456 Insufficient engine speed decrease during the cruise control KOER test
How to read it
Code 456 reads as 4 flashes, pause, 5 flashes, pause, 6 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 456 mean?
456. Insufficient engine speed decrease during the cruise control KOER test. This code sets when your vehicle computer detects insufficient engine speed decrease during the cruise control koer test.
Common causes of 456
- Faulty cruise control servo or vacuum hose
- Faulty cruise control switch
- Open or shorted wiring in the cruise control circuit
- Corroded or loose connector in the cruise control circuit
- Faulty PCM cruise control input
How to fix 456
- Confirm the code and check the cruise control operation
- Inspect the cruise control servo and vacuum hoses
- Test the cruise control switch and circuit
- Repair wiring or a hose before replacing parts
- Replace a failed part only after the tests