P1447 – ELC System Closure Valve Flow Fault

Urgency Assessment

The P1447 code indicates an issue with the evaporative emission control (EVAP) system but is not typically an immediate safety concern. In most cases, the vehicle can continue to be driven for a short time, but should be inspected and repaired as soon as possible to prevent potential damage to the EVAP system and to maintain emissions compliance. However, if accompanied by drivability issues or other warning lights, it's best to have the vehicle towed to a repair facility.

Code Description and Meaning

P1447 is a manufacturer-specific code related to the EVAP system purge flow. The exact definition can vary slightly between manufacturers:

• For BMW/MINI: "Diagnostic Module Tank Leakage (DM-TL) Pump Current Too High During Switching Solenoid Test"
• For Nissan/Infiniti: "EVAP Control System Purge Flow Monitor"
• For Honda/Acura: "EVAP Control System Purge Flow Monitoring"

In general, this code indicates that the Engine Control Module (ECM) has detected an issue with the purge flow in the EVAP system, often related to excessive or insufficient flow.

Components Involved

EVAP System Overview

The EVAP system is designed to prevent fuel vapors from escaping into the atmosphere. Key components include:

• Fuel tank
• Charcoal canister
• Purge valve (also called purge solenoid)
• Vent valve
• Pressure sensor
• Various hoses and lines

Specific Parts Related to P1447

• DMTL (Diagnostic Module Tank Leakage) pump (BMW/MINI)
• Purge valve/solenoid
• EVAP canister
• Fuel tank pressure sensor

Function of Key Components

• DMTL pump: Creates vacuum to test EVAP system integrity (BMW/MINI specific)
• Purge valve: Controls flow of fuel vapors from the canister to the intake manifold
• EVAP canister: Stores fuel vapors until they can be purged into the engine
• Fuel tank pressure sensor: Monitors pressure in the fuel tank and EVAP system

Common Causes of P1447

1. Faulty purge valve/solenoid
2. Damaged or disconnected EVAP system hoses
3. Faulty DMTL pump (BMW/MINI)
4. Clogged or damaged EVAP canister
5. Faulty fuel tank pressure sensor
6. Loose or damaged gas cap
7. ECM software issues

Step-by-Step Diagnostic Procedure

1. Visual Inspection:

   • Check for loose, damaged, or disconnected EVAP hoses
   • Inspect the gas cap for proper sealing and damage
   • Look for any obvious damage to EVAP components

2. Electrical Testing:

   • Use a multimeter to check the resistance of the purge valve (typically 22-30 ohms)
   • Test the DMTL pump circuit for proper voltage and ground (BMW/MINI)

3. Pressure/Vacuum Testing:

   • Connect a smoke machine to the EVAP system to check for leaks
   • Use a vacuum pump to test the purge valve operation

4. Scan Tool Data:

   • Monitor EVAP system pressure during a purge cycle
   • Activate the purge valve using bidirectional controls
   • Check for any additional codes or pending codes

Potential Solutions and Repair Options

1. Replace faulty purge valve/solenoid
2. Repair or replace damaged EVAP hoses
3. Replace DMTL pump (BMW/MINI)
4. Clean or replace EVAP canister
5. Replace fuel tank pressure sensor
6. Replace gas cap
7. Update ECM software if applicable

Prevention Tips

1. Regularly inspect EVAP system hoses for damage
2. Ensure proper gas cap installation after refueling
3. Address check engine lights promptly to prevent compounded issues
4. Use high-quality fuel to reduce the risk of EVAP system contamination

Estimated Repair Costs

• Purge valve replacement: $100-$300 USD (€90-€270 EUR)
• EVAP canister replacement: $200-$600 USD (€180-€540 EUR)
• DMTL pump replacement (BMW/MINI): $300-$800 USD (€270-€720 EUR)
• Fuel tank pressure sensor: $150-$400 USD (€135-€360 EUR)

Labor costs typically range from 1-3 hours at $100-$150 USD (€90-€135 EUR) per hour.

Total repair costs can range from $200 to $1500 USD (€180 to €1350 EUR) depending on the specific issue and vehicle model.

DIY Repair Guide (for experienced mechanics)

1. Locate the purge valve, typically near the intake manifold or EVAP canister
2. Disconnect the electrical connector and any attached hoses
3. Remove mounting bolts and replace the valve
4. Reconnect hoses and electrical connector
5. Clear the code and perform a drive cycle to confirm the repair

For DMTL pump replacement (BMW/MINI):

1. Locate the pump under the vehicle, near the fuel tank
2. Disconnect the electrical connector and hoses
3. Remove mounting bolts and replace the pump
4. Reconnect hoses and electrical connector
5. Clear the code and perform a drive cycle

Related Issues and Fault Codes

• P0440: EVAP System Malfunction
• P0441: EVAP System Incorrect Purge Flow
• P0446: EVAP System Vent Control Circuit Malfunction
• P1440: Purge Valve Stuck Open (Nissan/Infiniti)

Vehicle-Specific Information

BMW/MINI models are particularly prone to P1447 codes due to DMTL pump failures. Nissan Maxima and Altima models from the late 1990s and early 2000s also commonly experience this issue.

By following this diagnostic and repair guide, engineers and mechanics should be able to effectively diagnose and resolve P1447 codes across various vehicle makes and models.

Frequently Asked Questions About P0472

What does the P1447 code mean?

P1447 generally indicates an issue with the Evaporative Emission Control (EVAP) system, specifically related to purge flow monitoring. The exact definition can vary slightly between manufacturers.

Is it safe to drive with the P1447 code?

While not typically an immediate safety concern, it’s best to have the issue diagnosed and repaired soon to prevent potential damage and maintain emissions compliance. If accompanied by drivability issues, consider having the vehicle towed.

What are the common causes of the P1447 code?

Common causes include a faulty purge valve/solenoid, damaged EVAP hoses, faulty fuel tank pressure sensor, loose gas cap, or issues with the EVAP canister.

How is the P1447 code diagnosed?

Diagnosis typically involves visual inspection of EVAP components, electrical testing of sensors and valves, pressure/vacuum testing of the EVAP system, and analysis of scan tool data.

What components are involved in the P1447 code?

Key components include the purge valve, EVAP canister, fuel tank pressure sensor, and various hoses and lines in the EVAP system.

Can I fix the P1447 code myself?

Some repairs, like replacing a gas cap, can be DIY. However, proper diagnosis often requires specialized tools and expertise. Complex repairs are best left to professionals.

How much does it cost to repair a P1447 code?

Repair costs can range from $100 to $1500 USD depending on the specific issue and vehicle model. Simple fixes like a gas cap replacement are inexpensive, while major component replacements can be costly.

Will the P1447 code clear itself?

The code may clear temporarily if the issue resolves, but will likely return if the underlying problem isn’t fixed. Proper diagnosis and repair are recommended.

What are the symptoms of a P1447 code?

Often, the only symptom is the check engine light. In some cases, you may notice a fuel odor or decreased fuel efficiency.

How can I prevent getting a P1447 code?

Regular maintenance, proper gas cap installation, and prompt attention to check engine lights can help prevent EVAP system issues.

Is the P1447 code the same for all vehicles?

While the general meaning is similar, the exact definition and diagnostic procedures can vary between manufacturers.

Can a P1447 code cause me to fail an emissions test?

Yes, an active P1447 code will typically cause a vehicle to fail an emissions test.

What other codes are commonly associated with P1447?

Related codes include P0440 (EVAP system malfunction), P0441 (incorrect purge flow), and P0446 (EVAP vent control circuit malfunction).

How long does it take to diagnose and repair a P1447 code?

Diagnosis can take 1-3 hours. Repair time varies depending on the specific issue, ranging from 30 minutes for simple fixes to several hours for complex repairs.

Can a bad O2 sensor cause a P1447 code?

While not directly related, faulty O2 sensors can sometimes trigger EVAP-related codes. However, it’s more likely that the P1447 is caused by an issue within the EVAP system itself.

Does the P1447 code affect fuel efficiency?

A malfunctioning EVAP system can potentially decrease fuel efficiency, though the impact may be minimal.

Can extreme weather conditions trigger a P1447 code?

Extreme temperatures can sometimes affect EVAP system operation, potentially triggering codes. However, a properly functioning system should be able to handle normal temperature variations.

Is it necessary to replace the entire EVAP system for a P1447 code?

Usually not. Most P1447 issues can be resolved by replacing specific components rather than the entire system.

Can aftermarket modifications cause a P1447 code?

Yes, certain modifications, especially those affecting the fuel system or engine management, can potentially interfere with EVAP system operation and trigger codes.

How often should the EVAP system be checked?

While there’s no specific schedule for EVAP system checks, it’s a good idea to have it inspected during routine maintenance, especially if you notice any fuel odors or decreased efficiency.