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 P0102: Mass Air Flow (MAF) Sensor Circuit Low VoltageDTC P0103: Mass Air Flow (MAF) Sensor Circuit High Voltage
Diagnostic Fault Information
Circuit | Short to Ground | High Resistance | Open | Short to Voltage | Signal Performance |
|---|---|---|---|---|---|
Ignition 1 Voltage | P0102 | P0101 | P0102 | U1041, P0504 | P0101 |
MAF Sensor Signal | P0102 | P0101 | P0102 | P0101, P0103, P0401 | P0101 |
Ground | -- | P0101 | P0103 | -- | P0101 |
Typical Scan Tool Data
Circuit | Short to Ground | Open | Short to Voltage |
|---|---|---|---|
Parameter Normal Range: Varies 30-40 g/s at hot idle | |||
12-Volt Reference | 0 Volts, 0 g/s | 0 Volts, 0 g/s | -- |
MAF Sensor Signal | 0 Volts, 0 g/s | 0 Volts, 0 g/s | 4.98 Volts, 555.90 g/s |
Low Reference | -- | 4.98 Volts, 555.90 g/s | -- |
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 sensor produces an output voltage based on the inlet air flow through the air induction system. This output voltage will display on the scan tool as a voltage parameter and as a grams per second (g/s) parameter. If the ECM detects that the actual MAF sensor voltage signal is greater than or less than the possible range of a normally operating sensor it will set a DTC.
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 0.20 volts or 1.5 g/s for greater than 6 seconds.
P0103
The ECM detects that the MAF sensor is greater than 4.8 volts or 555 g/s for greater than 6 seconds.
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
| • | 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 29-39 g/s at idle to greater than 380 g/s at the time of the 1-2 shift. |
| • | Verify that any electrical aftermarket devices are properly connected and grounded. Refer to Checking Aftermarket Accessories . |
Reference Information
Schematic Reference
Connector End View Reference
Electrical Information Reference
Scan Tool Reference
DTC Type Reference
Circuit/System Verification
- Verify the integrity of the entire air induction system by inspecting for the following conditions:
- In cold climates, inspect for any snow or ice build-up.
- Engine running, observe the DTC information with a scan tool. DTCs P0102 or P0103 should not set.
- 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.
| • | Damaged components |
| • | Loose or improper installation |
| • | Restrictions or leaks in the air induction system |
| • | Water intrusion |
Circuit/System Testing
Perform the Circuit/System Verification before proceeding with Circuit/System Testing.
- Ignition OFF, disconnect the harness connector at the MAF/IAT sensor.
- Ignition OFF and scan tool disconnected for 90 seconds, test for less than 5 ohms between the low reference circuit terminal 4 and ground.
- Ignition ON, verify that a test lamp illuminates between the ignition circuit terminal 3 and ground.
- Verify the scan tool MAF parameter is less than 1 g/s.
- Install a 3A fused jumper wire between the signal circuit terminal 5 and the ignition circuit terminal 3. Verify the scan tool MAF parameter is greater than 500 g/s.
- Remove the air inlet tube to intake manifold. Refer to Exhaust Gas Recirculation Valve Cooler Replacement . Perform steps 1-15.
- Visually inspect the EGR valve and verify the valve is in the closed position.
| ⇒ | If greater than 5 ohms, test the low reference circuit for an open/high resistance. If the circuit tests normal, replace the ECM. |
| ⇒ | If the test lamp does not illuminate, test the ignition circuit for a short to ground or an open/high resistance. |
| ⇒ | If greater than 1 g/s, test the signal circuit terminal 5 for a short to voltage. If the circuit tests normal, replace the ECM. |
| ⇒ | If less than 500 g/s, test the signal circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the ECM. |
Important: Do NOT drain the coolant at this time.
| ⇒ | 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. |
Repair Instructions
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
| • | Mass Airflow Sensor/Intake Air Temperature Sensor Replacement for MAF/IAT sensor replacement |
| • | Control Module References for ECM replacement, setup, and programming |
