P0442 Mercury Code - Evaporative Emission System Leak Detected Small Leak
Quick Answer
The Engine Control Module (ECM) tests the Evaporative Emission (EVAP) system for the following conditions: - Large and small leaks - Excess vacuum - Purge flow during non-commanded conditions - Fuel Level and Fuel Pressure sensor faults - EVAP Purge and Vent Valve faults The ECM monitors the Fuel Tank Pressure sensor in order to determine the level of vacuum/pressure in the EVAP system. Common causes include Missing or loose fuel cap, Incorrect fuel filler cap used, Fuel filler cap remains open or fails to close. 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
- P0442 Mercury indicates Evaporative Emission System Leak Detected Small Leak.
- Common causes
- Common causes include Missing or loose fuel cap, Incorrect fuel filler cap used, Fuel filler cap remains open or fails to close.
- 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.
Code P0442 Mercury Description
- Large and small leaks
- Excess vacuum
- Purge flow during non-commanded conditions
- Fuel Level and Fuel Pressure sensor faults
- EVAP Purge and Vent Valve faults
The ECM monitors the Fuel Tank Pressure sensor in order to determine the level of vacuum/pressure in the EVAP system. The ECM commands both the EVAP Purge Solenoid and the EVAP Vent Valve ON when the conditions are met in order to apply an engine vacuum to the EVAP system. The ECM commands the EVAP Purge Solenoid OFF once the system has reached a predetermined level of vacuum. This test verifies if a vacuum can be achieved in the EVAP system. Failure to develop a vacuum may be caused by a large leak or a restriction.
The Diagnostic Trouble Code (DTC) will set when a malfunction is detected when the EVAP control system has a leak, the EVAP control system does not operate properly.
What are the Possible Causes of the DTC P0442 Mercury?
- Missing or loose fuel cap
- Incorrect fuel filler cap used
- Fuel filler cap remains open or fails to close
- Foreign matter caught in fuel filler cap
- EVAP canister or fuel tank leaks
- EVAP system hose leaking
- Fuel tank leaking
How to Fix the DTC P0442 Mercury?
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.
Code Tech Notes
There is a factory service bulletin for the following Mercury vehicles:
1997-1999 Mercury Tracer
1997-2000 Mercury Mystique
1997-2003 Mercury Grand Marquis
1997-2003 Mercury Sable
1999-2002 Mercury Cougar
1997-2003 Mercury Mountaineer
Mercury Factory Service Bulletin OBDII Code P0442
What is the Cost to Diagnose the Code?
Labor: 1.0
To diagnose the P0442 Mercury 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 P0442 Mercury code?
Need more information on how to fix the P0442 Mercury code? Get Access to Factory Service Manuals
Need Help with the Code?
Get the P0442 Mercury code diagnosed by a professional: Find a repair shop in your area
Frequently Asked Questions about P0442 Mercury Code
1. What are the common symptoms of OBDII code P0442 on a Mercury vehicle?
The common symptoms of P0442 include the check engine light illuminating on the dashboard, fuel odor near the vehicle, and potential issues with passing emissions tests.
2. What are the possible causes of OBDII code P0442 on a Mercury?
The code P0442 on a Mercury is often caused by a small leak in the evaporative emission system, such as a loose gas cap, cracked or damaged hoses, or a faulty purge valve.
3. How serious is OBDII code P0442 on a Mercury?
While P0442 is not a critical issue that affects the immediate drivability of the vehicle, it should be addressed promptly to prevent potential damage to the emission control system and to ensure the vehicle passes emissions tests.
4. Can a loose gas cap trigger OBDII code P0442 on a Mercury?
Yes, a loose, damaged, or missing gas cap is a common cause of P0442 on a Mercury. Ensuring the gas cap is properly tightened or replacing it can often resolve the issue.
5. How can I diagnose and repair OBDII code P0442 on my Mercury?
To diagnose P0442, a mechanic may perform a smoke test to identify the source of the leak. Depending on the cause, repairs may involve replacing hoses, valves, or the gas cap to fix the issue.
6. Is it safe to continue driving my Mercury with OBDII code P0442?
While driving with P0442 may not immediately harm your vehicle, it is essential to address the underlying issue promptly to prevent potential damage to the emission control system and ensure proper vehicle performance.
7. Can extreme weather conditions trigger OBDII code P0442 on a Mercury?
Extreme weather conditions, such as temperature fluctuations, can sometimes exacerbate existing issues in the evaporative emission system, potentially leading to the triggering of code P0442.
8. Will resetting the check engine light temporarily fix OBDII code P0442 on a Mercury?
Resetting the check engine light may temporarily clear the code, but if the underlying issue causing P0442 is not addressed, the code is likely to reappear after some driving cycles.
9. How long does it typically take to repair OBDII code P0442 on a Mercury?
The time to repair P0442 on a Mercury can vary depending on the exact cause of the issue and the availability of parts. In most cases, a professional repair job can be completed within a few hours.
10. Can I fix OBDII code P0442 on my Mercury by myself, or should I seek professional help?
While some simple causes like a loose gas cap can be fixed by the vehicle owner, diagnosing and repairing more complex issues related to code P0442 may require professional expertise and specialized tools, so seeking help from a mechanic is often recommended.
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