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Every Weichai engine fault code in our verified reference — 45 codes, 13 of them with a documented remedy. Find your code in the table, read the likely causes, then work the remedy. If it is beyond a field fix, our workshop in Embakasi repairs Weichai controllers and engines at board level.
Covers: All Models · WP Series
| Code | Fault | Likely cause | Remedy |
|---|---|---|---|
| 111-18 | Engine coolant temperature high | The engine coolant temperature exceeds the safe limit; triggering a warning or shutdown. | — |
| 112-18 | Engine oil pressure low | The engine oil pressure is below the safe threshold; triggering a warning or shutdown. | — |
| 119 | Alternator overvoltage | The alternator output voltage exceeds the safe threshold; risking electrical damage. | — |
| 120 | Alternator undervoltage | The alternator output voltage is below the safe threshold; affecting power output. | — |
| 121 | Fuel pump failure | The fuel pump is not delivering fuel properly; affecting engine operation. | — |
| 122 | Engine overspeed | The engine speed exceeds 120% of nominal speed (e.g.; 1800 RPM for 60 Hz) | — |
| 123 | Engine underspeed | The engine speed is below the nominal threshold; affecting output frequency. | — |
| 124 | Air filter restriction | The air intake system is restricted; reducing engine performance. | — |
| 125 | ECU communication failure | The ECU has lost communication with the control panel or external devices.; opens; or loose connections. Verify the ECU is powered and operational. Check the control panel communication settings. Reset the fault via the ECU diagnostic tool and test communication. If the fault persists; consult the Weichai WP Series or a technician. | Inspect CAN bus or other communication wiring for shorts |
| 126 | Alternator phase imbalance | The alternator output shows an imbalance between phases; affecting power quality. | — |
| 127 | Engine shutdown solenoid failure | The shutdown solenoid is not functioning; affecting engine shutdown control. | — |
| 128 | Fuel solenoid valve failure | The fuel solenoid valve is not operating; affecting fuel delivery. | — |
| 129 | Engine preheating relay failure | The engine preheating relay (e.g.; for glow plugs) is malfunctioning | — |
| 130 | Alternator excitation failure | The alternator excitation circuit is not functioning; reducing output voltage. | — |
| 131 | Exhaust temperature high | The exhaust temperature exceeds the safe limit; indicating potential engine issues. | — |
| 131-3 | Accelerator pedal sensor 1 high voltage | The accelerator pedal position sensor 1 circuit voltage is above normal or shorted to high voltage. | Test accelerator pedal position sensor with multimeter for proper voltage (0–5V range); replace if defective. Inspect sensor wiring for shorts to power or damage. Check ECM harness for faults. Reset fault via ECU diagnostic tool and restart. |
| 132 | Engine oil temperature high | The engine oil temperature exceeds the safe limit; triggering a warning or shutdown. | — |
| 132-4 | Accelerator pedal sensor 1 low voltage | The accelerator pedal position sensor 1 circuit voltage is below normal or shorted to low voltage. | Test accelerator pedal position sensor with multimeter for proper voltage (0–5V range); replace if defective. Inspect sensor wiring for shorts to ground or opens. Check ECM harness for faults. Reset fault via ECU diagnostic tool and restart. |
| 133 | Turbocharger boost pressure sensor failure | The turbocharger boost pressure sensor is malfunctioning; affecting performance monitoring. | — |
| 134 | Engine crank failure | The engine failed to crank properly during a start attempt.; charge or replace if low. Inspect the starter motor and solenoid for faults | Check battery voltage (above 12.4V for 12V systems); test wiring for shorts or opens. Verify fuel supply and prime the system if needed. Test the crankshaft position sensor; replace if defective. Reset the fault via the ECU diagnostic tool and restart. Consult the Weichai WP Series or a technician if unresolved. |
| 135 | Control panel temperature high | The control panel temperature exceeds the safe limit; indicating overheating. | — |
| 135-3 | Fuel pressure sensor high voltage | The fuel pressure sensor circuit voltage is above normal or shorted to high voltage. | Test fuel pressure sensor with multimeter for proper resistance; replace if defective. Inspect sensor wiring for shorts to power or damage. Verify fuel system pressure ly if possible. Reset fault via ECU diagnostic tool and restart. |
| 136 | Alternator overcurrent | The alternator output current exceeds the safe limit; triggering a warning or shutdown. | — |
| 136-4 | Fuel pressure sensor low voltage | The fuel pressure sensor circuit voltage is below normal or shorted to low voltage. | Test fuel pressure sensor with multimeter for proper resistance; replace if defective. Inspect sensor wiring for shorts to ground or opens. Verify fuel system pressure ly if possible. Reset fault via ECU diagnostic tool and restart. |
| 137 | Engine cooling fan failure | The engine cooling fan is not operating; causing potential overheating. | — |
| 138 | Engine injector failure | One or more fuel injectors are malfunctioning; affecting combustion. | — |
| 139 | Alternator cooling fan failure | The alternator cooling fan is not operating; causing potential overheating. | — |
| 140 | Engine throttle actuator failure | The throttle actuator is malfunctioning; affecting engine speed control. | — |
| 141 | Fuel pump relay failure | The fuel pump relay is malfunctioning; affecting fuel delivery. | — |
| 141-3 | Manifold absolute pressure sensor high voltage | The MAP sensor circuit voltage is above normal or shorted to high voltage. | Test MAP sensor with multimeter for proper voltage and resistance; replace if defective. Inspect sensor wiring for shorts to power or damage. Check air intake system for blockages. Reset fault via ECU diagnostic tool and restart. |
| 142 | Control panel display failure | The control panel display is malfunctioning; preventing proper monitoring. | — |
| 142-4 | Manifold absolute pressure sensor low voltage | The MAP sensor circuit voltage is below normal or shorted to low voltage. | Test MAP sensor with multimeter for proper voltage and resistance; replace if defective. Inspect sensor wiring for shorts to ground or opens. Check air intake system for blockages. Reset fault via ECU diagnostic tool and restart. |
| 143 | Engine exhaust gas recirculation valve failure | The EGR valve is malfunctioning; affecting emissions and performance. | — |
| 144 | Alternator circuit breaker trip | The alternator circuit breaker has tripped due to overload or fault.; reduce if exceeding the generator’s capacity. Check alternator output cables for shorts or damage. Test the circuit breaker for proper operation | Inspect the electrical load; reset or replace if defective. Verify load connections for faults. Reset the fault via the ECU diagnostic tool and restart. to the Weichai WP Series or a technician if unresolved. |
| 145 | Control panel memory error | The control panel has detected a memory corruption or configuration error.; Power cycle the generator by disconnecting the battery for 30 seconds and reconnecting. Check for firmware updates for the control panel in the Weichai WP Series . Reset the control panel configuration to factory settings if possible. If the fault persists | replace the control panel. Reset the fault via the ECU diagnostic tool and restart. to the Weichai WP Series or a technician if unresolved. |
| 151-18 | Water in fuel detected | Water is detected in the fuel filter; risking engine damage. | — |
| 190-15 | Engine overspeed | The engine speed exceeds 120% of nominal speed (e.g.; 1800 RPM for 60 Hz) | — |
| 191-18 | Engine underspeed | The engine speed is below the nominal threshold; affecting output frequency. | — |
| 428-3 | Water in fuel sensor high voltage | The water-in-fuel sensor circuit voltage is above normal or shorted to high voltage. | Test water-in-fuel sensor with multimeter for proper resistance; replace if defective. Inspect sensor wiring for shorts to power or damage. Verify fuel filter condition. Reset fault via ECU diagnostic tool and restart. |
| 429-4 | Water in fuel sensor low voltage | The water-in-fuel sensor circuit voltage is below normal or shorted to low voltage. | Test water-in-fuel sensor with multimeter for proper resistance; replace if defective. Inspect sensor wiring for shorts to ground or opens. Verify fuel filter condition. Reset fault via ECU diagnostic tool and restart. |
| 651-3 | Injector 1 circuit fault | The injector 1 circuit is malfunctioning; affecting fuel delivery. | — |
| 652-3 | Injector 2 circuit fault | The injector 2 circuit is malfunctioning; affecting fuel delivery. | — |
| 653-3 | Injector 3 circuit fault | The injector 3 circuit is malfunctioning; affecting fuel delivery. | — |
| 654-3 | Injector 4 circuit fault | The injector 4 circuit is malfunctioning; affecting fuel delivery. | — |
| 1103-3 | Intake air temperature sensor high voltage | The intake air temperature sensor circuit voltage is above normal or shorted to high voltage. | Test intake air temperature sensor with multimeter for proper resistance; replace if defective. Inspect sensor wiring for shorts to power or damage. Verify air intake system condition. Reset fault via ECU diagnostic tool and restart. |
Codes and descriptions are industry-standard identifiers reproduced for identification only. This reference is not affiliated with or endorsed by Weichai; for official procedures always refer to the manufacturer’s service manual for your specific engine. A dash means our registry holds no verified entry for that column — we publish the gap rather than fill it in.
Send us the code and the engine serial. We diagnose Weichai sets on site across all 47 counties, and repair controllers at board level on the bench in Embakasi.