Easy one-page printout for the garage or repair shop
This summary uses the existing diagnostic information shown in full below.
Your car has a system that helps control fuel vapors. This code means there's a problem with the part that shuts off the fuel vapor system, like a light switch that isn't working right.
The P149C code indicates that the voltage in the circuit controlling the EVAP system shutoff valve is higher than expected.
The EVAP (Evaporative Emission Control) system prevents fuel vapors from escaping into the atmosphere. The shutoff valve is part of this system, and it controls the flow of vapors. A 'circuit high' condition means the electrical circuit has a higher voltage than normal, suggesting a wiring issue or a malfunctioning component.
• Check Engine Light is on
• Increased emissions
• Possible fuel odor
• Faulty EVAP shutoff valve
• Wiring issues such as short circuits
• Malfunctioning control module
EVAP: Evaporative Emission Control System
Circuit High: Indicates higher than expected voltage in a circuit
• Use an OBD-II scanner to confirm the code.
• Inspect the EVAP shutoff valve and wiring for damage.
• Test the voltage in the circuit with a multimeter.
• Replace the EVAP shutoff valve if faulty.
• Repair or replace damaged wiring.
• Reset the control module if necessary.
• OBD-II scanner
• Multimeter
• Basic hand tools
$100 - $300
Moderate
• Toyota Camry
• Honda Accord
• Ford Focus
• Regularly inspect EVAP system components.
• Keep the fuel cap tight and in good condition.
• Perform regular vehicle maintenance checks.
Sensor Issue
• Have a professional diagnose the issue if you're not comfortable with electrical systems.
• Avoid driving with a persistent Check Engine Light.
Check your vehicle's warranty for coverage on emissions-related components.
This code has been associated with emissions system issues in vehicles since the introduction of OBD-II systems in the mid-1990s.
Moderate – It should be addressed soon to prevent emissions issues.
Driving with a malfunctioning EVAP system can lead to increased emissions, which may be illegal in some areas.
• Engine running
• Vehicle at operating temperature
The EVAP shutoff valve is typically located near the fuel tank or along the EVAP system lines.
Q: Can I drive with a P149C code?
A: Yes, but it's best to fix it soon to avoid emissions problems.
Q: Will a P149C code affect my fuel economy?
A: It might not directly affect fuel economy, but it can lead to increased emissions.
High-End · Full-system diagnostics
A full-system bidirectional platform aimed at advanced DIY users and professional diagnostic workflows.
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.
View on AmazonThese are optional diagnostic tools, not guaranteed fixes. As an Amazon Associate I earn from qualifying purchases.
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.