my Renault Clio V (2019-Present) has a check engine light and code P0171, what's the fix?

Solution

1. Preparation

• Gather tools and parts.
• Disconnect the negative battery terminal to prevent electrical shorts.
• Tools required: OBD-II scanner, socket set, fuel pressure gauge, multimeter, cleaning solvent, and rags.

2. Inspect and Repair Vacuum Leaks

• Check all vacuum hoses for cracks or disconnections.
• Use a smoke machine or carburetor cleaner to identify leaks.
• Replace any damaged hoses or gaskets found during inspection.

3. Fuel Pressure Check

• Connect the fuel pressure gauge to the fuel rail.
• Turn the ignition to the ON position (do not start the engine) and check the pressure reading.
  • Expected pressure should be within manufacturer specifications (typically around 3.5-4.5 bar for most Renault models).
• If pressure is low, inspect the fuel pump and filter for issues, replacing them as necessary.

4. MAF Sensor Cleaning

• Locate the MAF sensor, typically situated between the air filter and the throttle body.
• Disconnect the electrical connector and unscrew the sensor from the intake.
• Spray MAF cleaner onto the sensor element, avoiding contact with the wiring.
• Allow the sensor to dry completely before reinstallation.

5. Inspect Fuel Injectors

• Disconnect the fuel rail and inspect the injectors for proper operation.
• Use a multimeter to test the resistance of each injector, comparing results to manufacturer specifications.
• Replace any injectors that are outside of the specified range.

6. Reassembly and Testing

• Reassemble any components removed during inspection and repair.
• Reconnect the battery terminal and clear the check engine codes using the OBD-II scanner.
• Start the engine and monitor for any check engine light reoccurrence.