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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 Performance

Diagnostic Fault Information

Circuit

Short to Ground

High Resistance

Open

Short to Voltage

Signal Performance

Ignition Voltage

P0102, P121B

P0101, P0102

P0102

P0690

P0101

MAF Sensor Signal

P0102

P0102

P0101, P0102

P0102

P0101, P1101

MAF Control

P0101, P121B

P0101, P0102

P0101, P0102

P0101, P0102, P121C

-

Typical Scan Tool Data

MAF Sensor

Circuit

Short to Ground

Open

Short to Voltage

Operating Conditions: Vehicle ON, normal operating temperature and engine speed between 1,375 and 1,425 RPM Parameter Normal Range: 1,800-2,400 Hz

Ignition Voltage

0 Hz

0 Hz

-

MAF Sensor Signal

0 Hz

0 Hz

0 Hz

MAF Control

-

0 Hz

-

Circuit/System Description

The mass air flow (MAF) sensor is integrated with the inlet air temperature (IAT) sensor. The MAF sensor is an air flow meter that measures the amount of air entering the engine. The engine control module (ECM) uses the MAF sensor signal to provide the correct fuel delivery for all engine speeds and loads. The air flow and engine speed are very dependent on the battery pack state of charge. A small quantity of air entering the engine indicates a low load condition. A large quantity of air entering the engine indicates a high load condition.

The ECM applies 5 volts to the MAF sensor on the MAF sensor signal circuit. The sensor uses the voltage to produce a frequency based on the inlet air flow through the sensor bore.

The MAF sensor is supplied power through the powertrain relay and a fuse. The ECM enables the MAF sensor only during engine run mode by grounding the MAF control circuit via a solid state devise called a driver. The driver is equipped with a feedback circuit that is pulled-up to a voltage. The ECM monitors the status of the driver. If the ECM detects an incorrect voltage for the commanded state of the driver, a MAF sensor supply voltage low side driver control circuit DTC is set.

Conditions for Running the DTC

    • DTCs P0102, P0103, P0107, P0108, P0111, P0112, P0113, P0114, P0116, P0117, P0118, P0119, P0128, P0335, and P0336 are not set.
    • The engine speed is between 500 and 8,000 RPM.
    • The IAT Sensor is between -20 and +125°C (-4 and +257°F).
    • The ECT Sensor is between -7 and +125°C (+19 and +257°F).
    • The DTC runs continuously when the above conditions are met.

Conditions for Setting the DTC

The ECM detects that the MAF sensor signal is not within a predetermined range of the calculated MAF value.

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 ignition coil module
       - Any solenoids
       - Any relays
       - Any motors
    • Any type of contamination on the MAF sensor heating elements will degrade the proper operation of the sensor. Certain types of contaminants act as a heat insulator, which will impair the response of the sensor to airflow changes. Water or snow can create the opposite effect, and cause the signal to increase rapidly. 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.
    • Certain aftermarket air filters may cause this DTC to set.
    • Certain aftermarket air induction systems may cause this DTC to set.
    • Modifications to the air induction system may cause this DTC to set.

Reference Information

Schematic Reference

Engine Controls Schematics

Connector End View Reference

Component Connector End Views

Description and Operation

Hybrid Modes of Operation 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.

For equivalent regional tools, refer to Special Tools : Diagnostic Tools .

Circuit/System Verification

    Note: To ensure a proper engine load, this diagnostic should be performed when the Hybrid/EV Battery Pack Charge Remaning parameter is at least 40%.

  1. Observe the DTC information with a scan tool. Verify that DTC P121B and P121C are not set.
  2. If any of the DTCs are set, refer to DTC P121B or P121C .
  3. Vehicle ON, engine speed between 1,375 and 1,425 RPM, normal operating temperature. Verify the scan tool MAF Sensor parameter is between 1,800 and 2,400 Hz.
  4. 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. Verify the following conditions do not exist:
  2. • A dirty, restricted, or deteriorating air filter element
    • A leaking, loose, or cracked PCV pipe or seal
    • A restricted or collapsed air inlet duct
    • A misaligned, leaking, or damaged air inlet duct
    • Any objects blocking the air inlet probe of the B75B mass air flow/inlet air temperature sensor
    • Any contamination or debris on the sensing elements in the probe of the B75B mass air flow/inlet air temperature sensor
    • A cracked, damaged, or leaking B75B mass air flow/inlet air temperature sensor housing
    • Any water intrusion in the induction system
    • Any snow or ice build-up at the air cleaner or B75B mass air flow/inlet air temperature sensor in cold climates
    • Any vacuum leak
    • A B74 MAP sensor seal that is leaking, missing, or damaged
    • Q38 Throttle body for dirt, debris, and coking. Refer to Throttle Body Inspection and Cleaning .
    • A damaged Q38 throttle body blade or shaft
    • Missing, restricted, or leaking exhaust components. Refer to Symptoms - Engine Exhaust .
    If you find any of the above conditions, repair as necessary.
  3. Vehicle OFF, disconnect the harness connector at the B75B mass air flow/inlet air temperature sensor.
  4. Vehicle in Service Mode, test for 4.8-5.2 V between the signal circuit terminal 5 and ground.
  5. If less than the specified range, test the signal circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the K20 ECM.
    If greater than the specified range, test the signal circuit for a short to voltage. If the circuit tests normal, replace the K20 ECM.
  6. Verify that a test lamp illuminates between the ignition voltage circuit terminal 4 and ground.
  7. If the test lamp does not illuminate, test the ignition voltage circuit for a short to ground or an open/high resistance. If the circuit tests normal and the ignition voltage circuit fuse is open, test or replace the components on the ignition voltage circuit.
  8. Connect the test lamp between the MAF control circuit terminal 2 and the ignition voltage circuit terminal 4.
  9. Vehicle in Service Mode, command the MAF Sensor Supply Voltage Low Side Driver ON and OFF with a scan tool. The test lamp should turn ON and OFF when changing between the commanded states.
  10. If the test lamp is always ON, test the control circuit for a short to ground. If the circuit tests normal, replace the K20 ECM.
    If the test lamp is always OFF, test the control circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the K20 ECM.
  11. Vehicle OFF, connect the red lead of the J 38522 to the signal circuit terminal 5 at the harness connector. Connect the battery voltage supply to B+, and the black lead to ground.
  12. Set the J 38522 to the following specifications.
  13. • Signal switch to 5 V
    • Frequency switch to 5 KHz
    • Duty Cycle switch to Normal

    Note: The engine may run rough and stall.

  14. Vehicle ON, engine running, observe the scan tool MAF Sensor Hz parameter. The parameter should be between 4,950 and 5,025 Hz.
  15. If not within the specified range, replace the K20 ECM.
  16. If all circuits test normal, test or replace the B75B mass air flow/intake air temperature sensor.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

    •  Air Cleaner Element Replacement
    •  Mass Airflow Sensor with Inlet Air Temperature Sensor Replacement
    •  Throttle Body Assembly Replacement
    • Control Module References for ECM replacement, setup, and programming
   


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