B1647 The keyless access unit saw a short in the passenger door low frequency antenna circuit
What does B1647 mean on a Honda?
B1647. The keyless access unit saw a short in the passenger door low frequency antenna circuit. The smart key may not be detected at the passenger door. This Honda-enhanced code applies to Honda and Acura models that use this code.
Common causes of B1647
- Faulty passenger door low frequency antenna
- Passenger door low frequency antenna harness is open or shorted
- Passenger door low frequency antenna circuit poor electrical connection
- Faulty keyless access control unit
- Corroded or loose connector pins at the antenna
How to fix B1647
- Confirm the code with a scan tool and check the smart key at that location
- Inspect the antenna connector and wiring for corrosion, moisture, and loose pins
- Test the antenna circuit for an open or short with a multimeter
- Check the wiring before replacing the antenna
- Replace the passenger door low frequency antenna if it fails testing, then clear codes and retest
Sources and review
- Last updated 2026-09-29.