The component hot-film air-mass sensor [HFM] permanently measures the air mass that is taken in (unit: kg/h) with the background of providing the engine management system with optimized data and possibilities for, among other things, the following functions:
The internal structure of the HFM sensor enables it to determine an electrical voltage signal that is proportional to the air-mass flow of the fresh air that is taken in. This signal is output as pulse-width modulated and can be read both in the test module and in the control module functions at
<-Engine operating values> <Actual air mass>.
The housing of the mass air flow meter also contains the intake air temperature sensor (TANS sensor), where the internal structure enables it to return an analog signal that is evaluated in the engine management system. The current temperature of the air taken into the engine's intake system (unit: °C) is measured. This signal can also be read in the control module functions at
<-Engine operating values> <Intake air temperature>.
Service instructions and component information:
A Pierburg HFM6 mass air flow meter is fitted in the present engine. The installation location is on the top side of the engine towards the fresh air intake, directly behind the air filter. The following target values apply:
Diagnosis instructions:
After replacement or re-programming of the engine control module, a learning routine must be executed. This routine is implemented by running the service function <-Adaptations/ learning functions> <HFM, throttle valve, cooler bypass>.