PCM bad or good

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Dec 22, 2010 | 09:57 PM

my93

Thread Starter

Mountain Pass

Joined: Feb 2003

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PCM bad or good

Engine and trans has issues often and are intermittent at times.

I ran these test in the sequence below. What do you think, is the PCM good or bad?

Sequence of test for codes taken

(1) KOEO
111 - system passed

(2) Continuos codes
512 - PCM memory failure (ROM)

(3) KOER
311 - thermactor

Is the PCM bad due to code 512?

As I view the wiring diagram for the PCM it appears all wires that are red are neg. as one side of the load item is connected to red and otherside of the load is connected to pos.
Thanks

Dec 23, 2010 | 06:52 AM

Lazy K

Post Fiend

Joined: Jan 2005

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https://www.ford-trucks.com/forums/2...ode-512-a.html Have a read here, may help.
Hopefully other opinions to follow.

Dec 23, 2010 | 08:01 AM

my93

Thread Starter

Mountain Pass

Joined: Feb 2003

Posts: 184

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Read the thread and really does not say if that was his problem. He ordered a new one but never replied the outcome.
With the 512 code, does the computer loose the memory on a specific trouble? Or does it not know how to perform a solution with a code received.
Having the 512 code what effect would it have on the communication to the computer and the daily operation of the engine and auto trannie. Is this code only showing that it will either loose certain information and will not effect the operation of the PCM? Thanks

Dec 23, 2010 | 11:21 AM

rla2005

Fleet Owner

Joined: Oct 2005

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From: Kentucky

Code 512 only means the Keep Alive Memory test failed. This could be caused by momentarily removing power such as a fuse or battery cable, but not long enough to clear the codes. It does not necessarily indicate the PCM is bad. Pin 1 on the EEC connector is the power source for the Keep Alive Memory. Perhaps you have some corrosion on that pin? Does this code return after having cleared the codes previously?

Dec 23, 2010 | 12:29 PM

Kemicalburns

Hotshot

Joined: Jul 2002

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From: Bend,OR

do your battery cables and posts look good clean and tight.

Dec 23, 2010 | 03:52 PM

subford

Fleet Owner

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From: Easton,Ks

I always get the 512 code with my 95 Motorhome as it has a battery disconnect switch when I park it for awhile.
I also get it with my 95 150 if I unplug it to test another PCM Computer.

That is why you do not unhook the battery to clear codes as it will at least set this one.
You only disconnect the battery if you change a sensor (not a solenoid or relay). Then you will have to clear the codes after the battery is hooked back up.