9-5 Aero (9600) L4-2.3L Turbo (2.3HOT) (2004)
/l4-2.3l_turbo_(2.3hot)/Page-1579002.png)
Air mass control requests a certain air mass/combustion. Throttle control converts this value to a requested value for throttle position sensor 1 and
compares it with the current value for the sensor.
The difference gives rise to a throttle motor PWM with a polarity that rotates the throttle until the current value corresponds with the requested.
If a major fault should occur in the throttle control, the control module will ground pin 36 and the limp-home solenoid will operate. The solenoid, which
is located on the throttle body, then connects the pedal cable to the throttle spindle. The throttle motor is de-energized and the throttle is then controlled
directly from the accelerator pedal.
The limp-home solenoid is active for 1 s at first and then for 4 x 0.5 s.
IMPORTANT: The solenoid must be energized for short periods only, as it is very low-ohmic.
When the total air mass/combustion requested by the system has been calculated, it must be realized first by the throttle and then, if necessary, by the
turbo control.
The requested air mass/combustion is corrected with the air density in front of the throttle. Thinner air requires a greater throttle angle to obtain the same
air mass/combustion. The density is calculated using the charge air pressure and the temperature of the intake air.
The value is then converted to requested voltage for throttle position sensor 1. The throttle motor rotates the throttle so that the current sensor voltage
corresponds with the requested.
The control module then checks whether the current air mass/combustion corresponds with the requested. If necessary, the throttle position is finely
adjusted.
If the requested air mass/combustion is too high to be handled by the throttle control alone, the excess will be taken over by the turbo control.
If a safety-related fault should occur in the throttle control, it will go into limp-home mode. The CHECK-ENGINE lamp will go on immediately and the
diagnostic trouble code will have to be cleared with the diagnostic tool.
