ABS light and crazy speedometer.

[Dora2007]

1994 Aerostar. Had ABS light and speedometer went crazy above 60 MPH, onset kinda near the same time.

Researched on web. Some say speed sensor on transmission tail for speedo, some say ABS sensor on rear axle runs ABS and speedo.

I have NO part where manuals and YouTube videos show speed sensor on transmission tail.

I did change ABS sensor on axle and ABS light no longer on, but speedo still acts crazy > 60 MPH.

Questions:

1) Can you confirm, yes, with NO part on transmission tail, ABS sensor runs both ABS and speedo, or, speedo sensor is <insert place here>. Remember, NOTHING is present on transmission tail.

2) Plenty of other causes for crazy speedo, and therefore, if ABS light is out (fixed), just live with speedo, or keep under 60MPH (hard to do).

3) Any ‘storage’ of speedo info in memory, so disconnect of battery to clear memory would help?

Thanks

 

[Josh P]

Speedometer gets the signal from the rear axle. If your van has cruise control and it is still functioning then I'd suspect the psom.

 

[Dora2007]

Sorry to be doy ...

Programmable Speedometer/Odometer Module (PSOM) - is this a separate box and if so where is it, or is it the big dash gauges-lights-dials that I would call the ‘instrument cluster’ - the thing you look at?

 

[Josh P]

Sorry to be doy ...

Programmable Speedometer/Odometer Module (PSOM) - is this a separate box and if so where is it, or is it the big dash gauges-lights-dials that I would call the ‘instrument cluster’ - the thing you look at?

It is inside the instrument cluster behind the speedometer. http://www.supermotors.net/registry/media/76023 Down toward the bottom of the page is some good info.

 

[BrooklynBay]

Check the PSOM, wiring going to the rear ABS sensor, reluctor ring teeth, and the wiring in the steering column near the tilt mechanism.