Audi Workshop Service and Repair Manuals > A3 Mk1 > Power unit | Simos injection and ignition system (4-cylinder) | Mixture preparation system, electronic inj.,Gas | Checking electronic engine power control (electronic throttle) | Checking angle sender for throttle valve actuator

Test sequence

–	Connect vehicle diagnostic, testing and information system -VAS 5051- or fault reader -V.A.G 1551- and select engine electronics control unit by entering “address word ” 01. For this purpose, the ignition must be switched on.

Indicated on display:

–	Enter “08” for the function “Read measured value block” and confirm entry with the Q key.

Rapid data transfer            HELP

Select function XX

Indicated on display:

–	Enter “062” for “Display group number 062” and confirm entry with the Q key.

–	Check specifications for electronic throttle potentiometer voltages.

Reading measured value block                  Q

Enter display group number XXX

	Display zones
	1	2	3	4
Display Group 062: Electronic throttle potentiometer voltages
Display	xx %	xx %	xx %	xx %
Readout	Throttle valve angle (angle sender 1)	Throttle valve angle (angle sender 2)	Accelerator position sender	Accelerator position sender 2
Range	0...100 %	100...0 %	0...100 %	0...100 %
Specification	5.9...92.2 % (Idling speed value: 5.9...15.2%; Full load value: 84.0...92.2 %)	95.1...8.7 % (Idling speed value: 84.2...95.1 %; Full load value: 8.7...15.4 %)	12...97 %	4...49 %

Note!

The engine control unit converts and displays the voltage readings from the angle senders as percentages of 5 V. (5 Volt supply corresponds to 100%).

–	Observe readouts in display zones 1 and 2.

–	Slowly depress accelerator pedal.

Percentage displayed in zone 1 should rise evenly. The tolerance range of 5.9...92.2 % is not fully utilised.

Percentage displayed in zone 2 should fall evenly. The tolerance range of 95.1...8.7 % is not fully utilised.

Note!

t	The reason why the value in display zone 1 rises and that in zone 2 falls is that the potentiometers (angle senders) in the throttle valve control unit operate in opposite directions.

t	This means that the voltage picked off by one of the angle senders runs towards 5 V. (As the throttle is opened, the voltage becomes greater and the percentage increases).

t	The voltage picked off by the angle sender 2 runs from 5 V towards 0 V. (As the throttle is opened, the voltage becomes smaller and the percentage decreases).

If the displays are not as described:

–	Check the voltage supply and wiring to throttle valve control unit → Chapter. Pay particular attention to connectors, which may be loose, not properly engaged or corroded.

–	Check the accelerator position senders → Chapter.

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