ABS/VSS on rear diff

[Josh@DirtyDiesels]

School me on the abs/vss sensor on top of the rear diff. Have had an abs light for awhile and have been neglecting changing it. Scanner shows it is rear sensor. Reason I am asking is today on the dyno I threw a VSS code (p0500) IIRC. Truck wouldn't do over 90 on the dyno after this code and the speedo wasn't working on the dyno. Pulled truck off dyno and took it down the road, speedo worked fine. What does this sensor affect? Shifting? Need some info here.

 

[91turbogsx]

I may be wrong on this but I thought I've read somewhere that if the rear sensor is junk it resorts to using the front wheel sensors. And since it was registering zero mph on the dyno I'm sure the trans/tcm was confused.

 

[HOOV3R]

When the rear sensor faults, it will throw an abs code and switch to the front sensors. I had my harness fail on my axle, my speedo would bounce around for a while. Eventually, it would throw a code and start working normally on a front sensor. I was never limited to speed though.

 

[Josh@DirtyDiesels]

Yeah not sure what mine is doing because the rear sensor was unplugged on the Dyno and its been like that for months. The speedo has never missed a beat until yesterday and my truck was definitely not running properly on the Dyno without a doubt

 

[Josh@DirtyDiesels]

got it fixed today. thanks for the responses. Helped explain why the speedo worked on street but not on dyno

 

[6speedsd]

So I was under the impression that this sensor (in diff housing) determined/aided shifts as well. Is this true?

 

[Josh@DirtyDiesels]

I think it does. On the street with a bad sensor the truck seemed to shift fine. On the dyno with the bad sensor the truck shifted differently

 

[6speedsd]

I'm having issues on the street. Truck seems to go into like a quick shift sometimes. It'll bang all the way through 5th really fast. Then other times it'll hold shifts for a longer period. I had a bad flair on 5, put in GoGo solenoid, and it helped just a small amount. A tune from Eric pretty much stopped the flair. But it still seems like it shifts when it's not supposed to. Thought maybe that sensor could be the culprit.

 

[Josh@DirtyDiesels]

Doubt its the sensor. But to be 100% honest I really don't know. Talk to Eric about it maybe?

 

[6speedsd]

I haven't yet, but I will.

 

[6speedsd]

I didn't make it very clear in my previous post, but it did that quick shift even before the tune. The tune just helped it not happen quite as often. So I doubt it's anything to do with the tune he sent me.