P0101 trouble code Mass or Volume Air Flow Circuit Low Input
What is a P0101 trouble code
A P0101 Mass Airflow (MAF) Circuit Problem relates to a problem with the circuit servicing the mass airflow sensor. Common codes are P0101, P0102, P0103 and P0104. However, a P0101 code means
the signal the computer is receiving is too far below the expected value.
What causes a P0101 trouble code
The single most common cause of a P0101 trouble code is an intake air leak (near the MAF sensor). This can be caused by a tear in the flexible air duct or a loose hose clamp. Since the engine is always sucking air from the air filter box, any air that doesn’t get metered through the MAF will cause the computer to see a lean condition which it will try to correct by adjusting fuel. If it can’t and the MAF reading stays low, the PCM will set the check engine light and store this code.
Other causes of a P0101 trouble code
• Fuse blown to MAF
• Wiring harness issues that cuts power to MAF
• MAF sensor disconnected
• MAF circuit signal wire has an open to between the sensor and PCM
• PWR GND open to MAF sensor
• MAF reference signal return circuit is open to PCM
• MAF circuit shorted to GND
• A closed [throttle indication throttle position (TP) sensor system]
• Damaged MAF sensor
• Damaged PCM
How to diagnose a P0101 trouble code
The sensor receives power from the fuse and ground from the PCM. Depending on the type of MAF sensor, it can alter the returning voltage or generate a digital square wave back to the computer.
A P0101 code means the computer has detected a value returning from the MAF that is outside the allowable range or of low value. The computer determines that it is a low value by comparing the reading to inputs from other sensors.
Is the P0101 trouble code serious?
The P0101 trouble code won’t prevent your vehicle from starting or driving, but if the MAF isn’t working properly, you’ll get poor gas mileage and low power.
© 2012 Rick Muscoplat
Posted on by Rick Muscoplat