Accelerator Pedal Sensor (PWG)
The driver's application of the accelerator pedal is monitored by a PWG sensor in the driver's footwell as with previous non-bowden cable EML systems.
The PWG provides two separate variable voltage signals to the ME 7.2 control module for determining the request for operating the Electric Throttle Valve (EDK) as well as providing a kickdown request with automatic transmission vehicles.
The ME 7.2 monitors the changing signal ranges of both circuits as the pedal is pressed from LL to VL.
PWG Pot 1 = 0.5V to 4.5 V
PWG Pot 2 = 0.5V to 2.0 V
Standard transmission vehicles (E39 540i) have slightly lower voltage signals at max throttle position due to the throttle pedal stop (ie Pot 1 = 3.8volts).
However, ME 7.2 programming recognizes the lower values of a standard transmission vehicle as the max throttle position.
In vehicles equipped with an automatic transmission (A5S 440Z), the ME 7.2 recognizes the max pedal value (4.5V) as a kickdown request and signals the AGS via CAN bus.
The signals are continually monitored for plausibility. If the signal ranges are detected as incorrect, ME 7.2 will only utilize the signal of lesser voltage value as a failsafe measure. With this condition, the EDK will also be set to idle (LL) whenever the brake pedal is pressed. Refer to PWG MONITORING AND FAILSAFE OPERATION .