Air mass flow sensor fault o2 sensor

As a rule, the Check Engine light only comes on if a fault affects emissions. A bad sensor can certainly do that. There are a large number of codes relating to oxygen sensor faults. There are also a lot of faults that are often incorrectly thought to be caused by a bad oxygen sensor (also referred to as an OSensor). The mass air flow reference voltage and ground must be checked at the sensor connector.

The signal voltage or frequency needs to be checked at different engine RPMs and compared to the reference chart. It is common for the mass airflow sensor to get dirty (if the air filter is dirty) and lose the ability to read the amount of air coming in the engine. If the vacuum hoses are leaking, it will give the same error code as mass airflow sensor failure.

How to tell you got a bad MAF

P00to P0064) indicate a fault with that sensor. If the Osensor fails, it usually causes the engine to run rich leading to poor economy, pollution, and catalytic converter failure.

Check vacuum to voltage readings at the MAF and MAP sensors using your scanner. Check the MAP sensor hose for cracks or a broken vacuum hose.A faulty mass air flow sensor has a devastating effect on an engine. Subaru mass air flow sensors often have issues with performance.