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 stops gas fumes from escaping. It's like when you forget to put the cap back on a soda bottle, and the bubbles escape.
The P149A code indicates an issue with the control circuit of the EVAP system shutoff valve, which is responsible for sealing the fuel system to prevent vapor leaks.
The EVAP system shutoff valve is a component of the vehicle's evaporative emission control system. It is designed to close the system and prevent fuel vapors from escaping into the atmosphere. The control circuit for this valve is monitored by the engine control module (ECM), and a fault is detected when the circuit is open, shorted, or not functioning as expected.
• Check Engine Light is on
• Failed emissions test
• Noticeable fuel odor
• Faulty EVAP shutoff valve
• Wiring issues such as open or shorted circuit
• Faulty ECM
EVAP: Evaporative Emission Control System
ECM: Engine Control Module
• Use an OBD-II scanner to confirm the code
• Inspect the EVAP shutoff valve and associated wiring
• Test the valve for proper operation
• Replace the EVAP shutoff valve if faulty
• Repair or replace damaged wiring
• Replace the ECM if necessary
• OBD-II scanner
• Multimeter
• Basic hand tools
$100 - $400
Moderate
• Toyota Camry
• Honda Accord
• Ford F-150
• Regularly inspect the EVAP system components
• Ensure gas cap is tightly secured
• Perform routine vehicle maintenance
Emissions Control Issue
• Avoid driving with a full tank until fixed
• Check for fuel odors and report them
• Consult a professional mechanic for diagnosis
Check with the vehicle manufacturer for emissions-related warranty coverage.
This code has been associated with issues in vehicles that have older or worn EVAP systems, particularly in models with high mileage.
Moderate – While not immediately critical, it should be addressed to prevent emissions and potential fuel economy issues.
Driving with an emissions system fault may be illegal in some areas due to environmental regulations.
• Engine at operating temperature
• Vehicle in a safe, stationary position
The EVAP shutoff valve is typically located near the fuel tank or along the EVAP canister.
Q: Can I drive with a P149A code?
A: You can drive short distances, but it's best to fix the issue to avoid emissions problems.
Q: Will this code affect my car's performance?
A: It may not affect performance directly, but it can lead to increased emissions and fuel odors.
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Network faults often require full-system access instead of a generic code reader alone.
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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.