FMI 14 — Special instructions
The manufacturer defines this one per SPN. You must read the OEM procedure for this exact code — there is no generic meaning.
Common causes
- OEM-specific condition tied to that SPN
- Aftertreatment or emissions routine outcome
- Security/anti-theft or configuration event
What to test, in order
- Pull the OEM troubleshooting tree for that SPN/FMI pair
- Check for related active and inactive codes for context
- Verify ECM calibration level
- Follow the OEM procedure exactly — generic circuit tests will not settle it
The reference is free. The diagnosis is Pro.
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