DTC P0171 & P0174

Issue Description

  • P0171 refers to "System Too Lean (Bank 1)".
  • P0174 refers to "System Too Lean (Bank 2)".

The Engine Control Module (ECM) detects an imbalance in the air-fuel mixture by analyzing data from the oxygen sensors and the Mass Airflow (MAF) sensor. When an excessively lean condition is detected, the ECM triggers these codes.

Dodge P0171, P0174 Error Code

Causes

  • Vacuum leaks.
  • Dirty or faulty MAF sensor.
  • Faulty oxygen (O2) sensors.
  • Clogged or failing fuel injectors.
  • Weak fuel pump or low fuel pressure.
  • Exhaust leaks before O2 sensors.
  • Dirty or failing PCV valve.

Symptoms

  • Check Engine Light (CEL) is On.
  • Rough idling or engine hesitation.
  • Reduced power and acceleration.
  • Increased fuel consumption.
  • Engine stalling or misfiring.
  • Unusual exhaust smell.

Solutions

  • Inspect and repair vacuum leaks.
  • Clean or replace MAF sensor.
  • Test and replace faulty O2 sensors.
  • Clean or replace fuel injectors.
  • Test and correct fuel pressure.
  • Repair exhaust leaks.
  • Replace faulty PCV valve.
  • Reset ECM and perform a test drive.

Dodge Error Codes

  • DTC P0121

    DTC P0121

    Throttle/Pedal Position Sensor A Range/Performance Problem

  • DTC P0128

    DTC P0128

    Coolant Thermostat (Coolant Temperature Below Thermostat Regulating Temperature)

  • DTC P0171 & P0174

    DTC P0171 & P0174

    Indicate issues related to the air-fuel mixture.

  • DTC P0301-P0308

    DTC P0301-P0308

    Individual cylinder misfires that caused by issues like a bad spark plug or coil, can also point to mechanical or fuel-related problems.