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P0451 Toyota Code - Evaporative Emission Control System Pressure Sensor Range / Performance

Quick Answer

5 hours after the ignition switch is turned off, the leak detection pump creates negative pressure (vacuum) in the Evaporative Emission (EVAP) system. Common causes include Faulty Canister Pump Module, Canister Pump Module harness is open or shorted, Canister Pump Module circuit poor electrical connection. Severity is Low - monitor the vehicle and repair when practical. The vehicle can usually be driven if no severe symptoms are present, but symptoms should be checked before extended driving.

What it means
P0451 Toyota indicates Evaporative Emission Control System Pressure Sensor Range / Performance.
Common causes
Common causes include Faulty Canister Pump Module, Canister Pump Module harness is open or shorted, Canister Pump Module circuit poor electrical connection.
Severity
Low - monitor the vehicle and repair when practical.
Can I drive?
The vehicle can usually be driven if no severe symptoms are present, but symptoms should be checked before extended driving.
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Code Popularity 32,981
How popular is this code, among other codes? Low
What is this?
Table of contents Created and updated by William Orellana on Mar 26, 2024
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Code P0451 Toyota Description

5 hours after the ignition switch is turned off, the leak detection pump creates negative pressure (vacuum) in the Evaporative Emission (EVAP) system. The Engine Control Module (ECM) monitors for leaks and actuator malfunctions based on the EVAP pressure. The leak detection pump creates negative pressure through the reference orifice. When the system is normal, the EVAP pressure is between 97 to 100 kPa(abs) [726 to 750 mmHg(abs) (Typical value)] and saturated within a minute. If the canister pressure sensor voltage output fluctuates rapidly for 10 seconds, the ECM stops the EVAP system monitor. The ECM interprets this as the canister pressure sensor voltage fluctuating, and stops the EVAP system monitor. The ECM then illuminates the MIL and stores the Diagnostic Trouble Code (DTC).
Alternatively, if the sensor voltage output does not change for 2 minutes, the ECM interprets this as the sensor being stuck, and stops the monitor. The ECM then illuminates the MIL and stores the DTC.
The Canister Pump Module is attached to the EVAP Canister and contains the Canister Pressure Sensor, the Leak Detection Pump, and the Vent Valve.
OBDII Code P0451 Toyota - Evaporative Emission Control System Pressure Sensor Range / Performance - AutoCodes.com
P0451 Toyota Code - Evaporative Emission Control System Pressure Sensor Range / Performance
What does this mean?

What are the Possible Causes of the DTC P0451 Toyota?

  • Faulty Canister Pump Module
  • Canister Pump Module harness is open or shorted
  • Canister Pump Module circuit poor electrical connection
  • Faulty Engine Control Module (ECM)

How to Fix the DTC P0451 Toyota?

Review the 'Possible Causes' above and visually examine the corresponding wiring harness and connectors. Check for damaged components and inspect connector pins for signs of being broken, bent, pushed out, or corroded.

What does this mean?

Code Tech Notes

There is a Factory Service Bulletin for the following Toyota models:
2003-2004 Toyota 4Runner
2003-2004 Toyota Tundra
2004 Toyota Camry
2004 Toyota Sienna
2004 Toyota Highlander
2004 Toyota Solara
Toyota Factory Service Bulletin OBDII Code P0451

What is the Cost to Diagnose the Code?

Labor: 1.0

To diagnose the P0451 Toyota code, it typically requires 1.0 hour of labor. Rates vary by location, vehicle, and shop. Many shops charge between $80–$150 per hour; dealerships and metro areas may be higher, independents may be lower.

Need more information about the P0451 Toyota code?

Need more information on how to fix the P0451 Toyota code? Get Access to Factory Service Manuals

Need Help with the Code?

Get the P0451 Toyota code diagnosed by a professional: Find a repair shop in your area

Information for Specific Toyota Models

About the author: William Orellana is a Master Mechanic and Mechanical Engineer with over 30 years of experience diagnosing and repairing vehicles. Learn more about his background.

Frequently Asked Questions about P0451 Toyota Code

1. What does the OBDII code P0451 mean on a Toyota?

P0451 indicates an issue with the evaporative emission control (EVAP) system pressure sensor, specifically that the sensor is providing readings outside the expected range or performance parameters.

2. What are the common symptoms of a P0451 code in a Toyota?

Symptoms may include an illuminated check engine light, poor fuel economy, a noticeable fuel odor, or difficulty filling the gas tank.

3. What causes a P0451 code on a Toyota?

Common causes include a faulty EVAP pressure sensor, damaged or disconnected wiring, a clogged EVAP vent line, or a malfunctioning charcoal canister.

4. Can a loose gas cap cause a P0451 code?

While a loose gas cap is a common cause for other EVAP codes, it is less likely to cause P0451. However, it’s still worth checking and tightening the gas cap first.

5. How can I fix a P0451 code on my Toyota?

Inspect and repair any damaged wiring or connectors, replace the EVAP pressure sensor if faulty, and check for clogs or damage in the EVAP system components.

6. Is it safe to drive with a P0451 code on a Toyota?

Driving with a P0451 code is generally safe, but it may lead to increased emissions or fuel vapor leaks. It’s best to address the issue promptly.

7. How much does it cost to repair a P0451 code on a Toyota?

Repair costs vary but typically range from $100 to $300, depending on whether the issue is with the sensor, wiring, or other EVAP components.

8. How do I diagnose a P0451 code on a Toyota?

Use an OBDII scanner to confirm the code, inspect the EVAP pressure sensor and its wiring, and check for clogs or leaks in the EVAP system.

9. Can a P0451 code clear itself on a Toyota?

The code may clear temporarily if the issue is intermittent, but it will return if the underlying problem is not resolved.

10. Does a P0451 code affect emissions testing for a Toyota?

Yes, a P0451 code will likely cause your vehicle to fail an emissions test due to the EVAP system malfunction.

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