Yamaha FI Code 44: EEPROM (CO Adjustment) — Fix
On Yamaha motorcycles and scooters, FI fault code 44 means an error was detected reading or writing the ECU’s EEPROM — the memory that stores the CO/fuel-trim adjustment values.
- Applies to
- Yamaha motorcycles
- Est. repair cost
- $40 – $350
- Time to fix
- 30–90 minutes
What it means
This usually points to an internal ECU memory fault, though poor power/ground connections can contribute. This is a generic Yamaha fuel-injection (FI) fault code, so it applies across Yamaha FI models — scooters and underbones like the Mio, NMAX, Aerox, and Sniper, plus YZF-R and MT motorcycles. Yamaha shows the code as a number on the diagnostic/odometer display, and the engine-warning light comes on. Once the fault is repaired and the ECU no longer detects it, the code clears; cycling the ignition (or using a Yamaha diagnostic tool) may be needed to confirm.
Symptoms
- FI code 44 with warning light on
- Possible idle or fuelling irregularities
- Repeated or stuck code
How to fix it
- 1
Check ECU power and grounds
1. Inspect the ECU power and ground connections for corrosion or looseness. 2. Confirm battery/charging voltage is healthy.
- 2
Diagnose/replace the ECU
1. If power and grounds are good and the code persists, the ECU needs professional diagnosis or replacement. 2. Clear the code after repair.
Frequently asked questions
Does code 44 mean a new ECU?
Sometimes — but check the ECU’s power and grounds and the charging system first, since a poor supply can trigger it. If it persists, the ECU needs professional attention.
Last updated July 16, 2026
Guidance only — always consult a qualified professional or the official service manual before carrying out repairs.