Yamaha YBR 125 Owner Blog : Yamaha YBR 125 Diagnostic Fault codes

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Always ensure the bike is in neutral and on its center stand before turning the ignition on for diagnostics. Never attempt to read codes while the engine is running at high speed or while riding, as this can lead to an accident or mechanical failure.

Fault codes can be read on the dashboard but the Yamahas FI diagnostics machine is excellent to own and includes bi directional control for diagnostics see if your lucky and there is one on

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Fault codes are stored on the ECU , these will be shown via the engine fault light on the dash board
as a series of flashes of the light .

The engine management light will come on for 3 secs every time you start the bike , if the light does not come on replace the bulb at rear of clocks .

Codes are all 2 digit numbers , the first number will be read by long flashes of the light , the second number of the code with be in short flashes of the light .

Yamaha YBR 125 Diagnostic Fault Codes: The Complete Guide

If your engine management light (orange/amber) is flashing while the engine is off or idling, your ECU is trying to tell you exactly what is wrong. You do not need a scanner to read these—just your eyes and this guide.

How to Read the Flashes

The light uses "Long" and "Short" flashes to give you a 2-digit code:

Long Flash (1.5 sec): The first digit (Tens).
Short Flash (0.5 sec): The second digit (Units).
Example: 2 Long + 8 Short = Code 28 (Engine Temp Sensor).

Fault Code Master Table

Code	Component / System	Common Symptoms
12	Crankshaft Position Sensor	Bike won’t start; no spark.
13	Intake Air Pressure (Open/Short)	Rough idling or stalling.
14	Intake Air Pressure (Pipe Clog)	Poor throttle response.
15	Throttle Position Sensor (TPS)	Flat spots or "hesitation" when accelerating.
19	Sidestand Switch / Ignition	Bike cuts out when put into gear.
22	Intake Air Temp Sensor	Hard to start in cold weather.
28	Engine Temp Sensor	Overheating or poor fuel economy.
30	Lean Angle (Tip Over) Sensor	Bike won't start after being dropped.
33	Ignition Coil	Misfiring or intermittent cutting out.
39	Fuel Injector	Smelling fuel or no fuel reaching engine.
41	Tip Over Sensor (Voltage)	ECU detects a tilt sensor wiring fault.
42	Speed Sensor / Neutral Switch	Speedometer issues or neutral light flickering.
44	ECU EEPROM Error	Bike may not run; internal ECU memory fault.
46	FI System Power Supply	Battery voltage is too low or charging system failed.
50	ECU Internal Fault	Hardware failure (rare).

Fault code 51 - Diagnosis cooling fan motor relay

Fault code 52 - relay diagnostics lamp head light

3-Step Fix Action Plan

Check the Connection: 90% of YBR electrical faults are just dirty or loose plugs. Unplug the sensor, spray with Contact Cleaner, and reconnect.
Inspect the Loom: Look for wires that have rubbed against the frame (especially near the headstock).
The "Hard Reset": If you’ve fixed the part but the light stays on, disconnect the negative battery terminal for 15 minutes to clear the ECU's temporary memory.

Yamaha YBR 125 how to read a fault code