Yamaha FI Code 23: Atmospheric Pressure Sensor — Causes & Fix
On Yamaha motorcycles and scooters, FI fault code 23 means an open or short circuit was detected in the atmospheric (ambient) pressure sensor — used to compensate fueling for altitude and air pressure.
- Applies to
- Yamaha motorcycles
- Est. repair cost
- $20 – $120
- Time to fix
- 30–90 minutes
What it means
Common causes are a loose/corroded connector, damaged wiring, or a failed sensor (often built into the ECU or air-pressure module). 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 23 with warning light on
- Slight running or economy changes, especially with altitude
- Usually mild symptoms
How to fix it
- 1
Inspect connector and wiring
1. Reseat the sensor connector and check for corrosion. 2. Test the wiring for continuity.
- 2
Replace if faulty and reset
1. Replace the atmospheric pressure sensor/module if out of spec. 2. Clear the code.
Frequently asked questions
Will code 23 stop my bike?
Rarely — the ECU falls back to a default value, so the bike usually still runs. Fix it to keep fueling correct across altitudes.
Last updated July 15, 2026
Guidance only — always consult a qualified professional or the official service manual before carrying out repairs.