What Are Some Common Fixes to OBD II Fault Codes?

Common fixes that solve on-board diagnostic fault codes in a vehicle include replacing the oxygen sensor, tightening or replacing the gas cap, replacing the catalytic converter, replacing the mass airflow sensor and replacing one or more spark plugs or spark plug wires. Check your vehicle's on-board diagnostic system using an ODB II fault code scan tool, or bring the vehicle to an automotive repair specialist to discover the precise cause of the error.

One of the most common causes of a vehicle's on-board diagnostic system producing a fault code is a faulty oxygen, or O2, sensor. The oxygen sensor is responsible for measuring the amount of fresh oxygen in the exhaust system. Failure to replace a faulty O2 sensor causes the vehicle to burn more fuel than is necessary, reducing fuel economy, and leads to damage of the spark plugs or catalytic converter.

When the vehicle's gas cap is missing, damaged or loose, the on-board diagnostic system generates a fault code. This common problem allows fuel to escape the fuel tank via evaporation, leading to loss of fuel economy and hydrocarbon pollution. Similarly, a damaged catalytic converter both causes the on-board diagnostic system to produce a fault code and releases carbon monoxide into the atmosphere. A vehicle with a damaged catalytic converter is unable to pass emissions testing and will operate poorly compared to the same vehicle with a properly functioning catalytic converter.