Yamaha Immobilizer Code 55: Key Registration Malfunction — Fix
On Yamaha motorcycles and scooters with an immobilizer, code 55 means a malfunction occurred while registering key codes to the immobilizer — the registration process failed.
- Applies to
- Yamaha motorcycles
- Est. repair cost
- $20 – $300
- Time to fix
- 20–90 minutes
What it means
Usual causes are a registration procedure that went wrong, a faulty key transponder, or an immobilizer unit fault. Yamaha shows immobilizer faults as codes 51–55 on the same diagnostic display used for FI codes, on models fitted with the Yamaha Immobilizer (chip-key) anti-theft system. The engine will not start until the fault is resolved. Once the key/immobilizer fault is resolved the code clears; some faults (key or component registration) require a Yamaha diagnostic tool and the registration procedure.
Symptoms
- Key registration fails
- Code 55 shown
- Occurs during the key-programming procedure
How to fix it
- 1
Retry the registration correctly
1. Repeat the key registration using the correct Yamaha procedure with the master key and diagnostic tool. 2. Ensure no interference from other keys.
- 2
Replace a faulty key or unit
1. If registration keeps failing, test/replace the key transponder or the immobilizer unit, then re-register.
Frequently asked questions
Code 55 keeps appearing when programming a key — why?
The registration didn’t complete. Retry the exact procedure with the master key; if it still fails, the key transponder or immobilizer unit may be faulty.
Last updated July 16, 2026
Guidance only — always consult a qualified professional or the official service manual before carrying out repairs.