What causes Ford code 31?

The EGR valve position or pressure feedback circuit is shorted to ground. The EGR valve position sensor (EVP) or pressure feedback sensor failed and reads low. The EGR valve is stuck and does not move, so the position signal stays below minimum. The ECM reads the EGR feedback signal as low.

How do I fix Ford code 31?

Check the EGR position or pressure feedback circuit for a short to ground. Check the connector at the EGR position sensor for corrosion or a poor fit. Test the EGR valve and its position sensor and replace them only if they fail their own test. Test the ECM last, only after every circuit test has passed. Clear the code, then retest to confirm the feedback voltage rises into range.

Ford 31 EGR valve position or pressure feedback circuit below minimum voltage

Q: What does Ford code 31 mean?

Ford code 31. EGR valve position or pressure feedback circuit below minimum voltage.

Make: Ford (1981-1995)
Category: Powertrain - Auxiliary Emissions Controls
Severity: Check Engine Light

How to read it

Code 31 reads as 3 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 31 mean?

EGR valve position or pressure feedback circuit below minimum voltage

Common causes of 31

The EGR valve position or pressure feedback circuit is shorted to ground.
The EGR valve position sensor (EVP) or pressure feedback sensor failed and reads low.
The EGR valve is stuck and does not move, so the position signal stays below minimum.
The ECM reads the EGR feedback signal as low.

How to fix 31

Check the EGR position or pressure feedback circuit for a short to ground.
Check the connector at the EGR position sensor for corrosion or a poor fit.
Test the EGR valve and its position sensor and replace them only if they fail their own test.
Test the ECM last, only after every circuit test has passed.
Clear the code, then retest to confirm the feedback voltage rises into range.

Source

Source review recorded

Sources and review

Review: checked against the recorded source material.

EEC-IV Ford trouble code table (MIL, description, type)
archived reference page (troublecodes.net via Wayback Machine)
Supports: code identity and meaning
Fetched directly. Code 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 codes, Crown Victoria, Mustang, Taurus, Thunderbird 1992-1995 (code, fault location, probable cause)
archived reference page (troublecodes.net via Wayback Machine)
Supports: code identity and probable causes
Independent table on the same archive site with matching code identity and additional probable causes.
https://web.archive.org/web/20160502051413id_/http://www.troublecodes.net:80/ford/crown-victoria-mustang-cobralxgt-taurus-thunderbird-1992-1995/
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 31. Include your vehicle, the issue and a source if you have one.