how to troubleshoot P0171 code in Volkswagen Golf MK7 (2015-2019)?

Solution

1. Preparation

• Gather tools and parts required.
• Disconnect the negative battery terminal to prevent electrical shorts.

2. Inspect Air Intake System

• Tools Required: Screwdriver, flashlight
• Inspect all hoses and connections for cracks or disconnections.
• Tighten or replace any loose or damaged hoses.
• Safety Warning: Ensure engine is cool before working on the air intake system.

3. Clean or Replace MAF Sensor

• Tools Required: MAF cleaner, soft cloth
• Remove the MAF sensor from the air intake duct.
• Spray MAF sensor cleaner onto the sensing element and let it dry completely.
• Reinstall the sensor ensuring that it is secured properly.

4. Check Fuel Pressure

• Tools Required: Fuel pressure gauge
• Connect the fuel pressure gauge to the fuel rail test port.
• Turn the ignition to the "ON" position (do not start) and check the pressure reading against manufacturer specifications (usually around 50-60 psi).
• If pressure is low, check the fuel pump and filter for issues.

5. Inspect Fuel Injectors

• Tools Required: Multimeter, injector cleaner
• Disconnect the fuel injector connectors and use a multimeter to check for proper resistance (typically around 12-16 ohms).
• If injectors are clogged, use an injector cleaner or replace them if necessary.

6. Check Engine Coolant Temperature Sensor

• Tools Required: Multimeter
• Locate the sensor and disconnect its connector.
• Use a multimeter to measure resistance; compare readings with manufacturer specifications for temperature vs. resistance.
• Replace the sensor if readings do not match specifications.