Which Codes Will This Page Cover?
- P0451 Evaporative Emission System Pressure Sensor/Switch
- P0452 Evaporative Emission System Pressure Sensor/Switch Low
- P0453 Evaporative Emission System Pressure Sensor/Switch High
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What Is the P0451 Code?
Symptoms
Causes
Seriousness
Can I Still Drive?
Diagnose
Difficulty of Inspecting
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A P0451 code is an OBD-II fault code defined as “Evaporative Emission System Pressure Sensor/Switch.” This code is triggered when the vehicle’s Powertrain Control Module (PCM) detects an inaccurate or erratic voltage signal from the Evaporative Emission Control System Pressure Sensor.
A vehicle’s fuel gradually evaporates over time while in the fuel storage system. To combat this, a vehicle’s Evaporative Emission Control System (EVAP) stores and purges the evaporated fuel back into the engine’s combustion process. When the EVAP sensor detects pressure changes outside the accepted manufacturer range, it triggers the P0451 code.
The P0451 code triggers for a variety of reasons, so it’s crucial to have a qualified technician diagnose the specific cause for this code.
What Are the Symptoms of a P0451 Code?
If your vehicle encounters a P0451 code issue, your vehicle may not experience any serious symptoms. In most cases, the only noticeable symptom will be that your vehicle will display a Check Engine Light on the dashboard. However, aside from the Check Engine Light displaying on your dashboard, you may also notice an unpleasant smell of gasoline coming from the engine caused by the release of fuel vapors.
What Are Some Causes of a P0451 Code?
There are a variety of causes. Common ones include a faulty fuel tank, a faulty fuel tank sending unit or pressure sensor, or an open or shorted fuel tank pressure sensor circuit.
How Serious Is the P0451 Code?
The P0451 code issue is among the least severe OBD-II codes. Often, the only noticeable symptom is the illumination of the Check Engine Light on your vehicle’s dashboard. However, despite no severe symptoms present, your vehicle may emit harmful and unpleasant gasoline vapors and odors. Therefore, a qualified technician should take a look at your car and address this issue for health safety reasons.
Can I Still Drive with a P0451 Code?
A P0451 code often has no impact on vehicle performance or driveability, but the code may sometimes appear alongside other more serious OBD-II codes. Therefore, if you’re experiencing a Check Engine Light illuminating on your dashboard or notice any unpleasant gasoline odors, it’s strongly recommended to get your vehicle inspected as soon as possible.
How Easy Is It to Diagnose a P0451 Code?
Diagnosing a P0451 code issue correctly is not always an easy process. As a result, most people leave it to the professionals and take their vehicle in for a check-up.
Most technicians first identify codes stored by the vehicle’s PCM by utilizing an OBD-II scanner. They then take note of all the codes presented and start addressing each code in the order in which the PCM stored it. Often, when a P0451 code is initially triggered, other related OBD-II codes will be triggered and stored shortly after.
After performing the scan, the technicians will visually inspect the vehicle and related sensors and modules.
How Difficult Is It to Inspect a P0451 Code?
Correctly inspecting and diagnosing a P0451 code involves taking a multi-step diagnostic approach, which is why a DIY diagnosis is not recommended. Instead, it’s best to let qualified technicians with experience diagnose the issue.
The first thing a technician will then do after scanning and identifying the code will be to visually inspect for any damaged or faulty wiring, connections, and circuits. After the technician identifies and repairs any faulty wiring, connectors, or circuits, they will clear the P0451 code and retest the system.
If all is deemed OK by the technician, they will then proceed to inspect the charcoal canister, the purge valve, the vacuum and vapor hoses, and all other Evaporative Emission Control System-related components. They will inspect and repair each component as necessary and then clear the codes and retest the engine until the code issue is resolved.
For a more detailed list of service centers near you, visit KBB’s service center list.
Need Additional Help with Your P0451 Code?
In conclusion, as the P0451 code often presents no noticeable symptoms other than a Check Engine Light that displays on the vehicle’s dashboard, most people don’t take the code issue seriously. However, because the P0451 code issue can show up with other OBD-II code issues, it’s vital to get your vehicle immediately inspected by a proper technician to reduce the risk of further damage to your car.
For more information on the P0451 and other similar diagnostic codes, visit KBB’s vast library of OBD-II codes.
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