Ford 651 Electronic pressure control circuit failure
How to read it
Code 651 reads as 6 flashes, pause, 5 flashes, pause, 1 flash 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 How to Read Ford EEC-IV Self-Test Codes walks through the test and what the numbers mean. The general OBD-I guide covers the rest.
What does Ford code 651 mean?
Electronic pressure control circuit failure
Common causes of 651
- An EPC solenoid that fails the KOEO circuit check
- An open or short in the EPC solenoid harness
- A failed electronic pressure control solenoid
- An internal fault in the PCM EPC output
How to fix 651
- Run the KOEO test and confirm the EPC circuit fault
- Check the EPC solenoid harness for an open or short
- Test the EPC solenoid and replace it only if it fails its own test
- Test the PCM last, only after every circuit test has passed
- Clear the code, then retest to confirm the fix holds
Source
Qualified source review
Sources and review
Review: qualified. Read the source limits below.
- EEC-IV Ford trouble code table (MIL, description, type)
archived reference page (troublecodes.net via Wayback Machine)
Supports: code identity and meaning
Fetched directly. The three-digit row matches the description used in the data file.
https://web.archive.org/web/20030720231430id_/http://www.troublecodes.net:80/Ford/eec-iv.shtml
- Ford EEC-IV trouble code table: code, fault location, probable cause (Crown Victoria, Mustang, Taurus, Thunderbird 1992-1995)
reference page (troublecodes.net)
Supports: per-code probable causes used for the page cause list and test order
Fetched 2026-09-30. The probable cause column is what the page lists, in source order, with the test order built from it.
https://www.troublecodes.net/ford/crown-victoria-mustang-cobralxgt-taurus-thunderbird-1992-1995/
Last updated 2026-10-10.
Report a correction for 651. Include your vehicle, the issue and a source if you have one.