Electronic Throttle Module (ETM)

The electronic throttle module contains a microprocessor has the task of controlling the throttle in response to requests from the engine control module (ECM) but also to diagnose and supervise its own function and if necessary requests the Electronic throttle system warning lamp to be lit, via engine control module (ECM) to the Can driver information module.

The electronic throttle module controls and constantly compares the analog accelerator pedal module signal, sent from the engine control module (ECM) onto the network, with the digital Pulse width modulated signal to determine if the signal from the engine control module (ECM) is within limits.

The engine control module (ECM) can request that the Electronic throttle system warning lamp is lit but the request is transmitted directly to the Can driver module.

The electronic throttle module contains a continuous torque motor which is ungeared and operates directly onto the throttle spindle.

The torque motor is supplied with 12 V and is controlled by the electronic throttle module using signals from the accelerator pedal (AP) position sensor, accelerator pedal module (APM), over requested throttle opening and from both potentiometers about current throttle position.

Both potentiometers are supplied with 5 V and are installed in each end of the throttle spindle.

For safety reasons it has been decided to use 2 potentiometers which each send the same throttle position signal to the electronic throttle module (ETM). With the throttle closed the signal is 0.5 V and at wide open throttle (WOT) approximately 4.5 V.

If one of the potentiometer signals is missing the electronic throttle module can still determine throttle position using the second signal and the car can still drive normally.

The throttle body (TB) mating surfaces are spherical and provides better resolution per degree of opening. This gives more accurate flow control from idling position up to approximately 20% open throttle. The effect is a smoother start at throttle opening/acceleration.

All signal exchange between the engine control module (ECM) and the electronic throttle module is via the network.