28 Loss of ignition diagnostic module signal on the right bank
How to read it
Code 28 reads as 2 flashes, pause, 8 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 28 mean?
28. Loss of ignition diagnostic module signal on the right bank. This code sets when your vehicle computer detects loss of ignition diagnostic module signal on the right bank.
Common causes of 28
- Faulty ignition coil or ignition control module
- Open or shorted ignition diagnostic wiring
- Faulty vane air temperature sensor on some models
- Corroded ignition wiring connector
- PCM input fault
How to fix 28
- Confirm the code and identify the affected ignition bank
- Inspect the coil and module connectors and the diagnostic wiring
- Test the diagnostic signal from the coil or module
- Repair wiring before replacing the coil or module
- Replace the failed component only after the signal test fails