Test sequence

The charging pressure sensor is checked for indication of plausible values.
The intake air temperature sensor and charge-air temperature sensor are checked for signal plausibility
The hot film air mass meter is tested at cutoff speed and at idle speed by comparison of the measured and theoretically calculated air mass.
At the same time, there is a check as to whether the system builds up the charging pressure quickly enough and to a high enough level.
Functional check of the exhaust-gas recirculation actuator and the charging pressure actuator/turbocharger by means of the following automatic test procedure:
- Activation of the charging pressure actuator at minimum pulse duty factor (TV)
- Gradual opening of the exhaust-gas recirculation actuator, measurement of the air-mass change
- Closure of the exhaust-gas recirculation actuator
- Activation of the charging pressure actuator at maximum duty cycle
- Gradual opening of the exhaust-gas recirculation actuator, measurement of the air-mass change
The idling speed is automatically increased for this test.
The measured changes in air mass flow are automatically analyzed. They are compared with one another in such a way that conclusions can be drawn as to the function of the exhaust-gas recirculation actuator, the charging pressure actuator and the turbocharger.