Easy one-page printout for the garage or repair shop
This summary uses the existing diagnostic information shown in full below.
This code means that the car's computer detected a problem with the air flow or pressure in the secondary air system on one side of the engine. It's like when you're blowing air into a balloon and the balloon isn't filling up as expected.
The OBD-II code P145C indicates an issue with the initialization or pressure difference of the Secondary Air Injection System on Bank 1 across two driving cycles.
The Secondary Air Injection System helps reduce emissions by injecting fresh air into the exhaust stream. The system uses sensors to monitor air flow and pressure. Code P145C is triggered when the system detects a pressure difference between two driving cycles, indicating a potential malfunction in the air flow or pressure sensor on Bank 1.
• Check Engine Light is on
• Poor engine performance
• Increased emissions
• Unusual noises from the engine
• Faulty air flow/pressure sensor
• Blocked or leaking air injection system
• Damaged or disconnected hoses
• Faulty secondary air injection pump
Secondary Air Injection System: A system that injects fresh air into the exhaust stream to help reduce emissions.
Bank 1: Refers to the side of the engine that contains cylinder number one.
• Check for any other related codes.
• Inspect the secondary air injection system for leaks or blockages.
• Test the air flow/pressure sensor for proper operation.
• Inspect wiring and connections for damage or corrosion.
• Replace faulty air flow/pressure sensor.
• Repair or replace damaged hoses or connections.
• Clean or replace the secondary air injection pump.
• Clear the code and test drive the vehicle to ensure the issue is resolved.
• OBD-II scanner
• Multimeter
• Vacuum gauge
• Basic hand tools
$150 - $500
Moderate
• BMW 3 Series
• Audi A4
• Mercedes-Benz C-Class
• Regularly inspect and maintain the air injection system.
• Replace air filters as recommended.
• Ensure all hoses and connections are secure and undamaged.
Sensor Issue
• Address the issue promptly to avoid increased emissions.
• Consult with a professional mechanic if unsure about repairs.
Check with the vehicle manufacturer for warranty coverage on emissions-related components.
This code is often associated with vehicles that have a history of emissions system issues, particularly in models with complex air injection systems.
Moderate – Address the issue to prevent potential damage to the emissions system and ensure compliance with emissions standards.
Operating a vehicle with a malfunctioning emissions system may violate local emissions regulations and contribute to environmental pollution.
• Engine at operating temperature
• Vehicle driven for at least two cycles
The air flow/pressure sensor is typically located near the secondary air injection pump, which is often found in the engine bay.
Q: Can I drive with a P145C code?
A: It's possible to drive with this code, but it's recommended to fix it soon to avoid increased emissions and potential engine performance issues.
Q: Will a P145C code affect my vehicle's emissions test?
A: Yes, this code can cause your vehicle to fail an emissions test due to increased emissions.
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Good for emissions-related codes because it exposes readiness monitors and live powertrain data.
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Helpful for finding EVAP and vacuum leaks that are hard to see with visual inspection alone.
Helpful for tracking down EVAP and vacuum leaks that can trigger emissions faults.
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Specialty · O2 sensor socket
Helpful when the code points toward exhaust or oxygen-sensor work and space is tight.
Useful when the diagnosis points toward oxygen-sensor removal or replacement.
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Fitment Required · Vehicle-fitment part
Relevant for airflow, fuel-trim, and intake-metering faults after confirming the sensor is actually at fault.
Airflow and fuel-trim codes can involve the mass air flow sensor after proper diagnosis.
Verify the sensor design and fitment for your exact vehicle.
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.