Suzuki FI Code C44: O2 Sensor — Causes & Fix
On Suzuki motorcycles and scooters, FI code C44 means a fault in the heated oxygen (O2) sensor circuit — the sensor the ECM uses to trim the mixture for clean, efficient running.
- Applies to
- Suzuki motorcycles
- Est. repair cost
- $25 – $160
- Time to fix
- 30–90 minutes
What it means
Typical causes are a loose/corroded connector, an exhaust leak before the sensor, harness damage, or an aged/failed O2 sensor. This is a generic Suzuki fuel-injection (FI) code, so it applies across Suzuki FI models — the Raider R150 Fi, Smash, Gixxer, GSX-R and GSX-S range, V-Strom, and more. Suzuki reports it as a "C" number, shown through the FI-light blink pattern or by entering the bike’s dealer/diagnostic mode. After the fault is repaired it becomes a stored "history" code; clear it through Suzuki’s dealer/diagnostic mode so the FI light goes out.
Symptoms
- FI light on with code C44
- Worse fuel economy
- Mild running roughness; may fail emissions
How to fix it
- 1
Inspect the connector and exhaust
1. Find the O2 sensor in the exhaust header. 2. Reseat the connector; check for exhaust leaks upstream that skew the reading.
- 2
Test and replace
1. Check the sensor and its heater circuit. 2. Replace an aged or dead sensor, then clear the code.
Frequently asked questions
Can I ride with C44?
Usually yes for a while — the ECM uses a preset map — but economy drops. Replace the sensor when convenient.
Last updated July 15, 2026
Guidance only — always consult a qualified professional or the official service manual before carrying out repairs.