Code 558
04-16-2018, 10:12 PM
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Code 558
Hello! This is my first post after being an active reader on this forum for months. Let’s cut to the chase- getting code 558 on my 93 F150 4.9L with the in-line 6. It has been a wild goose chase ever since I bought the truck a few months ago, but so far I have had all the vacuume lines redone, installed a new EGR solenoid, installed a new PCM after opening it and seeing a few Capicitors rusted through. I have checked the “coffee can” for vacuum, as well as the EGR valve, which also holds a vac. I’m out of ideas, i was almost certain the new pcm would solve the problem but the CEL came back on. Something to note, it only comes on and throws the code when the engine is warmed up, so not sure if that offers any insight. Any help or suggestions would be welcomed!
Thanks,
Spencer
Thanks,
Spencer
04-16-2018, 11:12 PM
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We don't have all the code definitions memorized. When you post a number, include its COMPLETE definition. The caption of this diagram contains the definitions specific to these trucks:
(phone app link)
The first step in diagnosing any code is to confirm that the indicated condition exists.
(phone app link)
The first step in diagnosing any code is to confirm that the indicated condition exists.
04-17-2018, 11:26 AM
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So is there anything wrong with the EVR circuit on your truck?
(phone app link)
(phone app link)
(phone app link)
(phone app link)
(phone app link)
(phone app link)
04-18-2018, 11:27 AM
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Before you can check a specific circuit, you have to understand how it works to know what you're checking for, how to check it, and what the results mean.
But you can check virtually any circuit (wire) by disconnecting ALL its terminals (connectors) so it's just a wire, and then checking for continuity (<0.5 Ohms resistance from any point on that wire to every other point on the same wire) and shorts to other wires (high~infinite resistance from the target wire to every other wire in that harness, and to body ground).
The EVR works almost like a light bulb - it gets B+ (12~14V) on the Red wire all the time (key ON), and the EEC pulses the EVR wire to ground to modulate the EVR (turn it on & off rapidly as needed). It's also the way the other vacuum solenoids, fuel injectors, HEGO heater, and some other things work. The fault code says there's something wrong with the EVR wire; not the B+ wire (VPWR). So measuring voltage probably won't be useful. I expect you'll find the problem with the basic circuit tests (continuity & short).
But you can check virtually any circuit (wire) by disconnecting ALL its terminals (connectors) so it's just a wire, and then checking for continuity (<0.5 Ohms resistance from any point on that wire to every other point on the same wire) and shorts to other wires (high~infinite resistance from the target wire to every other wire in that harness, and to body ground).
The EVR works almost like a light bulb - it gets B+ (12~14V) on the Red wire all the time (key ON), and the EEC pulses the EVR wire to ground to modulate the EVR (turn it on & off rapidly as needed). It's also the way the other vacuum solenoids, fuel injectors, HEGO heater, and some other things work. The fault code says there's something wrong with the EVR wire; not the B+ wire (VPWR). So measuring voltage probably won't be useful. I expect you'll find the problem with the basic circuit tests (continuity & short).
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04-19-2018, 09:09 PM
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Success!
Success! Oh sweet sweet success! All of those sleepless nights, mind-wandering days and self doubt have been relinquished. Checked the circuit and realized that the EGR solenoid wasn't operating, it was shot, even though I replaced it recently. Then I remembered that the computer was shot also, so I am thinking that even though the solenoid was replaced, the new one must had fried due to the fact that the ECM has some rusted out transistors- so maybe, just maybe, that sent an irregular voltage to the solenoid. Anyways, swapped out the solenoid, after installing a new ECM, and all seems fine. Got it smogged and registered today, and all is well! Thanks for all your help, got me through it!
04-19-2018, 09:27 PM
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I'm glad it's fixed, and that you found a bad part.
But the EEC doesn't really send voltage to the EVR. The EEC PWR relay sends battery voltage to the EVR & several other things. The EEC just grounds the EVR wire to pulse it on/open, but the EVR can tolerate constant battery voltage (full current) for hours (probably years) without damage. Did the newest EVR pass all the tests that the previous one failed?
But the EEC doesn't really send voltage to the EVR. The EEC PWR relay sends battery voltage to the EVR & several other things. The EEC just grounds the EVR wire to pulse it on/open, but the EVR can tolerate constant battery voltage (full current) for hours (probably years) without damage. Did the newest EVR pass all the tests that the previous one failed?