Keep Alive Memory Test Failure
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5 Year Member
Joined: Feb 2012
Posts: 148
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Keep Alive Memory Test Failure
I have a 1993 F-150 Lightning and when I run the error codes via the KOEO Test, I get a code 512 - Keep Alive Memory Test Failure. When started (cold engine), it often hunts for idle and then after warming up, the engine runs fine. The only other symptom I have is that the gas mileage is definitely off from what it has been. Have checked Idle air Control and also replaced Intake Air Temp Sensor & engine Coolant Sensor. Has anyone had similar problems or an idea?
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Joined: Feb 2011
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From: Superior, WI
I would suspect either a very marginal battery - one that is dropping below the voltage necessary to keep the Keep-alive memory alive when you are cranking the engine
or -
you could have a bad PCM that isn't keeping the memory when the key is turned off
I don't think there would be a seperate power run for the KAM, since the computer needs voltage all the time.
The other symptoms you describe are all caused by the PCM losing its memory of what it had to do the last time you drove.
Note that the "Test failure" most likely means that the PCM has failed and you will need to replace it.
or -
you could have a bad PCM that isn't keeping the memory when the key is turned off
I don't think there would be a seperate power run for the KAM, since the computer needs voltage all the time.
The other symptoms you describe are all caused by the PCM losing its memory of what it had to do the last time you drove.
Note that the "Test failure" most likely means that the PCM has failed and you will need to replace it.
Last edited by p38fln; Feb 23, 2012 at 06:06 PM.
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Last edited by AutoAnything; Feb 24, 2012 at 12:21 PM.
Thread Starter
5 Year Member
Joined: Feb 2012
Posts: 148
Likes: 33
I would suspect either a very marginal battery - one that is dropping below the voltage necessary to keep the Keep-alive memory alive when you are cranking the engine
or -
you could have a bad PCM that isn't keeping the memory when the key is turned off
I don't think there would be a seperate power run for the KAM, since the computer needs voltage all the time.
The other symptoms you describe are all caused by the PCM losing its memory of what it had to do the last time you drove.
Note that the "Test failure" most likely means that the PCM has failed and you will need to replace it.
or -
you could have a bad PCM that isn't keeping the memory when the key is turned off
I don't think there would be a seperate power run for the KAM, since the computer needs voltage all the time.
The other symptoms you describe are all caused by the PCM losing its memory of what it had to do the last time you drove.
Note that the "Test failure" most likely means that the PCM has failed and you will need to replace it.
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Thread Starter
5 Year Member
Joined: Feb 2012
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Follow-up on my KAM Failure. Finally got a chance today to pull the harness away from the PCM and check for power. As I understand it, Pin #1 (Yellow wire) in the power supply for the KAM circuit and Pin #60 is the ground. Checked Pin #1 to Pin #60 and got the same voltage I get across the battery terminals (12.58 volts). Also checked Pin #1 to other ground and got the same voltage. Additionally, had the battery load tested and it checks out very well.
I'm thinking that the PCM is failing. any other thoughts?
I'm thinking that the PCM is failing. any other thoughts?
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Joined: Apr 2018
Posts: 10
Likes: 1
From: San Angelo, TX
What'd you find out?
Follow-up on my KAM Failure. Finally got a chance today to pull the harness away from the PCM and check for power. As I understand it, Pin #1 (Yellow wire) in the power supply for the KAM circuit and Pin #60 is the ground. Checked Pin #1 to Pin #60 and got the same voltage I get across the battery terminals (12.58 volts). Also checked Pin #1 to other ground and got the same voltage. Additionally, had the battery load tested and it checks out very well.
I'm thinking that the PCM is failing. any other thoughts?
I'm thinking that the PCM is failing. any other thoughts?