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Home >> Chevy Truck >> 2007 >> Express 3500 V8-6.6L DSL Turbo VIN 6 >> Repair and Diagnosis >> A L L Diagnostic Trouble Codes ( DTC ) >> Testing and Inspection >> P Code Charts >> P0102

P0102



DTC P0102 or P0103

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 provide an overview of each diagnostic category.

DTC Descriptors

DTC P0102
- Mass Air Flow (MAF) Sensor Circuit Low Voltage

DTC P0103
- Mass Air Flow (MAF) Sensor Circuit High Voltage

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 MAF/IAT sensor has the following circuits:

* A MAF sensor ignition 1 voltage circuit
* A MAF sensor ground circuit
* A MAF sensor signal circuit
* An IAT sensor signal circuit
* An IAT sensor low reference circuit

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 signal on the inlet airflow through the sensor bore. The frequency varies in a range depending on engine coolant temperature (ECT) sensor 1 of approximately 2,400 Hertz at idle to near 17,500 Hertz at maximum engine load.

Conditions for Running the DTC

P0102
* The engine is running for greater than 2 seconds.
* The engine speed is between 500-3,100 RPM.
* The above conditions are met for more than 3 seconds.
* This DTC runs continuously within the enabling conditions.

P0103
* The engine is running for greater than 2 seconds.
* The above conditions are met for greater than 3 seconds.
* This DTC runs continuously within the enabling conditions.

Conditions for Setting the DTC

P0102

The ECM detects that the MAF sensor is less than 3.6 g/s for greater than 3 seconds.

P0103

The ECM detects that the MAF sensor is greater than 527 g/s for greater than 3 seconds.

Action Taken When the DTC Sets

DTCs P0102 and P0103 are Type B DTCs.

Conditions for Clearing the DTC

DTCs P0102 and P0103 are Type B DTCs.

Diagnostic Aids

* 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 21-39 g/s at idle to greater than 380 g/s at the time of the 1-2 shift.
* For an intermittent problem, visually and physically inspect the exhaust gas recirculation (EGR) valve for a possible binding or sticking in the open position.
* Verify that any electrical aftermarket devices are properly connected and grounded. Refer to Checking Aftermarket Accessories in Diagnostic Aids. Component Tests and General Diagnostics

Circuit/System Verification

1. Verify that the following DTCs are not set: P003A, P0047, P0048, P0106, P0403, P0405, P0406, P046C, P02E2, P02E3, P02E7, P02E8, or P02E9.

• If any of the DTCs are set, Refer to Diagnostic Trouble Code (DTC) List - Vehicle Diagnostic Trouble Code Descriptions

2. Engine running at idle, observe the scan tool MAF Sensor parameter. The reading should be between 2,400-4,400 Hz depending on the ECT sensor 1.
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 Records data.

Circuit/System Testing

1. Verify the integrity of the entire air induction system by inspecting for the following conditions:

* Damaged components
* Loose or improper installation
* Restrictions or leaks in the air induction system
* Water intrusion
* In cold climates, inspect for any snow or ice build-up.

2. Ignition OFF, disconnect the harness connector at the MAF/IAT sensor.
3. Ignition OFF for 90 seconds, test for less than 5 ohms of resistance between the low reference circuit terminal 2 and ground.

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

4. Ignition ON, verify that a test lamp illuminates between the ignition 1 voltage circuit terminal 3 and ground.

• If the test lamp does not illuminate, test the ignition 1 voltage circuit for a short to ground or an open/high resistance.

5. Ignition ON, test for 4.8-5.2 volts between the MAF signal circuit and ground.

• If less than the specified range, test the MAF signal circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the ECM.
• If greater than the specified range, test the MAF signal circuit for a short to voltage. If the circuit tests normal, replace the ECM.

6. Remove the air inlet tube to the intake manifold.
7. Visually inspect the EGR valve and verify the valve is in the closed position.

• If the EGR valve is not in the closed position, replace the EGR valve.
• If the EGR valve inspection is normal, replace the MAF/IAT sensor.

8. If all circuits and the EGR valve test normal, test or replace the MAF sensor.

Component Testing

Important: You must perform the Circuit/System Testing in order to verify the integrity of the MAF sensor circuits before proceeding with the Component Testing.

To determine if the ECM can properly process the MAF sensor frequency signal, connect the J 38522 to the vehicle as follows:

1. Turn OFF the ignition.
2. Connect the battery voltage supply and ground the black lead.
3. Connect the red lead to the signal circuit terminal A of the MAF sensor.
4. Set the duty cycle switch to Normal.
5. Set the Frequency switch to 5 K.
6. Set the signal switch to 5 volts.
7. Start the engine, observe the MAF Sensor parameter for the correct range of 4,950-5,025 Hz.

• If the MAF Sensor parameter is not within the specified range, replace the ECM.
• If the MAF Sensor parameter is within the specified range, replace the MAF sensor.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

* Mass Airflow Sensor/Intake Air Temperature Sensor Replacement
* Exhaust Gas Recirculation Valve Replacement
* Control Module References for ECM replacement, setup, and programming Programming and Relearning Verification Tests
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