The body control module sees a fault in the license plate light circuit
What it means
B109B. The body control module sees a fault in the license plate light circuit. The plate light may not come on or the lamp out warning may show.
Findings, check these first
- Faulty license plate light bulb
- Open or shorted license plate light wiring
- Poor ground or connector at the lamp
- Corroded license plate light socket
- Faulty body control module output
Standard procedure
- Confirm the code and check the license plate light
- Inspect the bulb, socket and connector
- Test the license plate light circuit for an open or short
- Check the ground at the lamp housing
- Repair the wiring or replace the failed part after tests
Code lookup
Type a code above, or start from a symptom or a common code.
Press / to jump to the box. Ford-enhanced powertrain, body, chassis and network codes. Generic P0xxx codes live on OBD Codes List.
Sources and review
Review: checked against the recorded source material.
- B109B FORD: Code Meaning, Causes, Symptoms, & Tech Notes | Engine-Codes.com
archived reference page (engine-codes.com via Wayback Machine)
Supports: code identity, Ford meaning and possible causes
Fetched directly. Ford title, meaning and causes match the catalog record. Model and year fitment remain curator claims.
- B109B FORD License Plate Light | AutoCodes.com
archived reference page (autocodes.com via Wayback Machine)
Supports: corroboration of Ford meaning and causes
Same Ford text as the engine-codes page (both sites share one publisher).
Last updated 2026-09-26.
Report a correction for B109B. Include your vehicle, the issue and a source if you have one.