The Toyota P0451 code indicates a problem with the Evaporative Emission Control System Pressure Sensor range or performance. The code is triggered when the engine’s computer detects an abnormal pressure level within the evaporative emission control system. The code’s enabling conditions include an atmospheric pressure between 70 to 110 kPa-a (525 to 825 mmHg-a) [absolute pressure], a battery voltage of 10.5 V or higher, and an intake air temperature between 4.4 to 40°C (40 to 104°F). To maintain proper performance, all components of the EVAP system must be working in tandem with each other. If any part malfunctions, it can trigger the P0451 code. Common causes of this code include issues with the canister pump module, connector/wire harness, EVAP system hoses, and the ECM.
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Causes and Solutions for the Toyota P0451 Code
| Cause | Solution |
|---|---|
| Canister pump module | Replace the canister pump module |
| Connector/wire harness (Canister pump module – ECM) | Check the connections and replace the wire harness if necessary |
| EVAP system hose (pipe from the air inlet port to canister pump module, canister filter, fuel tank vent hose) | Replace any damaged hoses |
| ECM | Replace the ECM if necessary |