• | 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. |
Circuit | Short to Ground | High Resistance | Open | Short to Voltage | Signal Performance |
---|---|---|---|---|---|
Ignition 1 Voltage | P0102 | P0101 | P0102 | -- | P0101, P0103 |
MAF Sensor Signal | P0102 | P0102 | P0102 | P0102 | P0101, P0103, P1101 |
Ground | -- | P0102 | P0102 | -- | P0102 |
Circuit | Normal Range | Short to Ground | Open | Short to Voltage |
---|---|---|---|---|
Ignition 1 Voltage | -- | 0 Hz | 0 Hz | -- |
MAF Sensor | 1,700-9,500 Hz | 0 Hz | 0 Hz | 0 Hz |
Ground | -- | -- | 0 Hz | -- |
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:
• | 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 9,500 Hertz at maximum engine load.
• | The engine is running for greater than 1 second. |
• | The engine speed is greater than 300 RPM. |
• | The ignition 1 signal is greater than 8V. |
• | The above conditions are met for greater than 1 second. |
• | This DTC runs continuously within the enabling conditions. |
The ECM detects that the MAF Sensor parameter is less than 10 Hz for greater than 5 seconds.
The ECM detects that the MAF Sensor parameter is greater than 11,000 Hz for greater than 5 seconds.
DTCs P0102 and P0103 are Type B DTC.
DTCs P0102 and P0103 are Type B DTC.
• | A steady or intermittent high resistance of 15RΩ 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. |
Powertrain Diagnostic Trouble Code (DTC) Type Definitions
Control Module References for scan tool information
J 38522 Variable Signal Generator
For equivalent regional tools, refer to Special Tools.
• | Engine Running, observe the scan tool MAF Sensor parameter. The reading should be between 1,700-3,200 Hz depending on the engine coolant temperature (ECT). |
• | 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 100 g/s at the time of the 1-2 shift. |
• | 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. |
• | Loose or improper installation |
• | Water intrusion |
⇒ | If greater than the specified range, test the ground circuit for an open/high resistance. |
⇒ | If the test lamp does not illuminate, test the ignition circuit for a short to ground or an open/high resistance. |
⇒ | 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. |
⇒ | If the MAF Sensor parameter is not within the specified range, replace the K20 ECM. |
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
• | Control Module References for ECM replacement, setup, and programming |