Brand: YAMAHA
Category: Motorcycle
Document Type: Manual
Language: EN
Manual for YP250R/YP250RA
Uploaded: April 20, 2026, 8:14 p.m.
Manual Publish Date: 2013-11-01
This manual provides detailed information on the inspection, disassembly, assembly, checking, and adjustment of various components of the YP250R/YP250RA motorcycle. It covers general information, specifications, periodic maintenance, chassis components, engine, cooling system, fuel system, electrical system, and troubleshooting. The manual is intended for mechanics and service technicians, with step-by-step procedures, diagrams, and specifications to ensure proper maintenance and repair.
Troubleshooting and error codes
| Fault code No. | Item | Symptom | Maintenance job | Confirmation of service completion |
| 12 | Crankshaft position sensor | No normal signals are received from the crankshaft position sensor. | 1. Connection of crankshaft position sensor coupler. Check the locking condition of the coupler. Disconnect the coupler and check the pins (bent or broken terminals and locking condition of the pins). | Improperly connected → Connect the coupler securely or replace the wire harness. Crank the engine. Fault code number is not displayed → Service is finished. Fault code number is displayed → Go to item 2. |
| 13 | Intake air pressure sensor | Open or short circuit detected. | 1. Connection of intake air pressure sensor coupler. Check the locking condition of the coupler. Disconnect the coupler and check the pins (bent or broken terminals and locking condition of the pins). | Improperly connected → Connect the coupler securely or replace the wire harness. Turn the main switch to "ON". Fault code number is not displayed → Service is finished. Fault code number is displayed → Go to item 2. |
| 14 | Intake air pressure sensor | Hose system malfunction (clogged or detached hose). | 1. Condition of intake air pressure sensor hose. Check the intake air pressure sensor hose condition. Clogged or detached hose → Repair or replace the sensor hose. | Start the engine and let it idle for approximately 5 seconds. Fault code number is not displayed → Service is finished. Fault code number is displayed → Go to item 2. |
| 15 | Throttle position sensor | Open or short circuit detected. | 1. Connection of throttle position sensor coupler. Check the locking condition of the coupler. Disconnect the coupler and check the pins (bent or broken terminals and locking condition of the pins). | Improperly connected → Connect the coupler securely or replace the wire harness. Turn the main switch to "ON". Fault code number is not displayed → Service is finished. Fault code number is displayed → Go to item 2. |
| 16 | Throttle position sensor | Stuck throttle position sensor is detected. | 1. Installed condition of throttle position sensor. Check for looseness or pinching. | Improperly installed sensor → Reinstall. Refer to “THROTTLE BODY” on page 7-4. Turn the main switch to "ON" and then open and close the throttle valve. Fault code number is not displayed → Service is finished. Fault code number is displayed → Go to item 5. |
| 19 | Sidestand switch | A break or disconnection of the blue/yellow lead of the ECU is detected. | 1. Connection of sidestand switch coupler. Check the locking condition of the coupler. Disconnect the coupler and check the pins (bent or broken terminals and locking condition of the pins). | Improperly connected → Connect the coupler securely or replace the wire harness. Turn the main switch to "ON", and then extend and retract the sidestand. Fault code number is not displayed → Service is finished. Fault code number is displayed → Go to item 2. |
| 21 | Coolant temperature sensor | Open or short circuit detected. | 1. Connection of coolant temperature sensor coupler. Check the locking condition of the coupler. Disconnect the coupler and check the pins (bent or broken terminals and locking condition of the pins). | Improperly connected → Connect the coupler securely or replace the wire harness. Turn the main switch to "ON". Fault code number is not displayed → Service is finished. Fault code number is displayed → Go to item 2. |
| 22 | Intake air temperature sensor | Open or short circuit detected. | 1. Connection of intake air temperature sensor coupler. Check the locking condition of the coupler. Disconnect the coupler and check the pins (bent or broken terminals and locking condition of the pins). | Improperly connected → Connect the coupler securely or replace the wire harness. Turn the main switch to "ON". Fault code number is not displayed → Service is finished. Fault code number is displayed → Go to item 2. |
| 24 | O2 sensor | No normal signals are received from the O2 sensor. | 1. Installed condition of O2 sensor. Improperly installed sensor → Reinstall or replace the sensor. | Start the engine, warm it up, and then race it, or execute the diagnostic mode. (Code No. D63) Fault code number is not displayed → Service is finished. Fault code number is displayed → Go to item 2. |
| 30 | Latch up detected. | — | — | — |
| 33 | Ignition coil | Open or short circuit detected in the primary lead of the ignition coil. | 1. Connection of ignition coil coupler. Check the locking condition of the coupler. Disconnect the coupler and check the pins (bent or broken terminals and locking condition of the pins). | Improperly connected → Connect the coupler securely or replace the wire harness. Start the engine and let it idle for approximately 5 seconds. Fault code number is not displayed → Service is finished. Fault code number is displayed → Go to item 2. |
| 37 | Component other than ISC (idle speed control) unit is defective (ISC operating sound is heard). | — | — | — |
| 37 | Defective ISC (idle speed control) unit (ISC operating sound is not heard). | — | — | — |
| 39 | Injector | Open or short circuit detected. | 1. Connection of injector coupler. Check the locking condition of the coupler. Disconnect the coupler and check the pins (bent or broken terminals and locking condition of the pins). | Improperly connected → Connect the coupler securely or replace the wire harness. Execute the diagnostic mode. (Code No. D36) No operating sound → Go to item 2. Operating sound → Go to item 6. |
| 41 | Lean angle sensor | Open or short circuit detected. | 1. Connection of lean angle sensor coupler. Check the locking condition of the coupler. Disconnect the coupler and check the pins (bent or broken terminals and locking condition of the pins). | Improperly connected → Connect the coupler securely or replace the wire harness. Turn the main switch to "ON", then to "OFF", and then back to "ON". Fault code number is not displayed → Service is finished. Fault code number is displayed → Go to item 2. |
| 42 | (for YP250R) | Speed sensor: no normal signals are received from the speed sensor. | 1. Connection of speed sensor coupler. Check the locking condition of the coupler. Disconnect the coupler and check the pins (bent or broken terminals and locking condition of the pins). | Improperly connected → Connect the coupler securely or replace the wire harness. Turn the main switch to "ON" and then rotate the front wheel a few turns by hand. Fault code number is not displayed → Service is finished. Fault code number is displayed → Go to item 2. |
| 42 | (for YP250RA) | Front wheel sensor: no normal signals are received from the front wheel sensor. | 1. Connection of front wheel sensor coupler. Check the locking condition of the coupler. Disconnect the coupler and check the pins (bent or broken terminals and locking condition of the pins). | Improperly connected → Connect the coupler securely or replace the wire harness. Execute the diagnostic mode. (Code No. 07) Rotate the front wheel by hand and check that the indicated value increases. Value increases → Go to item 7 and delete the fault code. Value does not increase → Go to item 2. |
| 43 | Front wheel sensor | Missing pulses | 1. Foreign material adhered around the front wheel sensor | Check the surface of the sensor rotor and wheel sensor for foreign material, such as metal particles. Clean the sensor rotor and wheel sensor if necessary. |
| 44 | Rear wheel sensor | Missing pulses | 1. Foreign material adhered around the rear wheel sensor | Check the surface of the sensor rotor and wheel sensor for foreign material, such as metal particles. Clean the sensor rotor and wheel sensor if necessary. |
| 46 | Rear wheel sensor | Missing pulses | 1. Incorrect installation of the rear wheel | Check the components for looseness, distortion, and bends. Refer to “CHECKING THE REAR WHEEL” on page 4-29. |
| 47 | Rear wheel sensor | Missing pulses | 1. Defective sensor rotor or incorrect installation of the rotor | Check the surface of the sensor rotor for damage. Replace the sensor rotor if there is visible damage. Refer to “MAINTENANCE OF THE REAR WHEEL SENSOR ROTOR (for YP250RA)” on page 4-29. |
| 50 | ECU (engine control unit) | Malfunction in ECU. | Replace the ECU. | — |