This code monitors the oxygen sensor voltage and when it sets, it means that the PCM sees that it has remained low for over a predetermined amount of time, usually 2-4 minutes, but that varies depending on manufacturer.

TechShop discusses the relationship between clearing DTCs and readiness monitors.

An ASE Certified Technician breaks down DTC P0300, identifies the symptoms and causes and walks listeners through a diagnostic solution.

TechShop's ASE-certified technicians share and review a Technical Service Bulletin that applies to 2016 to 2019 Ford Fiesta vehicles with DTC P0128.

An ASE Certified technician walks listeners through an unusual problem on a 2005 GMC Sierra 2500 4WD truck. This tip is brought to you by AllData.

When P0172 is stored, it means that the control unit has recognized through the readings from the oxygen or air/fuel ratio sensors that there is a lack of oxygen in the exhaust, representing too much fuel in the combustion process.

P0455 is a common EVAP trouble code and one whose description quite often accurately reflects what is causing the problem. The purpose of the evaporative emission system is to prevent the fuel vapors in the gas tank from escaping into the atmosphere and when this code sets, it’s a good bet that they are.

An ASE Certified Technician breaks down DTC P0171, identifies the symptoms and causes and walks listeners through a diagnostic solution.

Our scan tool is reading a diagnostic trouble code of P0401- EGR Insufficient Flow. An ASE Certified Technician identifies the symptoms and causes of a P0401, and walks listeners through a diagnostic solution.

An ASE Certified Technician identifies the symptoms and causes of a P0420, walks listeners through a diagnostic solution.