P0102
DTC P0102 or P0103 (Without Supercharger)
Diagnostic Instructions
* Perform the Diagnostic System Check - Vehicle Diagnostic System Check - Vehicle prior to using this diagnostic procedure.
* Review Strategy Based Diagnosis Strategy Based Diagnosis for an overview of the diagnostic approach.
* Diagnostic Procedure Instructions Diagnostic Procedure Instructions provides an overview of each diagnostic category.
DTC Descriptors
DTC P0102
- Mass Air Flow (MAF) Sensor Circuit Low Frequency
DTC P0103
- Mass Air Flow (MAF) Sensor Circuit High Frequency
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 ECM applies 5 V 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 within a range of near 2,000 Hertz at idle to near 9,500 Hertz at maximum engine load.
Conditions for Running the DTC
* The engine is running for greater than 1 s.
* The engine speed is greater than 300 RPM.
* The ignition 1 signal is greater than 9 V.
* The above conditions are met for greater than 1 s.
* These DTCs run continuously when the above conditions are met.
Conditions for Setting the DTC
P0102
The ECM detects that the MAF Sensor parameter is less than 1,500 Hz for greater than 5 s.
P0103
The ECM detects that the MAF Sensor parameter is greater than 14,500 Hz for greater than 5 s.
Action Taken When the DTC Sets
DTCs P0102 and P0103 are Type B DTCs.
Conditions for Clearing the MIL/DTC
DTCs P0102 and P0103 are Type B DTCs.
Diagnostic Aids
* Verify the integrity of the air induction system by inspecting for the following conditions:
- Any water intrusion in the induction system
- Any contamination or debris on the sensing elements of the MAF sensor
- Damaged components
* Verify that any electrical aftermarket devices are properly connected and grounded. Refer to Checking Aftermarket Accessories Checking Aftermarket Accessories.
Reference Information
Schematic Reference
Engine Controls Schematics (LS3) [1][2]Electrical DiagramsEngine Controls Schematics (LS9) [1][2]Electrical DiagramsEngine Controls Schematics (LS7) [1][2]Electrical Diagrams
Connector End View Reference
Component Connector End Views Folding Top 5 Bow Lowered Switch (CM7)
Electrical Information Reference
* Circuit Testing Circuit Testing
* Connector Repairs Connector Repairs
* Testing for Intermittent Conditions and Poor Connections Testing for Intermittent Conditions and Poor Connections
* Wiring Repairs Wiring Repairs
DTC Type Reference
Powertrain Diagnostic Trouble Code (DTC) Type Definitions Powertrain Diagnostic Trouble Code (DTC) Type Definitions
Scan Tool Reference
Control Module References Control Module References for scan tool information
Special Tools
J 38522 - Variable Signal Generator
For equivalent regional tools, refer to Special Tools Tools and Equipment.
Circuit/System Verification
1. Ignition ON.
2. Verify the scan tool MAF Sensor g/s parameter changes smoothly and gradually as the engine speed is increased and decreased while performing the actions listed below.
1. Engine idling
2. Perform the scan tool snapshot function.
3. Increase the engine speed slowly to 3,000 RPM and then back to idle.
4. Exit from the scan tool snapshot and review the data.
5. Observe the MAF Sensor parameter frame by frame with a scan tool.
• The MAF Sensor parameter does not change smoothly and gradually
Refer to Circuit/System Testing - step 1.
• The MAF Sensor parameter changes smoothly and gradually
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/Failure Records data.
4. Verify a DTC does not set.
• If any DTC sets
Refer to Diagnostic Trouble Code (DTC) List - Vehicle Diagnostic Trouble Code (DTC) List - Vehicle for further diagnosis.
• If no DTCs set
5. All OK
Circuit/System Testing
Note: You must perform the Circuit/System Verification before proceeding with Circuit/System Testing.
1. Ignition OFF and all vehicle systems OFF, disconnect the harness connector at the B75B mass air flow /intake air temperature sensor. It may take up to 2 minutes for all vehicle systems to power down.
2. Test for less than 2 ohms between the ground circuit terminal B and ground.
• If 2 ohms or greater
1. Ignition OFF.
2. Test for less than 2 ohms in the ground circuit end to end.
• If 2 ohms or greater, repair the open/high resistance in the circuit.
• If less than 2 ohms, repair the open/high resistance in the ground connection.
• If less than 2 ohms
3. Ignition ON, verify a test lamp illuminates between the ignition voltage circuit terminal C and ground.
• If the test lamp does not illuminate and the circuit fuse is good
1. Ignition OFF.
2. Test for less than 2 ohms in the ignition voltage circuit end to end.
• If 2 ohms or greater, repair the open/high resistance in the circuit.
• If less than 2 ohms, verify the fuse is not open and there is voltage at the fuse.
• If the test lamp does not illuminate and the circuit fuse is open
1. Ignition OFF.
2. Test for infinite resistance between the ignition voltage circuit and ground.
• If less than infinite resistance, repair the short to ground on the circuit.
• If infinite resistance
3. Test for greater than 2 ohms between the ignition voltage circuit terminal C and ground.
• If less than 2 ohms, repair the short to ground on the circuit.
• If greater than 2 ohms, test all the components connected to the circuit and repair or replace as necessary.
• If the test lamp illuminates
4. Ignition ON, test for 4.8-5.2 volts between the signal circuit terminal A and ground.
• If less than 4.8 V
1. Ignition OFF, disconnect the X2 harness connector at the K20 engine control module.
2. Test for infinite resistance between the signal circuit and ground.
• If less than infinite resistance, repair the short to ground on the circuit.
• If infinite resistance
3. Test for less than 2 ohms in the signal circuit end to end.
• If 2 ohms or greater, repair the open/high resistance in the circuit.
• If less than 2 ohms, replace the K20 engine control module.
• If greater than 5.2 V
1. Ignition OFF, disconnect the X2 harness connector at the K20 engine control module, ignition ON.
2. Test for less than 1 V between the signal circuit and ground.
• If 1 V or greater, repair the short to voltage on the circuit.
• If less than 1 V, replace the K20 engine control module.
• If between 4.8-5.2 V
5. Ignition OFF, connect the red lead of the J 38522 - Variable Speed Generator to the signal circuit terminal A at the harness connector. Connect the battery voltage supply to B+, and the black lead to ground.
6. Set the J 38522 - Variable Speed Generator to the following specifications.
* Signal switch to 5 V
* Frequency switch to 5 KHz
* Duty Cycle switch to Normal
7. Engine idling, observe the scan tool MAF Sensor parameter. The scan tool MAF Sensor parameter should be between 4,950-5,050 Hz.
• If not between 4,950-5,050 Hz.
If not between 4,950-5,050 Hz., replace the K20 engine control module.
• If between 4,950-5,050 Hz.
8. Test or replace the B75B mass air flow /intake air temperature sensor.
Repair Instructions
Perform the Diagnostic Repair Verification Verification Tests after completing the repair.
* Mass Airflow Sensor with Intake Air Temperature Sensor Replacement Service and Repair
* Control Module References Control Module References for engine control module replacement, programming, and setup