AutoCodesLexus – P0451 Lexus

P0451 Lexus 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 Lexus 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 14,802
How popular is this code, among other codes? Low
Table of contents Created and updated by William Orellana on Mar 26, 2024
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Code P0451 Lexus 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 Lexus - Evaporative Emission Control System Pressure Sensor Range / Performance - AutoCodes.com
P0451 Lexus Code - Evaporative Emission Control System Pressure Sensor Range / Performance

What are the Possible Causes of the DTC P0451 Lexus?

  • 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 Lexus?

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 is the Cost to Diagnose the Code?

Labor: 1.0

To diagnose the P0451 Lexus 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.

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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 Lexus Code

What does OBDII code P0451 mean on a Lexus?

Code P0451 indicates an issue with the Evaporative Emission Control System Pressure Sensor, specifically related to its range or performance.

What are the common symptoms of code P0451 on a Lexus?

Common symptoms include the check engine light turning on, poor fuel economy, difficulty refueling, and, in some cases, a faint fuel odor.

What causes the P0451 code on a Lexus?

Possible causes include a faulty fuel tank pressure sensor, a damaged or disconnected EVAP system hose, wiring issues, or a malfunctioning purge or vent valve.

Can I drive my Lexus with a P0451 code?

Yes, you can drive with a P0451 code, but it’s recommended to address the issue promptly to avoid potential damage to the EVAP system and ensure your vehicle passes emissions tests.

How is the P0451 code diagnosed on a Lexus?

A mechanic will typically use an OBDII scanner to confirm the code, inspect the EVAP system components, check the fuel tank pressure sensor, and test the associated wiring for faults.

How do I fix the P0451 code on my Lexus?

Repairs may involve replacing the fuel tank pressure sensor, repairing or replacing damaged EVAP hoses, fixing wiring issues, or replacing a faulty purge or vent valve.

What is the fuel tank pressure sensor, and why is it important?

The fuel tank pressure sensor measures pressure changes in the EVAP system to detect fuel vapor leaks. It’s essential for maintaining proper emissions control.

How much does it cost to fix the P0451 code on a Lexus?

Repair costs can vary but typically range from $100 to $400, depending on whether the issue is a simple sensor replacement or a more extensive repair.

Can a loose gas cap cause the P0451 code on a Lexus?

While a loose gas cap can trigger some EVAP-related codes, P0451 is more commonly caused by issues with the fuel tank pressure sensor or EVAP system components.

How can I prevent the P0451 code from returning?

Regular maintenance of the EVAP system, ensuring the gas cap is properly tightened, and addressing any fuel system issues promptly can help prevent the code from recurring.

Discuss the causes and fixes for P0451 Lexus OBDII Code

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