Yamaha motorcycle fault codes and warning indicators, with meanings, causes, and step-by-step fixes.
91 models · 28 error codes
On Yamaha motorcycles and scooters, FI fault code 12 means the ECU is getting no signal from the crankshaft position sensor — the sensor that tells the ECU engine speed and position for spark and injection timing.
On Yamaha motorcycles and scooters, FI fault code 13 means an open or short circuit was detected in the intake air pressure (MAP) sensor — the sensor that reads manifold pressure so the ECU can set fueling.
On Yamaha motorcycles and scooters, FI fault code 15 means an open or short circuit was detected in the throttle position sensor (TPS) — the sensor that reports how far the throttle is open.
On Yamaha motorcycles and scooters, FI fault code 21 means a fault was detected in the coolant temperature sensor circuit — the sensor the ECU uses for cold-start enrichment and fan control.
On Yamaha motorcycles and scooters, FI fault code 22 means an open or short circuit was detected in the intake air temperature sensor — used to fine-tune fueling for air density.
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.
On Yamaha motorcycles and scooters, FI fault code 24 means the O2 (oxygen) sensor is inactive or sending no normal signal — the sensor the ECU uses to trim the mixture for clean, efficient running.
On Yamaha motorcycles and scooters, FI fault code 30 means the ECU has registered that the motorcycle overturned — the lean-angle (tip-over) sensor has cut the engine as a safety measure.
On Yamaha motorcycles and scooters, FI fault code 46 means a power-supply fault to the fuel-injection system was detected — the FI system isn’t getting correct voltage (often a charging or wiring problem).
On Yamaha motorcycles and scooters, FI fault code 50 means the ECU has detected an internal memory (fault-code memory) error — a problem inside the engine control unit itself.
On Yamaha motorcycles and scooters, FI fault code 33 means an open circuit was detected in the primary lead of the No. 1 ignition coil — the coil that fires that cylinder’s spark plug.
On Yamaha motorcycles and scooters, FI fault code 39 means an open circuit was detected in a fuel injector — the ECU isn’t driving the injector correctly.
On Yamaha motorcycles and scooters, FI fault code 41 means an open or short circuit was detected in the lean-angle sensor — the safety sensor that cuts the engine if the bike leans too far or falls. (This is the sensor-circuit fault; code 30 is the actual overturn event.)
On Yamaha motorcycles and scooters, FI fault code 42 means no normal signal is being received from the speed sensor — the sensor that reports road speed to the ECU and speedometer.
On Yamaha motorcycles and scooters, FI fault code 43 means the power supply to the injectors and fuel pump is not normal — the FI system isn’t getting correct voltage (often a charging or wiring fault).
On Yamaha motorcycles and scooters, FI fault code 11 means no normal signal is being received from the cylinder-identification sensor — the sensor the ECU uses to know which cylinder is on its firing stroke.
On Yamaha motorcycles and scooters, FI fault code 14 means a hose fault on the intake air pressure sensor — the vacuum hose is clogged, kinked, or detached (this is the hose problem; code 13 is the sensor’s electrical circuit).
On Yamaha motorcycles and scooters, FI fault code 17 means an open or short circuit in the EXUP servo-motor circuit. EXUP is Yamaha’s exhaust valve (fitted to sport models such as the R1, R6, MT-09) that boosts mid-range power.
On Yamaha motorcycles and scooters, FI fault code 18 means the EXUP servo motor is stuck — it isn’t moving the exhaust valve through its expected range (on models fitted with EXUP).
On Yamaha motorcycles and scooters, FI fault code 19 means an open circuit was detected in the input lead from the sidestand switch to the ECU — the switch that cuts the engine if you ride off with the stand down.
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.
On Yamaha motorcycles and scooters with an immobilizer, code 51 means the immobilizer unit cannot receive a code from the key — it isn’t picking up the transponder chip in the key.
On Yamaha motorcycles and scooters with an immobilizer, code 52 means the code read from the key does not match the code stored in the immobilizer — usually an unregistered or wrong key.
On Yamaha motorcycles and scooters with an immobilizer, code 53 means codes cannot be transmitted between the ECU and the immobilizer unit — a communication failure between the two.
On Yamaha motorcycles and scooters with an immobilizer, code 54 means the codes exchanged between the ECU and the immobilizer unit do not match — the two are no longer paired.
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.
On Yamaha motorcycles and scooters, FI fault code 16 means the throttle position sensor is stuck/jammed — its signal isn’t tracking the throttle properly (this is the "stuck" fault; code 15 is the electrical open/short).
On Yamaha motorcycles and scooters, FI fault code 37 means a fault in the idle-speed control system — the fast-idle/ISC valve isn’t controlling idle correctly (often stuck open, giving a high idle after warm-up).
These codes apply across Yamaha models, including:
