Throttle Position Signals (EML)
THROTTLE POSITION SIGNALS WITH BOSCH EML SYSTEMS (M70 & M30 ENGINE EQUIPPED VEHICLES WITH ASC)
The throttle position inputs (LL & VL) to the engine control module(s) produced by the Bosch EML control module are ground inputs. The EML control module recognizes LL & VL conditions and provides the appropriate ground signal input to the ECM(s).
CLOSED THROTTLE (LL) SAFETY CIRCUIT
As a backup safety signal for the EML produced signal, a hard wired "closed throttle" circuit is installed. This signal is provided by a safety switch in the pedal position sensor (PWG) and is wired through the brake pedal test switch.
With the accelerator pedal in the closed throttle position and the brake pedal depressed, a ground path is established to the engine control module(s) "closed throttle" input, duplicating the EML produced signal.
THROTTLE POSITION SIGNALS WITH SIEMENS EML IIIs SYSTEM
(M73 ENGINE EQUIPPED VEHICLES)
The throttle position in put (LL) to the engine control modules are produced by the EML control module. The EML control module recognizes LL conditions and provides a switched voltage signal to the ECM(s). Part load and VL (full throttle) signals are provided by the EML Ills control module to the engine control modules over the CAN bus.
CLOSED THROTTLE EXTERNAL SAFETY PATH
The external safety path input is connected between the engine control modules and the accelerator pedal (PWG). If the engine control modules receive a high signal on the safety path input, the decel fuel cut off function is activated. This safety feature ensures that the DME control modules will not allow engine RPM to exceed idle if the EML system malfunctions.
The external safety path exists from the brake light switch through the pedal position sensor 40 switch to the DME control modules.
If the accelerator pedal is released, the 4° switch closes. If the engine does not return to idle, stepping on the brake will apply a high signal through the 4° switch to the DME control modules. With this signal, decel fuel cut off is activated.