• | 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 | Short to Ground | Open | Short to Voltage |
---|---|---|---|
Operating Conditions: Engine running at various operation conditions Parameter Normal Range: 2,000-10,000 Hz | |||
Ignition 1 Voltage | 0 Hz | 0 Hz | -- |
MAF Sensor Signal | 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 circuit |
• | Ground circuit |
• | MAF sensor signal circuit |
• | IAT sensor signal circuit |
• | IAT 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 on the inlet air flow through the sensor bore. The frequency varies in a range of near 2,000 Hertz at idle to near 10,000 Hertz at maximum engine load.
• | The engine is running for greater than one second. |
• | The ignition 1 signal is greater than 8 volts. |
• | The above conditions are met for greater than 0.5 second. |
• | The DTC runs continuously when the above conditions are met. |
The ECM detects that the MAF Sensor parameter is less than 1,200 Hz for greater than 10 seconds.
The ECM detects that the MAF Sensor parameter is greater than 11,500 Hz for greater than 10 seconds.
DTCs P0102 and P0103 are Type B DTCs.
DTCs P0102 and P0103 are Type B DTCs.
• | A steady or intermittent high resistance of 15 ohms 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 cause the MAF sensor signal to be skewed or erratic. Additionally it may cause a rapid fluctuation in the IAT Sensor parameter. |
• | Circuit Testing |
• | Wiring Repairs |
Powertrain Diagnostic Trouble Code (DTC) Type Definitions
Control Module References for scan tool information
J 38522 Variable Signal Generator
• | Engine running, observe the scan tool MAF Sensor parameter. The reading should be between 1,700-3,800 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 180 g/s at the time of the 1-2 shift. |
• | 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. |
• | 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 ECM. |
⇒ | If greater than the specified range, test the signal circuit for a short to voltage. If the circuit tests normal, replace the ECM. |
⇒ | If the MAF Sensor parameter is not within the specified range, replace the ECM. |
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
• | Control Module References for ECM replacement, setup, and programming |