For 1990-2009 cars

### 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 64: Mass Air Flow Sensor Slip Detected
DTC P0102 12: Mass Air Flow Sensor Circuit Low Low Input
DTC P0103 11: Mass Air Flow Sensor Circuit High High Input

### Diagnostic Fault Information

Circuit | Short to Ground | Open/High Resistance | Short to Voltage | Signal Performance
--- | --- | --- | --- | ---
Ignition Voltage | P0102 12 | P0102 12 | -- | P0101 64
Signal | P0102 12 | P0102 12 | P0103 11 | P0101 64
Ground | -- | P0102 12 | -- | P0101 64

### 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

• | The ignition is ON

• | The battery voltage is greater than 8.5 V

• | The engine speed is between 1 000-4 000 RPM

### Conditions for Setting the DTC

The ECM detects the MAF signal circuit is open, shorted to ground, or shorted to a voltage for less than 1 second.

### Action Taken When the DTC Sets

DTCs P0101, P0102 and P0103 are Type B DTCs.

### Conditions for Clearing the DTC

DTCs P0101, P0102 and P0103 are Type B DTCs.

### Diagnostic Aids

• | Inspect the harness of the MAF sensor to verify that it is not routed too close to the following components:

- | 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.

### Reference Information

#### Schematic Reference

Engine Controls Schematics

#### Connector End View Reference

Component Connector End Views

#### 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

### Circuit/System Verification

1. Engine running for 60 s, observe the DTC information with a scan tool. DTCs P0101, P0102 and P0103 should not set.
2. 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,disconnect the harness connector at the B75B Mass Air Flow (MAF)/Intake Air Temperature (IAT) Sensor.
2. Test for less than 5 Ω between the ground circuit terminal 2 and ground.

⇒ | If greater than the specified range, test the ground circuit for an open/high resistance.

3. Ignition ON, test for greater than 11 V voltage between the ignition circuit terminal 4 and ground.

⇒ | If less than the specified range, test the ignition circuit for a short to ground or an open/high resistance. If the circuit tests normal and the ignition circuit fuse is open, test all the components connected to the ignition circuit and replace as necessary.

4. 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 an open/high resistance or a short to ground. If the circuit tests normal, replace the K20 Engine Control Module (ECM).

⇒ | 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 (ECM).

5. If all circuits test normal, replace the B75B Mass Air Flow (MAF)/Intake Air Temperature (IAT) Sensor.

### Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

• | Mass Airflow Sensor with Intake Air Temperature Sensor Replacement

• | Control Module References for engine control module replacement, setup, and programming