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speedometer failure and ABS sensors

coopab

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First off, I read the Jim Oaks' sticky thread.

Problem - "The speedometer in my 1999 Ranger fluctuates or doesn't work until I hit 30MPH. What's wrong?

I just finished replacing BOTH front hub/bearing assemblies with non-ABS and after replacing the driver's side I took a short test ride and the speedometer was working. I did the passenger side yesterday and today (Had to go to a Ford dealer for a replacement axle retainer snap ring). I used non ABS bearing/hub assemblies because the ABS has never worked in the three years I've owned the truck. Previous owner told me he had replaced the rear ABS sensor. Speedo has always worked but no ABS.This time the first thing I noticed when I went on test ride was NO speedometer. Tach is fine. I suspected that the now disconnected passenger side ABS sensor was the cause.

I don't think it's worth buying another new hub (or set of hubs) Any comments or suggestions??

P.S. While I was at it I did the "push button mod" to get my 4WD working again. Yay, it works!
 


RonD

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1998-2000 Rangers used the ABS speed sensor in the rear differential for speedometer and other systems, has nothing to do with the hub wheel sensors.

The 2 wires from the speed sensor go to the ABS Module, the module is programmed for tire size and rear axle ratio(actually it is just revolutions/mile), ABS module then sends out the corrected speed signal to computer, GEM, speedometer and cruise control.

If you have 4 wheel ABS and removed front wheel sensor then ABS light would be on but speedometer would still work.
If you unplugged the ABS module then speedometer would not work
 

coopab

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Well, I replaced the rear speed sensor and still have no speedometer and odometer. In addition my cruise control is AWOL. As I mentioned in the original post, the speedometer and odometer stopped working when I unplugged the right front speed sensor and replaced the wheel bearing/hub with a non-ABS type. I didn't notice the lack of cruise control until recently as I hadn't had reason to use it.

I have several other unrelated issues that have cropped up so I won't be trying to replace the new non-ABS hub with an ABS one until I solve those other problems. In the meantime here's what my new ELM327 OBD code reader reports about the speed sensor problem.

P0500 - Ford

Type Powertrain - Vehicle Speed, Idle Control, and
Auxiliary Inputs - ISO/SAE Controlled

Description
Vehicle Speed Sensor Fault Conditions

Cause
Engine running, engine speed above the TCC stall speed, then the PCM detected a loss of the VSS signal over a period of time The PCM receives a VSS signal from the VSS, TCSS, ABS Module, GEM or CTM (central timer module)

If any of this suggests a solution that doesn't involve expensive parts please weigh in.
 

RonD

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P0500 means the computer is not seeing the "speed" signal from the ABS module.
Neither is speedometer
And neither is Cruise amplifier
These are all sent the VSS signal via the WABS module

So the three things that could be wrong, are VSS, WABS, or Wiring .
You tried a new VSS, so assuming the tone wheel inside the axle housing is OK then that leaves WABS module or wiring.

When you unhooked the front wheels sensor you noticed speedo had stopped working.
I don't think that should happen, so I would think WABS module has the issue
 

coopab

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RonD,

What does the W in WABS stand for? And is this the part referred to?

Prior to changing my front wheel hubs I had no speedometer or cruise control problems. Is it possible, or likely, that the wiring that I disconnected from the old hubs could have caused a problem with the WABS module?
 

RonD

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Sorry, 4WABS, 4 wheel ABS

Possible but not likely, people lose wheel sensors all the time from broken wires or sensor failure, and I have yet to read that the speedometer stopped working at that time.

The VSS signal is a separate thing from the wheel sensors, 4WABS uses the VSS pulses, and compares the wheel sensors to the other wheel sensors and the VSS.
 

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