55 Key power check during self test
How to read it
Code 55 reads as 5 flashes, pause, 5 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 55 mean?
55. Key power check during self test. This code sets when your vehicle computer detects key power check during self test.
Common causes of 55
- Ignition switch not supplying power in the correct sequence
- Open or intermittent ignition switch circuit
- Low battery voltage during the test
- Corroded ignition switch connector
- PCM key power input fault
How to fix 55
- Confirm the code and repeat the self test with a fully charged battery
- Check the ignition switch and its connector for corrosion
- Measure PCM key power during the test
- Repair a poor connection before replacing the switch
- Retest once key power is steady