Description of DTC code P0171

The DTC code P0171 is generic and basically gives us to understand that a very low condition has been detected in the oxygen sensor in bank 1, that is, there is an excess of oxygen in the exhaust gases. In the 6, 8 and 10 cylinder engines, bank 1 corresponds to the side of the engine that has cylinder 1.

This diagnostic code is very common and is activated by the Waterside Sensor, which provides an air reading which are: When the fuel leaves the engine and PCM cylinders of the powertrain. This reading is adjusted, in order to keep the motor running at an optimum ratio of 14.7: 1. In case there is a fault and the PCM cannot maintain it 14.7: 1, the diagnostic code P0171 is obtained.

Symptoms of fault code P0171

  • The Check Engine light is on.
  • There is excessive fuel consumption.

Causes of OBD2 P0171

An error code P0171 can have one or more of the following problems:

  • The TBI Fuel Injection System does not work correctly, due to an obstruction or contamination.
  • Filter or fuel lines capped.
  • The Check valve on the fuel pump may be faulty.
  • The PCV valve may be leaking or stuck open.
  • Some leakage in the system (EVAP) components or in the Fuel Rail Pressure Sensor (FRP).
  • Mass Air Flow Sensor may be damaged.


Possible solutions of the DTC code P0171

To solve the fault code P0171 you can review the following components:

  • Check all vacuum and PCV hoses.
  • Clean the filter in case of getting elements that could affect its proper functioning.
  • Make sure that the fuel pressure is at its optimum level.
  • Clean the MAF sensor, and when installing it remember to take into account that it must be dry, otherwise it could be damaged.

Codes related to P0171

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