529 Data communication link or electronic engine controller fault

Make
Ford (1981-1995)
Category
Network Communications
Severity
Check Engine Light
Applies to
1981-1995 Ford, Lincoln and Mercury EEC-IV vehicles

How to read it

Code 529 reads as 5 flashes, pause, 2 flashes, pause, 9 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 529 mean?

529. Data communication link or electronic engine controller fault. This code sets when your vehicle computer detects data communication link or electronic engine controller fault.

Common causes of 529

How to fix 529

  1. Confirm the code and read the flash sequence again
  2. Inspect the data link wiring and module connectors
  3. Check the grounds at each module on the link
  4. Repair wiring or a bad ground before replacing a module
  5. Replace a failed module only after the link test fails