P0101
Mass Air Flow (MAF) Circuit Range/Performance
The MAF sensor reading does not match expected values based on engine load and RPM.
The ECM compares the MAF sensor reading against calculated airflow based on throttle position, RPM, and other sensor inputs. When the actual reading deviates significantly from the expected value, this code is triggered. This often indicates a sensor that is reading but not accurately.
Symptoms
Common Causes
Dirty MAF sensor element
HIGHContamination causes inaccurate readings that are within electrical range but wrong for actual airflow.
Vacuum leak
HIGHAir entering after the MAF sensor is not measured, causing a lean condition.
Restricted air filter
MEDIUMA severely clogged filter restricts airflow below normal range.
Exhaust leak before O2 sensor
LOWCan confuse the ECM fuel trim calculations.
Step-by-Step Diagnosis
Check air filter
easyInspect the engine air filter for excessive dirt or restriction. Replace if needed.
Clean or test MAF sensor
mediumClean with MAF cleaner. Monitor live data: at idle a typical MAF reads 2-7 g/s; at 2500 RPM expect 15-25 g/s.
Smoke test for leaks
hardPerform a smoke test on the intake system to find any vacuum or air leaks downstream of the MAF.
Frequently Asked Questions
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