Hi All,

I"ve been dealing with some transmission issues for the better part of a year. I'm looking for some advice on what to try next. Here's the issue:

I have a 1997 F250, 5.8L. I drive the truck sparingly - just for trips to the dump, or clean up brush, or to Home Depot. Intermittently over the last year, the overdrive light on the gear shift will start blinking and the truck will go into "limp" mode. The speedometer and odometer stop working at that time, though the ABS light stays off.

Here's what I've tried: I've replaced the VSS and the VSS harness. I took the truck to the dealer, but they wanted to replace the PCM because they couldn't get codes from it. However, I CAN get codes from it with my own OBD I reader.

Any thoughts/suggestions would be much appreciated.

Thanks!

 

Pull codes and report them here.

 

Sounds like a PSOM problem or power and grounds to the PSOM.
The odometer stop working would have nothing to do with the VSS in the rear end or its wiring.

 

Codes are as follows:
622 - Shift solenoid #2 Circuit Fault
172 - 02 Sensor Fault/lean
452 - Vehicle Speed Sensor Signal Fault
542 - Fuel Pump Secondary Circuit Fault

 

It would have been nice to know what type of codes you got (KOEO, CM, KOER)

I will make some guesses not knowing the type of code you got.
With the odometer stop working we knew you would have the CM 542 code and as I said with the PSOM quit working and that sounds like a bad PSOM or lack of power to it or the lack of ground to it.

The 622 if it was a KOEO you have an electrical problem between the PCM and the #2 shift solenoid circuit or solenoid.

The 542 could be from a fuel pump test by running the fuel pump without the PCM knowing about it or a bad fuel pump or its circuit.

172 lean could be from the fuel pump being bad.

 

All of the codes were KOEO, but the last three were after the "10" separator.

Thanks for the analysis so far! I think the VSS code and the O2 sensor codes were from before I addressed those issues. No idea about the fuel pump code.

 

The "10" separator is between the KOEO and the CM codes.

The 452 is only a CM code.
The codes in CM will last for about 60 start ups or you can clear them by taking the ground away from the STI wire when the MIL starts to flash.

KOEO DTC 622 indicate solenoid did not change state when requested by the Powertrain Control Module (PCM).

Possible causes:
-- Damaged solenoid/assembly.
-- Open or shorted harness (internal/external).
-- Damaged PCM.

 

How would I go about tracking this down?

 

I would start by unplugging the connector on the passenger side of the transmission, take the back cover off the plug and examine the wires going into the plug.
If everything looks OK unplug the PCM plug and check continuity on the SS#2 wire while shaking the harness.

A BOB or a transmission tester would help if you happen to have one.
If you have continuity then plug the transmission plug back in, leave the PCM unplugged, turn on the key and quickly short the SS#2 wire to ground off and on an see if you can hear the solenoid making a clicking sound. Do not leave the SS#2 shorted to ground for more than 1 second. If no clicking sound change out the solenoid pack.

 

Thanks for the help! I'll try what you've suggested and see how it goes.