ELECTRONIC THROTTLE SYSTEM – EML
The M54 engines with MS 43/MS 45 engine controls use an electronic throttle control system adopted from the ME 7.2 system on the M62 engine. The system incorporates an electric throttle valve (EDK) and pedal position sensor (PWG) for engine power control.

The MS 43/MS 45 control module monitors the PWG input and activates the EDK motor based on the programmed maps for throttle control. The MS 43/MS 45 module self checks the activation of the EDK via feedback potentiometers motor on the EDK motor.

ACCELERATOR PEDAL SENSOR
The accelerator pedal sensor is similar to the PWG used on the ME 7.2 system. It is integrated into the accelerator pedal housing. Two hall sensors are used to provide the driver’s input request for power.

The hall sensors receive power (5 volts) and ground from the DME control module and produce linear voltage signals as the pedal is pressed from LL to VL.

PWG SENSOR 1 = 0.5 to 4.5 V
PWG SENSOR 2 = 0.5 to 2.0 V

The DME control module uses the signal from sensor 1 as the driver’s request and the signal from sensor 2 as plausibility checking.

ACCELERATOR PEDAL SENSOR

PWG SIGNAL MONITORING & PWG FAILSAFE OPERATION:
• As a redundant safety feature the PWG provides two separate signals from two integral angle hall sensors (HS #1 and HS #2) representing the driver’s request for throttle activation.

• If the monitored PWG signals are not plausible, the DME will only use the lower of the two signals as the driver’s pedal request input providing failsafe operation. Throttle response will be slower and maximum throttle position will be reduced.

• When in PWG failsafe operation, the DME sets the EDK throttle plate and injection time to idle (LL) whenever the brake pedal is depressed.

• When the system is in PWG failsafe operation, the instrument cluster matrix display will post “Engine Emergency Program” and PWG specific fault(s) will be stored in memory.

EDK THROTTLE POSITION FEEDBACK SIGNALS

The EDK throttle plate is monitored by two integrated potentiometers. The potentiometers provide linear voltage feedback signals to the control module as the throttle plate is opened and closed.

Feedback signal 1 provides a signal from 0.5 V (LL) to 4.5 V (VL)
Feedback signal 2 provides a signal from 4.5 V (LL) to 0.5 V (VL)

Potentiometer signal 1 is the primary feedback signal of throttle plate position and signal 2 is the plausibility cross check through the complete throttle plate movement.

EDK THROTTLE POSITION FEEDBACK SIGNALS

EDK FEEDBACK SIGNAL MONITORING & EDK FAILSAFE OPERATION:
• The EDK provides two separate signals from two integral potentiometers (Pot 1 and Pot 2) representing the exact position of the throttle plate.

• EDK Pot 1 provides the primary throttle plate position feedback. As a redundant safety feature, Pot 2 is continuously cross checked with Pot 1 for signal plausibility.

• If plausibility errors are detected between Pot 1 and Pot 2, DME will calculate the inducted engine air mass (from MAF signal) and only utilize the potentiometer signal that closely matches the detected intake air mass.

– The DME uses the air mass signaling as a “virtual potentiometer” (pot 3) for a comparative source to provide failsafe operation.
– If the DME cannot calculate a plausible conclusion from the monitored pots (1 or 2 and virtual 3) the EDK motor is switched off and fuel injection cut out is activated (no failsafe operation possible).

• The EDK is continuously monitored during all phases of engine operation. It is also briefly activated when KL 15 is initially switched on as a “pre-flight check” to verify it’s mechanical integrity (no binding, appropriate return spring tension, etc). This is accomplished by monitoring both the motor control amperage and the reaction speed of the EDK feedback potentiometers. If faults are detected the EDK motor is switched off and fuel injection cut off is activated (no failsafe operation possible). The engine does however continue to run extremely rough at idle speed.

• When a replacement EDK is installed, the DME adapts to the new component (required amperage draw for motor control, feedback pot tolerance differences, etc). This occurs immediately after the next cycle of KL 15 for approximately 30 seconds. During this period of adaptation, the maximum opening of the throttle plate is 25%.

For more Information on the Drive-By-Wire throttle system look at Pico Technology Library page here:

http://www.picoauto.com/applications/electronic-throttle-control.html

MS43 EDK pin Outs

MS45 EDK pin Outs

MS43 PWG pin outs

MS45 PWG pin outs