P0451 Mercury Code - Evaporative Emission Control System Pressure Sensor Range/Performance
Quick Answer
The P0451 code for Mercury vehicles refers to an issue with the Evaporative Emission Control System Pressure Sensor, indicating a range/performance problem. Common causes include Faulty Pressure Sensor: The pressure sensor itself may be malfunctioning, providing incorrect readings to the vehicle's computer, EVAP System Leak: A leak in the EVAP system can cause pressure discrepancies and trigger the P0451 code, Damaged Wiring: Wiring connected to the pressure sensor may be damaged, leading to faulty readings. 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 Mercury indicates Evaporative Emission Control System Pressure Sensor Range/Performance.
- Common causes
- Common causes include Faulty Pressure Sensor: The pressure sensor itself may be malfunctioning, providing incorrect readings to the vehicle's computer, EVAP System Leak: A leak in the EVAP system can cause pressure discrepancies and trigger the P0451 code, Damaged Wiring: Wiring connected to the pressure sensor may be damaged, leading to faulty readings.
- 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.
Fix Your Car Smarter
Try the New AutoCodes App!
Get complete OBDII diagnostics, repair solutions, and cost estimates, plus AI chat support on demand.
Code P0451 Mercury Description
The P0451 code for Mercury vehicles refers to an issue with the Evaporative Emission Control System Pressure Sensor, indicating a range/performance problem. The Evaporative Emission Control System (EVAP) is responsible for preventing gasoline vapors from escaping into the atmosphere. The pressure sensor in this system monitors the pressure within the fuel tank and helps regulate the system's operation.
Common Causes of P0451 Mercury
- Faulty Pressure Sensor: The pressure sensor itself may be malfunctioning, providing incorrect readings to the vehicle's computer.
- EVAP System Leak: A leak in the EVAP system can cause pressure discrepancies and trigger the P0451 code.
- Damaged Wiring: Wiring connected to the pressure sensor may be damaged, leading to faulty readings.
- Loose or Missing Gas Cap: A loose or missing gas cap can cause pressure fluctuations in the fuel tank, triggering the P0451 code.
Symptoms of P0451 Mercury
- Check Engine Light: The most common symptom associated with the P0451 code is the illumination of the check engine light on the vehicle's dashboard.
- Decreased Fuel Efficiency: A malfunctioning EVAP system can lead to increased fuel consumption as the engine may not be running at optimal efficiency.
- Strong Fuel Odor: A noticeable gasoline odor inside or outside the vehicle may indicate a leak in the EVAP system.
- Failed Emissions Test: Vehicles with the P0451 code may fail emissions tests due to increased emissions output.
How to Fix P0451 Mercury
- Diagnose the Issue: Use a diagnostic scanner to retrieve the specific trouble code and pinpoint the source of the problem within the EVAP system.
- Inspect Pressure Sensor: Check the pressure sensor for any signs of damage or malfunction, and replace if necessary.
- Repair EVAP System: Address any leaks in the EVAP system, repair damaged wiring, and ensure all connections are secure.
- Replace Gas Cap: If a loose or missing gas cap is the cause of the issue, replace it with a properly fitting cap to maintain proper pressure in the fuel tank.
Cost to Fix P0451 Mercury
The cost of repairing the P0451 code on a Mercury vehicle can vary depending on the specific issue causing the code and the labor rates of the auto repair shop. On average, the repair cost for this issue can range from $100 to $300, including parts and labor. It's important to consider that diagnosis time and labor rates at auto repair shops can vary based on location, vehicle make and model, and engine type. Checking with local shops for estimates tailored to your specific situation is recommended.
Tech Notes for P0451 Mercury
2005-2008 Mercury Mariner
2006-2008 Mercury Mariner Hybrid
2005-2008 Mercury Mariner Factory Service Bulletin OBDII Code P0451
When is the Code Detected?
Need more information about the P0451 Mercury code?
Need more information on how to fix the P0451 Mercury code? Get Access to Factory Service Manuals
Need Help with the Code?
Get the P0451 Mercury code diagnosed by a professional: Find a repair shop in your area
Frequently Asked Questions about P0451 Mercury Code
What does the OBDII code P0451 mean for a Mercury vehicle?
The P0451 code indicates a problem with the Evaporative Emission Control System (EVAP) pressure sensor, which is detecting a range or performance issue.
What are the symptoms of the P0451 code in a Mercury?
Common symptoms include an illuminated Check Engine Light, failed emissions tests, and in some cases, a noticeable fuel odor.
What causes the P0451 code to be triggered?
Possible causes include a faulty EVAP pressure sensor, damaged wiring or connectors, a clogged EVAP vent valve, or a leaking EVAP system.
Can the P0451 code affect drivability?
Typically, the P0451 code does not affect drivability, but it may lead to increased emissions or fuel odors if not repaired.
How do you diagnose the P0451 code on a Mercury?
Diagnosis involves checking the EVAP pressure sensor, inspecting wiring and connectors, verifying the integrity of the EVAP system, and using a scan tool to monitor sensor readings.
Can a loose gas cap cause the P0451 code?
A loose or damaged gas cap usually triggers a different EVAP-related code, but it’s still worth checking as part of the diagnosis.
How do you fix the P0451 code in a Mercury?
Repairs may include replacing the EVAP pressure sensor, repairing wiring or connectors, cleaning or replacing the EVAP vent valve, or addressing any leaks in the EVAP system.
Is it safe to drive with the P0451 code?
Yes, it’s generally safe to drive, but you should address the issue promptly to avoid potential emissions problems or fuel vapor leaks.
How much does it cost to fix the P0451 code?
Repair costs vary, ranging from $50 for a gas cap replacement to $200-$400 for sensor or wiring repairs, depending on the exact issue.
Can I clear the P0451 code without fixing it?
You can clear the code with an OBDII scanner, but it will likely return if the underlying issue isn’t resolved.
Discuss the causes and fixes for P0451 Mercury OBDII Code
-
my check engine light came on, detected a ROM error, aal failed, back on went off after filling the gas, dealer said without light on, they don't know what should I do
-
What model and year is your Mercury? You should wait until the light comes back ON. EVAP system codes will not cause any engine performance problem or damage your car. If comes back again, have the dealer inspected.
-
check engine light on, and blinking overdrive light on, 2006 mercury mariner, 123,000 miles
-
What codes did you get? the overdrive system or transmission is not related to the P0451 code.
-
My Mariner 2005 3.0 Lt, V6, has check engine light on and show me a message "Service Emission system", could you help me, please? Thanks ¡¡
-
There is a factory service bulletin for that code (See "Tech notes" above). The bulletin states that the condition may be caused by water/moisture or other contamination entering the fuel filler vent line and then freezing and/or causing a blockage. The bulletin suggest how to fix the problem,
-
On my 08 mariner I have no check engine light, but does a period. 3 beep sequence. It's my first new car and I have no clue how this thing works. Any ideas?
-
The beep could be for something else. Beside the beep, are there any driveability problems? Not sure you are able to get codes with beeps.
Fix Your Car Smarter
Try the New AutoCodes App!
Get complete OBDII diagnostics, repair solutions, and cost estimates, plus AI chat support on demand.