Hello all. New to the FTE. I recently bought a '92 f250 2wd w/5.8 and e4od trans. This is my first OBS so this has been a fun experience so far. The turn signals haven't worked since I bought it and the trans shifts hard but works. I had an intermittent RABS and CEL but never the OD light blink. I changed the VSS(not Motorcraft but Auto Zone) first with no results. I learned how to pull the codes and got the 625 and the 452. Checked all fuses and connections, no blown fuses and cleaned and greased connections, nothing obvious there. I ordered the
solenoid block for the trans. When it came in I dropped the pan, installed along with fluid and filter(drained the TC too, 16 quarts total) Old fluid didn't look bad, pan was clean, the magnet only had a very light layer of "dust" on it. The day before the part came in it tried to die out when coming to a stop like the TC didn't want to unlock. After the trans service, when I put it in D it won't upshift on its own. When I take off in 1 and manually shift into 2 its fine, but when I manually shift into D it starts slipping and doesn't feel like its trying to go into 3. Pushing the OD button does nothing but the light does go on and off. Now I am getting a 452(VSS) and a 536(Brake on/off switch) I am pressing the brake for the test. I do not have the 3rd brake light, but my brake lights do work. I also ordered a multifunction lever switch for the turn signals. I still have no turn signals, but I think someone has previously messed around with the plug because the wires all come out of the plug very easily. I ran out of time before I could get any further on it due to having to pack up and head offshore for work. I am out here now doing some digging on here(and everywhere) and found that one of the wires going into the switch is in fact a brake on/off switch(LT GRN) and quite possibly the wires have been installed back into the plug incorrectly. I now have a correct diagram of the plug and which wire goes where. Hopefully this will fix my problem, or at least some of it. I do suspect there may be an issue with the PSOM as well. The LCD odometer is lit but pretty much unreadable, so I am thinking of replacing it anyway. Only other thing it could be would be the MLPS switch maybe. Anyone have any thoughts? Thanks!

 

does your speedo work(show speed), you can ohm your VSS by unplugging it and Ohm across the 2 pins should be 800-1400 Ohms

MLPS Ohm check

 

The speedo does work. I will ohm out the mlps when i get back from work and the VSS(i will probably go ahead and get a motorcraft vss as well. I am also going to pull the diff cover and inspect and change the fluid. Hopefully the tone ring will be good too.

 

Why would you ohm out the mlps for a 625 code?
625 code means the EPC solenoid did not change state.
Maybe bad wiring at the plug on the passenger side of the transmission.

The 452 says the VSS information is not getting to the PCM from the PSOM.

 

I am not getting the 625 anymore since I changed the solenoid block.

 

You may need to clean the turn signal switch to get it to work.

A dirty one:
Attachment 282120

A clean one:
Attachment 282121

Attachment 282122
Attachment 282123
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The VSS signal:
Attachment 277289
Attachment 280341

CHECK SPEEDOMETER SPEED OUTPUT SIGNAL.
Connect an AC voltmeter to Pin 7 (speed out) and Pin 2 (module ground). Does the voltage increase smoothly and continuously from 0 to approximately 4.5 volts as vehicle speed increases from 0 to approximately 30 mph?
OR,
If available, a frequency counter may be connected to Pin 7 (speed out) and Pin 2 (module ground). Does the displayed frequency of the signal increase smoothly and continuously from 0 to approximately 66.7 hz at approximately 30 mph?

CHECK SPEED INPUT SIGNAL
Connect an AC voltmeter to Pin 4 (speed +) and Pin 5 (speed -). Does the voltage increase smoothly and continuously from 0 to approximately 3.5 volts as vehicle speed increases from 0 to approximately 30 mph?
OR,
If available, a frequency counter may be connected to Pin 4 (speed in +) and Pin 5 (speed in -). Does the displayed frequency of the signal increase smoothly and continuously from 0 to approximately 666.7 hz at approximately 30 mph?

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Thanks for the pics. I will be going thru these when I get back home. Where did these come from? I would love to get a copy of this whole book or link.

 

Ok guys. Update. Found some of the wires crossed in the turn signal plug to the multifunction lever. Since I already bought a new one it is installed and I have turn signals! Woohoo! Also I am back to shifting while in drive, however still very firm up shifts 1-2 and downshifts. I did get a new plug kit for the solenoid pack on the trans because it was a little sketchy looking and wanted to eliminate that possibility. Installed it and still shifting hard. I also had a 332 code(egr) and knew that the vacuum line wasn’t hooked up. Before I knew how it was supposed to be routed I hooked it straight to the vacuum tree on the intake. I could hear the egr cycle(the egr is blocked off from the intake but is still installed. . I went for a spin. The trans shifted awesome. Nice and smooth, but the engine did not want to idle when slowing down to a stop. When I first crank it up it runs fine, put in gear, fine, when I tap the gas a little it will die. I have to keep my foot on the gas and brake at idle speeds to keep it running. I disconnect the vacuum line from the egr, it runs fine and shifts hard again. BTW I still have the 452 code. Didn’t have time to get to that today. Hoping to test the psom tomorrow