the same

Click to expand...

I know this is an old thread but I am having similar issues on a '01 Limited. Could I get a copy of the factory service manual?