GM Service Manual Online
For 1990-2009 cars only

DTC P0100, P0102, or P0103 LDK with Turbocharger

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 Descriptors

DTC P0100: Mass Air Flow (MAF) Sensor Circuit

DTC P0102: Mass Air Flow (MAF) Sensor Circuit Low Frequency

DTC P0103: Mass Air Flow (MAF) Sensor Circuit High Frequency

Diagnostic Fault Information

Circuit

Short to Ground

High Resistance

Open

Short to Voltage

Signal Performance

Ignition 1 Voltage

P0031, P0037, P0100, P0458

P0100

P0100

--

P0100

MAF Sensor Signal

P0100

P0100

P0100

P0100

P0101, P0102, P0103

Ground

--

P0100

P0100

--

P0100

Typical Scan Tool Data

MAF Sensor

Circuit

Short to Ground

Open

Short to Voltage

Operating Conditions: Engine running at various operating conditions

Parameter Normal Range: 1,700-12,500 Hz

Ignition 1 Voltage

65,535 Hz

65,535 Hz

--

MAF Sensor

65,535 Hz

65,535 Hz

65,535 Hz

Ground

--

65,535 Hz

--

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. The MAF/IAT sensor has the following circuits:

    • Ignition 1 voltage
    • MAF sensor ground
    • MAF sensor signal
    • IAT sensor signal
    • IAT low reference

The ECM applies 5V 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 frequency varies in a range of near 1,700 Hertz at idle to near 12,500 Hertz at maximum engine load.

Conditions for Running the DTCs

    • The engine is running.
    • The engine speed is greater than 300 RPM.
    • The ignition 1 voltage signal is greater than 10.5V.
    • The above conditions are met for greater than 1 second.
    • This DTC runs continuously within the enabling conditions.

Conditions for Setting the DTC

P0100

The ECM detects that the MAF Sensor parameter is equal to 0 Hz for greater than 0.5 second.

P0102

The ECM detects that the MAF Sensor parameter is less than 1035 Hz for greater than 0.5 second.

P0103

The ECM detects that the MAF Sensor parameter is greater than 15,152 Hz for greater than 0.5 second.

Action Taken When the DTC Sets

    • DTCs P0100, P0102, P0103 are Type B DTCs.
    • The ECM will disable boost control and limit the system to mechanical boost only, resulting in a substantial decrease in engine power.

Conditions for Clearing the MIL/DTC

DTCs P0100, P0102, P0103 are Type B DTCs.

Diagnostic Aids

    • The charge air cooler (CAC) is connected to the turbocharger and to the throttle body by flexible ductwork that requires the use of special high torque fastening clamps. These clamps cannot be substituted.
    • In order to prevent any type of air leak when servicing the dutctwork, the tightening specifications and proper positioning of the clamps is critical and must be strictly adhered to.
    • A steady or intermittent high resistance of 15Ω or greater on the ignition 1 voltage circuit will cause the MAF sensor signal to be increased by as much as 60 g/s.
    • 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

Connector End View Reference

Component Connector End Views

Description and Operation

    •  Turbocharger System Description
    •  Boost Control 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

For equivalent regional tools, refer to Special Tools.

Circuit/System Verification

  1. Engine operating at idle, observe the scan tool MAF Sensor parameter. The reading should be between 1,700-3,200 Hz.
  2. A wide open throttle (WOT) acceleration from a stop should cause the MAF sensor parameter on the scan tool to increase rapidly. This increase should be from 2-6 g/s at idle to greater than 200 g/s at the time of the 1-2 shift.
  3. 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 integrity of the entire air induction system including all turbocharger components by inspecting for the following conditions:
  2. • Loose or improper installation
    • Water intrusion
  3. Ignition OFF for 90 seconds, disconnect the harness connector at the B75B MAF/IAT sensor.
  4. Test for less than 5Ω between the ground circuit terminal B and ground.
  5. If greater than the specified range, test the ground circuit for an open/high resistance.
  6. Ignition ON, verify that a test lamp illuminates between the ignition circuit terminal C and ground.
  7. If the test lamp does not illuminate, test the ignition circuit for a short to ground or an open/high resistance.
  8. Ignition ON, test for 4.8-5.2V between the signal circuit terminal A and ground.
  9. 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.
  10. Ignition OFF, connect the red lead of the J 38522 to the signal circuit terminal A at the B75B MAF/IAT sensor harness connector. Connect the battery voltage supply to B+. Connect the black lead to ground.
  11. Set the J 38522 Signal switch to 5V, the Frequency switch to 5K, and the Duty Cycle switch to Normal.
  12. Engine Idling, observe the scan tool MAF Sensor parameter. The scan tool MAF Sensor parameter should be between 4,950-5,025 Hz.
  13. If the MAF Sensor parameter is not within the specified range, replace the K20 ECM.
  14. If all circuits test normal, test or replace the B75B MAF/IAT sensor.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

    •  Mass Airflow Sensor Replacement
    •  Control Module References for ECM replacement, setup, and programming