Hey ford gurus i need some held when i do the self test im getting code 558 so i started to diagnose this and tested the evr and it came up good with 38 ohms then checked the volts to the solenoid and i had 12vdc on one side and 10vdc on the other. From what i have read one side should be grounded from the pcm correct and not have 10 volts to it? I went and ohm the wires from the connector to the pcm connector and make sure they were good and also checked them againt all the other pins on the pcm connector to see if the was a short and their was not so im out of ideas can someone help me?

 

The PCM only grounds that wire with a warm engine that is not at idle or WOT.

DTC 558 indicates a failure in the EGR Vacuum Regulator (EVR) solenoid circuit.
Possible causes:
-- Damaged EVR solenoid.
-- Open harness.
-- Shorted harness.
-- Damaged Powertrain Control Module (PCM).

 

When i tested and got the 10 volts it was while doing the self test whith thee eec connector jumped to the sti so i thought it would ground it then

 

Well it does have a 2volt drop across the solenoid so it is grounding it some.

 

This was with it disconnected and one lead on the terminal and one on the negitive battery terminal

 

The PCM pulses the EVR solenoid very rapidly, so on the ground side you might see anything from 12 volts to 0 volts depending on how open the PCM wants the EGR valve.

 

Im out of ideas then what should i check next?

 

If the EVR solenoid has power, and the wire going from the EVR to the PCM has 0 resistance, I would suspect a bad PCM.

Do you have any other vehicles you could try swapping an EVR or PCM from?

 

No i dont have anything to swap from unfoutunantly and i have swaped the evr and no dice i have been suspecting pcm but nothing else is wrong like fuel pump staying on and everything else is working except the torque converter im getting 626 and 629 also all the wires are good and ohmed out so i have need to replace the solenoid pack

 

626 & 629 are two different solenoids that did not change state so I dough that the solenoid pack is bad along with the EVR code.

I think you have a bad computer so pull it out and open it up and check out the lectrolytic capacitors. I think you will find them bad, I did in my 1993 and replaced all three of them.

 

I did open it up and did not see them visually bad but that dosent mean any thing. So you think the pcm might ve my problem with all 3 codes?

 

It is a good possibility.
I would go to a salvage yard and get one for a test for about $30.00.
Just get one about your year (1992-1993) that came from a truck with a the same transmission (E4OD?) and engine size.
Even if the one you get is bad in some way if it does not give you the same codes then you know your other computer was bad.

 

Alright will do but finding one is the harder part i looked this past friday at pick and pull and all that was their was 5.0 in my year range mine is a 93 5.8 with e4od 4x4. Sorry should have posted that earlier. But since capacitors are cheap and i can soder maybe i should just switch them out while im trying to find a second pcm. Do you think thats a good idea? Thanks and subford i have been a long term lurker and you posts and many others of this great fourm have pretty much got me to get this truck running. It sat for 5 years befor i inherited it

 

You can try changing the capacitors out, just get low-ESR capacitors from top-brands like Panasonic, Rubycon or Nippon-Chemi-Con that match the specs of your existing ones.

A 5.0 PCM will run your engine, but no perfectly.

 

If the 5.0L you speak of had a E4OD its computer would be a good test for those codes you got.

Not sure I would replace the electrolytic capacitors if they did not showed any sign of leaking, broken loose or bulging. There was no dough with my 1993 460 E4OD 4X4, as they were leaking.

Here is the ones I bough:


/