Diagnostic Instructions
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 1 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, greater 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 P0100, P0102, P0103, P0111, P0112, P0113, P0121, P0122, P0123, P0221, P0222, P0223, P0335, P0336, and P0338 must run and pass. |
| • | The engine is operating for greater than 1 second. |
| • | The MAF sensor signal is greater than 1.4 grams per second. |
| • | The ignition voltage is greater than 11 volts. |
| • | The engine coolant temperature (ECT) is greater than 10°C (50°F). |
| • | The ECM detects greater than 150 revolutions of the crankshaft. |
| • | DTC P0101 runs continuously once the above conditions are met. |
Conditions for Setting the DTC
| • | The ECM detects that the MAF sensor signal is less than 0.14 g/s or greater than 278 g/s. |
| • | The condition exists for 4 seconds or for a cumulative of 30 seconds. |
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 in order to verify that it is not routed too close to the following components: |
| - | The secondary ignition wires or coils |
| • | Inspect the hydro-carbon (HC) filter 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
DTC Type Reference
Powertrain Diagnostic Trouble Code (DTC) Type Definitions
Scan Tool Reference
Control Module References for scan tool information
Circuit/System Verification
- Engine idling for 1 minute, observe the scan tool DTC information. DTC P0101 should not set.
- 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 are captured in the Freeze Frame/Failure Records Data List.
Circuit/System Testing
- Inspect for the following conditions:
| • | 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. |
| • | 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. |
- Ignition OFF, disconnect the harness connector at the MAF sensor.
- Ignition OFF, test for less than 5 Ω between the ground circuit terminal C and the battery ground.
| ⇒ | 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.
- Ignition ON, load test the ignition circuit for B+ between terminal B and ground.
| ⇒ | If less than the specified value, test the ignition circuit for an open/high resistance. |
- Test for 4.8-5.2 V between the signal circuit terminal A and the ground circuit terminal C.
| ⇒ | 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. |
- 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.
- Set the
J 38522
Signal switch to 5 V, the Frequency switch to 5K, and the Duty Cycle switch to Normal.
- Ignition ON, observe the scan tool MAF Sensor frequency parameter. The parameter should be between 4,950-5,025 Hz.
| ⇒ | If the parameter is not within the specified range, replace the ECM. |
- If all circuits/connections test normal, replace the MAF sensor.
Repair Instructions
Perform the
Diagnostic Repair Verification after completing the diagnostic procedure.
