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For 1990-2009 cars only
Makes 🢒 Buick 🢒 2009 🢒 Enclave 🢒 Diagnostic Navigation 🢒 Vehicle Diagnostic Information 🢒 DTC P0101

Diagnostic Instructions
    • Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure.
    • Review Strategy Based Diagnosis for an overview of the diagnostic approach.
    •  Diagnostic Procedure Instructions provides an overview of each diagnostic category.

DTC Descriptor

DTC P0101: Mass Air Flow (MAF) Sensor Circuit Performance

Diagnostic Fault Information

Circuit

Short to Ground

High Resistance

Open

Short to Voltage

Signal Performance

Ignition Voltage

P0100

P0100

P0100

--

P0101

MAF Sensor Signal

P0100

P0102

P0100

P0102

P0101

Low Reference

--

P0102

P0100

--

P0101

Circuit/System Description

The mass air flow (MAF) sensor is located in the air intake duct. The MAF sensor is an airflow meter that measures the amount of air that enters the engine. The MAF sensor uses a hot film that is cooled by air flowing past the sensing film as air enters the engine. The amount of cooling is proportional to the amount of the air flow. As the air flow increases, more current is required in order to maintain the hot film at a constant temperature. The engine control module (ECM) uses the MAF sensor in order to provide the correct fuel delivery for all operating conditions.

Conditions for Running the DTC
    • Before the ECM can report DTC P0101 failed, DTCs P0010, P0011, P0013, P0014, P0020, P0021, P0023, P0024, P0100, P0102, P0103, P0111, P0112, P0113, P0121, P0122, P0123, P0221, P0222, P0223, P0335, P0336, P0338, P2088, P2089, P2090, P2091, P2092, P2093, P2094, P2095, P2227, P2228, or P2229 must run and pass.
    • DTC P2176 is not set.
    • The engine is operating for greater than 1 second.
    • The MAF signal is greater than 0.00 g/s and steady.
    • The ignition voltage is greater than 10 volts.
    • The engine coolant temperature (ECT) is warmer than 10°C (50°F).
    • The long term fuel trim is enabled.
    • The throttle angle is steady +/-2 percent.
    • The ECM detects greater than 150 revolutions of the crankshaft.
    • DTC P0101 runs continuously once the above conditions are met for greater than 2 seconds.

Conditions for Setting the DTC
    • The ECM detects that the MAF sensor signal is greater or less than the calculated air flow based on engine load and engine speed.
        OR
    • The ECM detects that the MAF sensor signal is greater or less than the calculated air flow, and The ECM detects a significant error in the long term fuel trim at cruising speed.

Action Taken When the DTC Sets

DTC P0101 is a Type B DTC.

Conditions for Clearing the DTC

DTC P0101 is a Type B DTC.

Diagnostic Aids
    • Inspect the harness of the MAF sensor to verify that it is not routed too close to the following components:
       - The secondary ignition wires or coils
       - Any solenoids
       - Any relays
       - Any motors
    • Inspect the hydro-carbon (HC) absorber in the air cleaner assembly for ruptures that would leak charcoal into the air intake, contaminating the sensing element.
    • Inspect for any contamination, water intrusion, or debris on the sensing elements of the MAF sensor. If debris is present, clean the sensor. If the sensor cannot be cleaned, replace the sensor.
    • A high resistance may cause a driveability concern before this DTC sets.

Reference Information

Schematic Reference

Engine Controls Schematics

Connector End View Reference

Component Connector End Views

Description and Operation

Air Intake System Description

Electrical Information Reference

    •  Circuit Testing
    •  Connector Repairs
    •  Testing for Intermittent Conditions and Poor Connections
    •  Wiring Repairs

DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

Scan Tool Reference

Control Module References for scan tool information

Special Tools

J 38522 Variable Signal Generator

Circuit/System Verification
  1. Engine idling for 1 minute, observe the DTC information with a scan tool. DTC P0101 should not set.
  2. Operate the vehicle within the Conditions for Running the DTC to verify the DTC does not reset. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records data.

Circuit/System Testing
  1. Inspect for the following conditions:
    2. • An engine vacuum leak
    • An air leak in the intake air duct between the mass air flow (MAF) sensor and the throttle body
    • A plugged or collapsed intake air duct
    • Objects that block the MAF sensor air inlet
    • An air filter element that is restricted
    • The hydro-carbon absorber in the air cleaner assembly for ruptures or deterioration, if equipped.
    • A restricted throttle plate or for carbon build-up around the throttle plate
    • An unseated engine oil dip stick
    • A loose or missing engine oil fill cap
    • An over filled crankcase
    ⇒If you find any of the above conditions, repair as necessary.
  2. Ignition OFF, disconnect the harness connector at the MAF sensor.
  3. Ignition OFF, test for less than 5 Ω between the ground circuit terminal C and the battery ground.
    4. ⇒If greater than the specified range, test the ground circuit for an open/high resistance.

    Caution: Do NOT use the low reference circuit in the component harness connector for this test. Damage to the control module may occur due to excessive current draw.

  4. Ignition ON, load test the ignition circuit for B+ between terminal B and ground.
    5. ⇒If less than the specified value, test the ignition circuit for an open/high resistance.
  5. Test for 4.8-5.2 V between the signal circuit terminal A and the ground circuit terminal C.
    6. ⇒If less than the specified range, test the signal circuit for an open/high resistance or a short to ground. If the circuit/connections test normal, replace the ECM.
    ⇒If greater than the specified range, test the signal circuit for a short to voltage. If the circuit/connections test normal, replace the ECM.
  6. Ignition OFF, connect the red lead of the J 38522 to the signal circuit terminal A at the MAF/IAT sensor harness connector. Connect the battery voltage supply to B+, and ground the black lead.
  7. Set the J 38522 Signal switch to 5 V, the Frequency switch to 5K, and the Duty Cycle switch to Normal.
  8. Ignition ON, observe the scan tool MAF Sensor frequency parameter. The parameter should be between 4,950-5,025 Hz.
    9. ⇒If the parameter is not within the specified range, replace the ECM.
  9. If all circuits/connections test normal, replace the MAF sensor.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

    •  Mass Airflow Sensor/Intake Air Temperature Sensor Replacement
    •  Control Module References for engine control module replacement, setup, and programming