P1101

DTC P0101 or P1101

Diagnostic Instructions

* Perform the Diagnostic System Check - Vehicle (Initial Inspection and Diagnostic Overview) prior to using this diagnostic procedure.
* Review Strategy Based Diagnosis (Initial Inspection and Diagnostic Overview) for an overview of the diagnostic approach.
* Diagnostic Procedure Instructions (Initial Inspection and Diagnostic Overview)provides an overview of each diagnostic category.



DTC Descriptors
DTC P0101
- Mass Air Flow (MAF) Sensor Performance

DTC P1101
- Intake Air Flow System 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 MAF sensor used on this engine is a voltage based sensor. The greater the airflow, the greater the voltage signal. The engine control module (ECM) uses the MAF sensor signal to provide the correct fuel delivery for all engine speeds and loads. The MAF/IAT sensor has the following circuits:

* Ignition 1 voltage circuit
* A shared MAF/IAT low reference circuit
* MAF sensor signal circuit
* IAT sensor signal circuit


The purpose of this diagnostic is to analyze the performance of the MAF sensor by comparing the measured airflow to 2 distinct models when the following operating conditions are met:

* At engine start with Closed Loop inactive.
* Engine running when Closed Loop becomes active.



Conditions for Running the DTC


P0101
* The barometric pressure (BARO) is greater than 69 kPa.
* Closed Loop is active.
* The engine is running for greater than 5 seconds.
* The engine speed is between 800-6496 RPM.
* The ignition 1 voltage is greater than 10 volts.
* The throttle position (TP) is between 5-85 percent.
* This DTC runs continuously within the enabling conditions.



Conditions for Running the DTC


P01101
* The barometric pressure (BARO) is greater than 69 kPa.
* Closed Loop is inactive.
* The engine is cranking or running.
* The ignition 1 voltage is greater than 10 volts.
* The throttle actuator control (TAC) power stage is active.
* This DTC runs continuously within the enabling conditions.



Conditions for Setting the DTC


P0101
* The ECM detects that the measured MAF is not within a calibrated range of the model for greater than 2 seconds.
AND
* The ECM detects a significant error, plus or minus in the fuel trim.


P1101

The ECM detects that the measured MAF is not within a calibrated range of the model for greater than 2 seconds.


Action Taken When the DTC Sets

DTCs P0101 and P1101 are Type B DTCs.


Conditions for Clearing the MIL/DTC

DTCs P0101 and P1101 are Type B DTCs.


Diagnostic Aids

* Use a solution of dish soap and water in a spray bottle to pinpoint any suspected air leaks in the induction system.
* Certain types of contaminants on the MAF sensor heating elements act as a heat insulator, which will impair the response of the sensor to airflow changes. This condition will affect the Fuel Trim adaptation value.
* At ignition ON, engine OFF, a small amount of voltage will display on the scan tool MAF sensor parameter. This is due to the heat that is generated by the MAF sensor heating elements.
* Depending on the current ambient temperature, and the vehicle operating conditions, a MAF sensor signal circuit that is shorted to the IAT signal circuit will increase or decrease the MAF sensor signal that is interpreted by the ECM. Additionally it may cause a rapid fluctuation in the IAT Sensor parameter.



Reference Information
Schematic Reference

Engine Controls Schematics (Electrical Diagrams)
Connector End View Reference

Component Connector End Views (Connector Views)
Electrical Information Reference

* Circuit Testing (Component Tests and General Diagnostics)
* Connector Repairs (Component Tests and General Diagnostics)
* Testing for Intermittent Conditions and Poor Connections (Component Tests and General Diagnostics)
* Wiring Repairs (Component Tests and General Diagnostics)

DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions (Diagnostic Trouble Code Descriptions)
Scan Tool Reference

Control Module References (Programming and Relearning)for scan tool information


Circuit/System Verification

1. Verify that restrictions do not exist in the exhaust system. Refer to Restricted Exhaust (Restricted Exhaust) .
2. Ignition OFF for 90 seconds, determine the current vehicle testing altitude.
3. Ignition ON, engine OFF, observe the scan tool BARO Sensor parameter. Compare the parameter to the Altitude Versus Barometric Pressure (Altitude Versus Barometric Pressure) table. The parameter should be within the specified range indicated in the table.

• If the parameter is not within range, refer to DTC P2227, P2228, or P2229 (P2227) .

4. A wide open throttle (WOT) acceleration from a stop should cause the MAF sensor parameter on the scan tool to increase rapidly.
5. 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. Ignition OFF, verify the integrity of the entire air induction system by inspecting for the following conditions:

* Any damaged components, including the throttle body (TB)
* Loose or improper installation
* An air flow restriction
* Vacuum leaks
* Improperly connected vacuum hoses
* In cold climates, inspect for any snow or ice buildup
* Inspect the MAF sensor elements for contamination

2. Disconnect the harness connector at the MAF/IAT sensor.
3. Ignition OFF for 90 seconds, test for less than 5.0 ohms between the low reference circuit terminal 1 and ground.

• If greater than the specified range, test the low reference circuit for an open/high resistance.

4. Ignition ON, verify that a test lamp illuminates between the ignition circuit terminal 4 and ground.

• If the test lamp does not illuminate, test the ignition circuit for a short to ground or an open/high resistance.

5. Verify the scan tool MAF Sensor parameter is less than 0.50 volt.

• If greater than the specified range, test the signal circuit terminal 3 for a short to voltage. If the circuit tests normal, replace the ECM.

6. Ignition ON, connect a test lamp between B+ and the signal circuit terminal 3.
7. Verify the scan tool MAF Sensor parameter is greater than 4.3 volts.

• 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 ECM.

8. If the circuits test normal, replace the MAF sensor.



Repair Instructions

Perform the Diagnostic Repair Verification (Verification Tests) after completing the diagnostic procedure.

* Mass Airflow Sensor Replacement (Service and Repair)
* Control Module References (Programming and Relearning)for ECM replacement, setup, and programming