512 Keep alive memory test failure

Make
Ford (1981-1995)
Category
Powertrain - Computer and Auxiliary Controls
Severity
Check Engine Light
Applies to
1981-1995 Ford, Lincoln and Mercury EEC-IV vehicles

How to read it

Code 512 reads as 5 flashes, pause, 1 flash, pause, 2 flashes on the check-engine light. Jumper the self-test input to signal return at the test connector, then run the key on engine off self test and the running self test, counting the check-engine flashes each time.

New to flash codes? The OBD-I code reading guide walks through the paperclip method, code 12, and reading two-digit codes.

What does Ford code 512 mean?

512. Keep alive memory test failure. This code sets when your vehicle computer detects keep alive memory test failure.

Common causes of 512

How to fix 512

  1. Confirm the code and note whether battery power was recently interrupted
  2. Check the battery cables, grounds and the PCM memory fuse
  3. Measure battery and charging voltage under load
  4. Clear the code and retest before condemning the PCM
  5. Replace the PCM only if the memory test fails again with good power and grounds