I bought a 93 f-150 6cyl. 120000ish miles. I have fixed most of the problems except for this one. odometer is reading ( error.3) the man had a break in the electical supply to the interior with a fuse and wire.Got rid of that and now I need to get rid of the error message. I tried unplugging the battery and that didn't do it. Any one have any ideas????

 

You might have to take it to the dealer and get them to do some hokus pokus with a scanner or something to get it going. They have a lot of interlocks and procedures nowadays to thwart thiefs and roll-back artists. Of course they all probably have the necessary equipment to fudge the readings anyway.

 

It just needs to have the conversion constant reset.



Reprogram speed conversion constant using the following procedure:

-- Locate the dealer mode programming enable single-terminal connector. The connector is located at the bottom of the instrument panel below the center of the glove box. On all vehicles, the dealer mode enable wire is Circuit 567 (LB/Y).

-- Insert metal clip in service wire panel connector. Clip other end to vehicle ground while the key is in the OFF position.

-- Key to RUN while holding down the trip odometer RESET button on speedometer. Release RESET button.

-- Speedometer will prove out (sweep across dial and back). The English/Metric and revision levels will be displayed. The last number of the display is the dealer mode programming lockout count. This count shows the number of allowable conversion constant changes remaining. When the count is zero (0), no additional changes can be made to this instrument cluster. If a conversion constant change is required, a service instrument cluster must be ordered.

-- Press and release RESET button again and PSOM conversion constant (without the decimal point) followed by the word CAL will be displayed.

-- Press and release the odometer SELECT button as many times as necessary to change conversion constant to the correct value.

Note: Pressing and releasing the RESET button to lock in the new conversion constant reduces the number of times the PSOM can be reprogrammed by one count. The module can only be reprogrammed six times. If you change your mind and want to go back to the old conversion constant, turn the key off before you lock in the new constant.

-- When the correct new value is displayed in odometer window, press and release the RESET button to lock in the new conversion constant.

-- Key off. Remove the ground wire. Verify proper speedometer operation



Get back to me with your tire and axel info, and I'll give you the conversion constant.

 

Thanks for the help my tire size is 32x11.50 r 15lt

and it looks like the rear is 3.08

 

Screwy fixed my problem .My hat goes off to him and everyone who tried to help me on this web site.

 

Rgiven, To find your exact constant use this formula: (Tire revs per mile X Tone ring teeth) / 8000 = Constant

Your rear end should be an 8.8, and they had 108 tone ring teeth.

Try and find the exact revs per mile, sometimes it can be found on the manufactures website.

My guess:

32in X 3.14 = 100.48

63360in /100.48 = 630.57

(630.57 X 108) / 8000 = 8.51 (rounded)

Constant = 8.51


You can go with my guess or try and get a more accurate one.
Once your done, I would have a buddy pace you to double check that it’s close.

p.s. sorry it took so long to reply

 

hey no problem. I was praising your name Monday. I found the constaint for p235 70 r15 . That's what I normally run. Any way I put the number in and the error went away, and the truck seems to even be running better if that is possible.
When I went to just look at what the constaint was (with out the wire ). It said 1000 and the cal was flashing. right then I knew you were right. Anyway thanks a bunch. I will keep your mathmatical works in case I ever need it again.