P0101

DTC P0101: Mass Air Flow (MAF) Sensor Performance

Wiring Diagram:

Circuit Description
The DTC P0101 checks the accuracy of the Mass Air Flow sensor signal. The MAF sensor measures the amount of air which passes through the sensor in a given amount of time. The Engine Control Module (ECM) uses this information to determine the operating requirements of the engine in order to control the fuel delivery. The ECM calculates the engines fuel requirements by monitoring the current flow on the signal wire from the MAF sensor. When the volume of air entering the MAF sensor increases, the current flow sensed by the ECM from the MAF sensor also increases. When the air flow decreases, the current sensed by the ECM also decreases.

Conditions for Setting the DTC
- Mass air flow deviations catalyst heating phase are greater than pre-determined values.

Action Taken When the DTC Sets
- The Malfunction Indicator Lamp (MIL) will illuminate.
- The ECM will record operating conditions at the time the diagnostic fail. This information will be stored in the Freeze Frame and Failure Records buffers.
- A history DTC is stored.

Conditions for Clearing the MIL/DTC
- The MIL will turn OFF at the end of 3 consecutive validation cycles in which the diagnostic runs without a fault.
- A history DTC will clear after 40 warm up cycles without a fault.
- DTC(s) can be cleared by using the scan tool.

Diagnostic Aids
Check for any of the following conditions:
- A skewed or malfunctioning Manifold Absolute Pressure (MAP) sensor. A faulty MAP sensor circuit can cause the ECM to incorrectly calculate the predicted Mass Air Flow value.
- A leak in the air inlet system or intake manifold.
- A misrouted wiring harness. Inspect the MAF sensor harness to ensure that the harness is not routed too close to high voltage or high amperage circuits.
- A damaged wiring harness. Inspect the wiring harness for damage. If the harness appears to be OK, observe the scan tool while moving the connectors and the wiring harnesses related to the MAF sensor. A change in the display will indicate the location of the fault.
- A plugged intake air duct or a dirty air filter element.

An intermittent malfunction may be caused by a fault in the MAF sensor circuit. Inspect the wiring harness and components for an intermittent condition. If DTC P0101 cannot be duplicated, the information included in the Freeze Frame data can be useful in determining the vehicle operating conditions when the DTC was first set.

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DTC Troubleshooting