how to fix P0171 lean code in Ram 1500 DT (2019-Present)

Solution

1. Preparation

• Gather necessary tools and parts.
• Disconnect the negative battery terminal to ensure safety.

2. Inspect and Repair Vacuum Leaks

• Sub-steps:
  1. Visually inspect all vacuum hoses and connectors for cracks or disconnections.
  2. Use a smoke machine to detect leaks in the intake manifold and vacuum lines.
  3. Replace any damaged hoses with OEM or high-quality aftermarket parts.

3. Clean or Replace MAF Sensor

• Sub-steps:
  1. Disconnect the MAF sensor connector.
  2. Remove the MAF sensor from the intake duct with a Torx screwdriver.
  3. Clean the MAF sensor using an appropriate MAF cleaner spray. Avoid touching the sensor wire.
  4. If cleaning does not resolve the issue, replace the MAF sensor with a new one.

4. Check Fuel Pressure

• Sub-steps:
  1. Connect a fuel pressure gauge to the fuel rail test port.
  2. Turn the ignition on (do not start the engine) and check the fuel pressure reading.
  3. Compare the reading with the manufacturer's specifications (typically around 50-60 PSI for Ram 1500).
  4. If pressure is low, inspect the fuel pump, fuel filter, and fuel lines for issues. Replace as necessary.

5. Inspect Oxygen Sensors

• Sub-steps:
  1. Locate the upstream and downstream oxygen sensors in the exhaust system.
  2. Use a multimeter to check the sensor voltage output (should fluctuate between 0.1V and 0.9V).
  3. Replace any faulty oxygen sensors with OEM parts.

6. Verify ECT Sensor Function

• Sub-steps:
  1. Locate the ECT sensor and disconnect the electrical connector.
  2. Use a multimeter to measure the resistance of the sensor at varying temperatures (refer to service manual for resistance values).
  3. Replace the ECT sensor if it does not meet specifications.