Throttle Body: Testing and Inspection
28 Electronic ThrottleElectronic Throttle Control (ETC) Motor Control Circuit
Monitoring Descriptions:
ETC Driver diagnosis (H-bridge): The ETC - H-Bridge IC continually checks the MTC if there is a short circuit to battery voltage or ground.
In addition the IC is able to detect over temperature. This is performed internally to the ECU.
ETC spring check (start routine)
This Diagnosis checks if the throttle spring is working correctly and if the throttle limp home position can be reached.
The diagnosis is performed at the beginning of every driving cycle at ignition "Key ON" position.
ETC adaptation diagnosis
After the initial engine start and / or component change, the characteristic Potentiometer values for the limp home position and the lower mechanical stop are learned within an adaptation routine. The values are stored at the end of the driving cycle in the non-volatile memory.
If the conditions are not fulfilled, the malfunction errors (DTC's) are stored.
Electronic Throttle Control (ETC) Motor Control Performance
The task of this diagnosis is to detect a throttle valve error or a jammed ETC actuator. The diagnosis observes the ETC position controller system deviation TPS_DIF dependent on the gradient of the throttle position setpoint. The anti-bounce of the error detection is done by the generic error management. The increment and decrement value of the anti-bounce algorithm can be calibrated.
Additionally the PWM output of the digital position controller is monitored by this diagnosis function. If the absolute value of PWM_ETC exceeds a defined diagnosis threshold than an reversible error will be indicated and a speed limitation is requested. If the absolute value of PWM_ETC exceeds the threshold after speed limitation for a defined time an irreversible error for the driving cycle is set. The aim of this function is to protect the ETC components, because a high current of the rotor electrical circuit over a long time can destroy the ETC components
Electronic Throttle Control (ETC) Jam Detection
In case of very low temperatures it is possible that the throttle actuator is jammed by ice. The functionality is used for the detection and the removing of ice between throttle flap and body. The functionality is able to detect the location of the throttle flap disturbance and can distinguish ice in closing and opening throttle flap direction.
The ice shall be removed with a variation of the set point for the digital position controller
Flow Chart: Throttle Actuator (ETC) Adaptation Diagnosis
Flow Chart: Throttle Actuator (ETC) Controller Performance Diagnosis
Flow Chart: Throttle Actuator (ETC) Jam Detection
Flow Chart: Throttle Position Sensor - Electrical Check
Flow Chart: Throttle Position Sensor 1 vs. Sensor 2 Rationality Check
