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Hi all, I think I already know the answer to my question but thought I'd confirm here. My 95 F250 (5.8/E4OD) started intermittently showing a check engine light, eventually becoming permanent. There are NO driveability issues, it runs the same as always. I pulled the codes (KOEO) and the only thing in there was a continuous memory code of 512 (power interrupt in the Keep Alive Memory (KAM) circuit). I cleaned the terminals and charged the battery without change. I pulled the PCM and verified that the terminals are clean and I have exact battery voltage across pins 1 and 60. I pulled the covers from the PCM but didn't see any burns or leaking caps. So I assume I'm down to a bad PCM itself? This unit is a Rock Auto rebuilt that I installed a little over 6 years ago. I'm surprised it's bad already but I am sort of at a loss to what else it could be.
So before I replace the PCM I'd love some confirmation that I'm on the right track. Thanks.
So yesterday I said I didn't see anything wrong with the board but today I took a closer look. Well guess what I found - a bunch of green crusties under the black component just under that big diode. No idea what it is, but I guess I'm going PCM shopping. Again.
I have never seen a Check Engine Light for Code 512. Typically that code is caused by pulling a battery cable to clear Stored Codes or other service work.
Clear the codes as instructed in the manual then drive the truck. If Code 512 returns then you may have a bad computer (PCM).
I have never seen a Check Engine Light for Code 512. Typically that code is caused by pulling a battery cable to clear Stored Codes or other service work.
Clear the codes as instructed in the manual then drive the truck. If Code 512 returns then you may have a bad computer (PCM).
Thanks, I neglected to mention that I did clear the codes and 512 came right back. It was the only stored code in the PCM.
If you have verified the Keep Alive Memory (KAM) is there at all times and you are still getting Code 512 then you are most likely looking at a bad computer.
Well good news/bad news. I went ahead and replaced the surface mount cap and repaired the broken trace on the circuit board and now the 512 code is gone. However, now I'm getting a 335 during self-test and 332 and 212 in continuous memory. I'm not 100% convinced that these are valid considering the damage to the circuit board. Then again, maybe these were my codes all along and the faulty trace/cap was keeping the PCM from storing them. Hmmm...
Code 332: EGR valve opening not detected. (CM and KOER)
Code 212: Loss of IDM input to EEC or SPOUT circuit grounded. (CM)
Typically Code 332 will trigger a Check Engine Light (CEL). Code 212...what color is the Ignition Control Module (ICM)? If it is gray or an aftermarket version they will trigger Code 212. Rarely will you get a CEL.
Well, I should have started with a visual inspection because when I looked into the EGR valve, I found this (doh!). Anyway, after I fixed it, all seems well. No CEL so far, and codes 332 and 335 are gone. So my theory is still the same - the bad capacitor and broken trace were the reason the PCM couldn't store the code, but the EGR was the real problem. I wonder if a KOER test would have revealed the EGR issue. Anyway it's fixed and I thank you for your help.
So one last question - code 212 remains but does not seem to set a CEL as you said. I think I do have the dreaded gray ICM (see last pic). I think I'll go ahead and replace it on principal.
