Hello all, I have a 1997 Ford F250 HD 4X4, which in reality is a 1996 body style truck that was made in 1997, I have heard some people refer to it as the old body 1997 as it was as split year. The truck has a 351 engine and automatic transmission with the OD button on the end of the shifter handle. I have lifted it 6" and use it as a hunting truck primarily.

The check engine light has been on since I have owned it (about a year) but it has the old OBD1 connector under the hood over the driver side inner fender well, and my OBD2 scanner would not work with it, the truck seemed to run fine, however the exhaust would smell a little rich at times. I drove it this way for about a year with no issue.

One day a few months ago I drove it with no issue, then very next day I cranked it and noticed that the odometer was not displaying the milage of the vehicle, it was back lit, but not displaying the numbers. As I moved in the yard I also noticed that the speedometer was not working whatsoever. When I got out on the road the truck shifted very hard from 1-2 and 2-3 at which time the "off" light at the end of the shifter handle began to flash, and the truck was shuddering as if it were trying to shift in and out of OD.

I replaced the speed sensor, it is located on the rear end, and I am told it is also the ABS sensor, the ABS light was not on, and changing the speed sensor did not fix the problem.

I borrowed a cluster out of a 1995 F150 that looked identical to mine and swapped them to see if the PSOM had given up the ghost in mine, the cluster out of the 1995 works in the 1995 fine, but has the same symptomes in my truck as no odometer reading and no speedometer movement. I assume that rules out the PSOM itself, I have checked all the fuses in the cab and under the hood, I can not find a bad fuse that relates to the speedometer, my next step is to check power at the PSOM connecter I guess, I haven't done that yet.

I purchased a now scanner that is OBD1-2 and the codes I am getting with the Key On Engine Off scan are for the EGR valve having low flow, and the speed sensor, however the scanner will not link during the Key On Engine Running scan.

I am a little at a loss, I could have a bad (new) speed sensor, the PSOM may not be getting power, or I guess it could be the computer having issues if it will not link to the scanner when running, I am not sure which way to go.

If any of you have any input or advice I would sure appreciate hearing it, does anyone know where the odometer reading comes from? would it be affected by the speed sensor or would just the speedometer be affected? Thanks in advance for any help.......

 

First I will say that the OD light flashing and tranny shifting hard is probably a different problem than the one with the cluster. Ford made a limp mode for the trucks when something goes wrong with the tranny. When the OD light blinks the E40D is in limp mode so you can get home.

Read these for the MLPS/E40D and scaning problems:
https://www.ford-trucks.com/forums/2...-the-mlps.html
How-To: retrieve trouble codes- OBDI - Ford F150 Forum - Community of Ford Truck Fans


As for the cluster someone else will have to help you with that b/c I'm more familiar with 80-91's...

 

The reason I tried another cluster is because this truck has a PSOM (programable speedometer odometer module) that is mounted to the speedometer back. It is my understanding that the speed sensor on the rear end goes to the PSOM, which runs the speedometer, then the signal from the speed sonser leaves the PSOM and goes to the PCM for other control of the trans shifting and such. If the PSOM dies, you don't get the speed sensor signal to the PCM as far as I have been able to find in my online research. PSOM's are no longer available for my year model, you can have them rebuilt, but it is pricy, so I tried one from a similar model to see if it fixed my issue, which it did not.

 

Mossyhorns - ddid you ever resolve this issue? We have the same truck - problem and all.

 

Check for a blown fuse or cut/chafed wire - my 350 has a remote start system that does not power all the cabin circuits by itself. While the remote start system is on or running the truck but before the operator inserts and sets the key to on, the instrument cluster behaves as you describe.