Easy one-page printout for the garage or repair shop
This summary uses the existing diagnostic information shown in full below.
This code means there's a problem with the part of the car that checks if the gas tank is leaking. It's like when you have a balloon with a tiny hole, and the pump that checks for leaks isn't working right.
The P1446 code indicates that the Diagnostic Module Tank Leakage (DM TL) pump is experiencing a high voltage condition in its control circuit.
The DM TL pump is part of the evaporative emissions system, which checks for leaks in the fuel system to prevent gas vapors from escaping into the atmosphere. A high voltage condition in the pump control circuit suggests an electrical issue, such as a short circuit or a faulty pump.
• Check Engine Light illuminated
• Failed emissions test
• Possible fuel odor
• Faulty DM TL pump
• Wiring issues such as short circuits or open circuits
• Faulty control module
DM TL: Diagnostic Module Tank Leakage
OBD-II: On-Board Diagnostics, Second Generation
• Use an OBD-II scanner to confirm the P1446 code.
• Inspect the wiring and connectors for damage or corrosion.
• Test the DM TL pump for proper operation and voltage levels.
• Replace the DM TL pump if found faulty.
• Repair or replace damaged wiring or connectors.
• Replace the control module if necessary.
• OBD-II scanner
• Multimeter
• Basic hand tools
$150 - $400
Moderate
• BMW 3 Series
• BMW 5 Series
• BMW X5
• Regular maintenance checks of the fuel system
• Inspect wiring for wear and tear
• Ensure gas cap is properly sealed
Sensor Issue
• Have the vehicle inspected by a professional if the Check Engine Light is on.
• Avoid overfilling the gas tank.
Check with the vehicle manufacturer for emissions-related warranty coverage.
P1446 is a common code in vehicles with advanced evaporative emissions systems, particularly in models with known electrical issues.
Moderate – It won't immediately affect drivability but should be addressed to ensure emissions compliance.
Ignoring emissions-related issues can lead to fines and increased pollution.
• Engine at normal operating temperature
• Vehicle parked in a well-ventilated area
The DM TL pump is typically located near the fuel tank or in the rear of the vehicle.
Q: Can I drive with a P1446 code?
A: Yes, but it's best to fix it soon to avoid emissions issues.
Q: Will a P1446 code cause my car to fail an emissions test?
A: Yes, this code can cause your vehicle to fail an emissions test.
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Universal · Digital multimeter
A solid entry-level multimeter for voltage, continuity, resistance, and basic electrical troubleshooting.
Helpful for checking voltage drops, grounds, and basic circuit health when modules are not communicating.
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Universal · Wire connectors and repair kit
Useful when diagnosis points toward damaged wiring, corroded terminals, or connector repairs.
Useful if diagnosis points toward damaged connectors, wiring, or terminal repairs.
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Fitment Required · Vehicle-fitment part
Relevant when EVAP diagnosis points toward purge-flow or purge-control faults.
EVAP diagnosis often includes purge-flow and valve-control faults.
Confirm the failed valve and exact fitment before buying parts.
View options on AmazonThese parts may be related to this fault category, but a code by itself does not confirm exact fitment or guarantee that replacing a part will solve the problem.