P0101 Mass or volume air flow circuit range or performance
- System
- Powertrain - engine and transmission
What P0101 means
"Mass or volume air flow circuit range or performance" is about a reading that was present but did not fit. The computer has a figure for how much air is entering the engine, and it compares that figure against what the engine's speed, load and throttle position say it should be; this code is filed when the two do not agree. "Range or performance" is the standard wording for exactly that: a reading inside its electrical limits but outside what the rest of the readings imply.
This is a standard code. It means the same thing on every make of vehicle.
What the program shows for P0101
Air flow sits on the Dashboard next to Manifold pressure, Engine load, Absolute load, Throttle position and Engine speed, which are the readings the comparison is made against. Over a recorded drive the Analysis screen plots fuel trim against air flow and says whether the air flow and pressure readings agree with each other.
The Dashboard shows Short fuel trim and Long fuel trim, Air flow, Manifold pressure, Intake air temp, Coolant temp, Throttle position, Accelerator pedal, Air/fuel ratio, O2 sensor (rear), O2 sensor current and whether the Fuel system is in closed loop. Record a drive and the Analysis screen gives the total correction At idle, Fuel trim against air flow, and whether the air flow and pressure sensors agree; the Full scan's On-board self-tests list the Oxygen sensor results by bank and sensor. Record before and after a repair and Compare shows the change in short, long and total trim at idle plus which codes are Gone, New or Still there.
See how the program shows a code →