Mass Air Flow And Temperature Sensor
The Mass Air Flow and Temperature (MAFT) sensors allow the Powertrain Control Module (PCM) to measure the mass air flow and the air temperature. The PCM requires the mass air flow into the engine. The mass air flow is measured with a hot film element in the sensor. The temperature of the air flow is measured with a Negative Temperature Coefficient (NTC) resistor in the sensor. The mass air flow is used to determine the fuel quantity to be injected. The correct air and fuel mixture maintains the stoichiometric air:fuel ratio required for correct operation of the engine and the catalytic converters.
Identical MAFT sensors are attached to each of the air cleaner outlets. On each MAFT sensor, a 5-pin electrical connector provides the interface with the engine wiring harness.
If the hot film element signal fails the PCM invokes a software backup strategy to calculate the mass air flow from other inputs. Closed loop fuel control, closed loop idle speed control and evaporative emissions control are discontinued. The engine will suffer from poor starting, poor throttle response and if the failure occurs while driving, the engine speed may reduce before recovering.
If the NTC resistor signal fails the PCM adopts a default value of 25°C (77°F) for the intake air temperature.