Ford 98 Hard fault present during self test

How to read it

Code 98 reads as 9 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.

What does Ford code 98 mean?

Hard fault present during self test

Common causes of 98

• A hard fault is present during the self test and does not clear on its own.
• The HO2S on bank 2 reads lean and sets the hard fault.
• The wiring or connector at the bank 2 HO2S is damaged or loose.
• The ECM sees the bank 2 HO2S signal as a hard lean fault.

How to fix 98

1. Scan the full code list because a hard fault can store more than one code.
2. Check the wiring and connector at the bank 2 HO2S.
3. Test the bank 2 HO2S and replace it only if it fails its own test.
4. Test the ECM last, only after every circuit test has passed.
5. Clear the code, then retest to confirm the hard fault is gone.

Source

Source review recorded