• The fault code P0172 indicates that the air-to-fuel ratio in the engine is too rich, meaning there is too much fuel being injected into the combustion chamber and not enough air. This can cause the engine to run poorly, reduce fuel economy, and increase emissions.

Possible Symptoms:

  • Illuminated check engine light

  • Decreased fuel economy

  • Rough idle or stalling

  • Reduced engine power or acceleration

  • Strong smell of gasoline from the exhaust

Possible Causes:

  • Faulty oxygen sensor

  • Dirty or clogged air filter

  • Malfunctioning fuel injector

  • Vacuum leak

  • Failed fuel pressure regulator

  • Malfunctioning mass airflow sensor (MAF)

  • Faulty engine control module (ECM)

Related Parts:

  • Fuel Injection System: Fuel injection system controls the amount of fuel to be delivered through the fuel injectors. Problems lead to engine misfire, engine stalling

Possible Solutions:

  • Replace faulty oxygen sensor

  • Clean or replace dirty air filter

  • Check and replace malfunctioning fuel injector

  • Inspect and repair vacuum leaks

  • Replace failed fuel pressure regulator

  • Clean or replace malfunctioning mass airflow sensor

  • Replace the engine control module (ECM) if necessary