P0101
DTC P0101
Diagnostic Instructions
* Perform the Diagnostic System Check - Vehicle (Diagnostic System Check - Vehicle) prior to using this diagnostic procedure.
* Review Strategy Based Diagnosis (Strategy Based Diagnosis) for an overview of the diagnostic approach.
* Diagnostic Procedure Instructions (Diagnostic Procedure Instructions)provides an overview of each diagnostic category.
DTC Descriptor
DTC P0101 00
- Mass Air Flow (MAF) Sensor Performance
Diagnostic Fault Information
Typical Scan Tool Data
Circuit/System Description
The mass air flow (MAF) sensor is integrated with the intake 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. A small quantity of air entering the engine indicates a deceleration or idle condition. A large quantity of air entering the engine indicates an acceleration or 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.
Conditions for Running the DTC
* DTCs P0102 00, P0103 00, P0106 00, P0107 00, P0108 00, P0112 00, P0113 00, P0117 00, P0118 00, P0335 00, P0336 00 are not set.
* The engine speed is between 400-6 500 RPM.
* The IAT sensor is between -20 to +125°C (-4 to +257°F).
* The engine coolant temperature (ECT) sensor is between 70-125°C (158-257°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
DTCs P0101 00 is a Type B DTC.
Conditions for Clearing the DTC
DTCs P0101 00 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 coils
* Any solenoids
* Any relays
* Any motors
* 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.
* A MAF sensor that is installed incorrectly may set this DTC.
Reference Information
Schematic Reference
Engine Controls Schematics ([1][2]Electrical Diagrams)
Connector End View Reference
Component Connector End Views (Connector End Views By Name)
Electrical Information Reference
* Circuit Testing (Circuit Testing)
* Connector Repairs (Connector Repairs)
* Testing for Intermittent Conditions and Poor Connections (Testing for Intermittent Conditions and Poor Connections)
* Wiring Repairs (Wiring Repairs)
DTC Type Reference
Powertrain Diagnostic Trouble Code (DTC) Type Definitions (Powertrain Diagnostic Trouble Code (DTC) Type Definitions)
Scan Tool Reference
Control Module References (Programming and Relearning)for scan tool information
Special Tools
EL 38522 - Variable Signal Generator
For equivalent regional tools, refer to Special Tools (Tools and Equipment).
Circuit/System Verification
1. Engine idling, observe the DTC information with a scan tool. DTC P0101 00 should not set.
2. Verify the scan tool MAF Sensor Hz parameter is between 1 700-2 100 Hz.
3. Operate the vehicle within the conditions for running the DTC. 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:
* An engine vacuum leak
* An air leak in the intake air duct between the mass air flow (MAF) sensor and the throttle body
* Objects that block the MAF sensor air inlet
* An air filter element that is restricted
* 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 B75B Mass Air Flow/Intake Air Temperature Sensor.
3. Ignition OFF for 90 s, test for less than 5 ohm between the ground circuit terminal 2 and ground.
• If greater than the specified range, test the ground circuit for an open/high resistance.
4. Ignition ON, test for B+ between the ignition voltage circuit terminal 4 and ground.
• If less than the specified range, test the ignition voltage circuit for a short to ground or an open/high resistance.
5. Ignition ON, test for 4.8-5.2 V between the signal circuit terminal 5 and ground.
• 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 Engine Control Module.
• If greater than the specified range, test the signal circuit for a short to voltage. If the circuit tests normal, replace the K20 Engine Control Module.
6. Ignition OFF, connect the red lead of the EL 38522 - Variable Signal Generator to the signal circuit terminal 5 at the B75B Mass Air Flow/Intake Air Temperature Sensor harness connector. Connect the battery voltage supply to the B+, and ground the black lead.
7. Set the EL 38522 - Variable Signal Generator to the following specifications signal switch to 5 V, the Frequency switch to 5 K, and the duty cycle switch to normal.
* Signal switch to 5 V
* Frequency switch to 5 KHz
Note: The engine will run rough and may stall.
* Duty Cycle switch to Normal
8. Engine idling, observe the scan tool MAF Sensor Hz parameter. The scan tool MAF Sensor parameter should be between 4 950-5 025 Hz.
• If the MAF Sensor parameter is not within the specified range, replace the K20 Engine Control Module.
9. If all other circuits test normal, test or replace the B75B Mass Air Flow/Intake Air Temperature Sensor.
Repair Instructions
Perform the Diagnostic Repair Verification (Verification Tests) after completing the repair.
Control Module References (Programming and Relearning)for ECM replacement, setup, and programming