how to fix P0171 code on a Honda Accord 9th Generation (2013-2017)

Solution

1. Preparation

• Gather tools: OBD-II scanner, multimeter, vacuum gauge, socket set, screwdriver set, and cleaning supplies.
• Ensure the vehicle is parked on a level surface and the engine is cool.
• Disconnect the negative battery terminal to prevent any electrical shorts.

2. Inspect Air Intake System

• Remove the engine cover, if applicable, using the socket set.
• Visually inspect all vacuum hoses for cracks or disconnections; replace any damaged hoses.
• Use a vacuum gauge to check for leaks in the intake manifold.

3. Clean and Test Mass Air Flow Sensor

• Disconnect the MAF sensor connector.
• Remove the MAF sensor from the air intake duct.
• Clean the sensor wire with MAF cleaner; do not touch the wire with fingers or tools.
• Reinstall the MAF sensor and reconnect the connector.

4. Check Fuel Delivery System

• Connect the fuel pressure gauge to the fuel rail test port.
• Turn the ignition on (do not start the engine) and observe the fuel pressure; it should match manufacturer specifications (typically around 40-50 psi).
• If pressure is low, inspect the fuel pump, fuel filter, and fuel lines for blockages or damage.

5. Inspect Oxygen Sensors and Exhaust System

• Locate the upstream oxygen sensor (pre-catalytic converter).
• Use a multimeter to check the sensor's voltage output while the engine is running; it should fluctuate between 0.1 to 0.9 volts.
• Inspect the exhaust system for leaks that could affect sensor readings.

6. Clean Throttle Body

• Remove the air intake duct connected to the throttle body.
• Use throttle body cleaner and a soft cloth to clean the inside of the throttle body.
• Reassemble all components ensuring all connections are secure.