Audi Workshop Service and Repair Manuals

Checking angle senders for throttle valve drive Special tools and workshop equipment required t  -V.A.G 1526 A- t  -V.A.G 1594 A- t  -V.A.G 1598/31-

t  Vehicle diagnosis and service information system -VAS 5052- Test sequence –  Connect up the vehicle diagnostic and service information system -VAS 5052- and select the engine electronics control unit. When doing this, the ignition must be switched on. –  Select the function “Read measured value block”. –  Select “Display group number 062”. –  Check the specifications for the electronic throttle potentiometer voltages in display zones 1 and 2.

	Display zones
	1	2	3	4
Display group 062: Electronic throttle potentiometer voltages
Display	xx %	xx %	xx %	xx %
Display	Throttle valve angle (angle sender 1)	Throttle valve angle (angle sender 2)	Accelerator pedal position sender 1	Accelerator pedal position sender 2
Specification	3...93 %	97...3 %	12...97 %	4...49 %

Note The engine control unit converts the voltage values of the angle senders into a percentage referenced to 5 V and displays these percentage values (5 V supply voltage corresponds to 100 %). –  Observe display zones 1 and 2. –  Slowly floor the accelerator pedal. The percentage display in zone 1 must increase steadily. The tolerance range 3...93 % is not fully utilised in the process. The percentage display in zone 2 must decrease steadily. The tolerance range 97...3 % is not fully utilised in the process.   Note t  The reason for the display in zone 1 increasing whereas the display in zone 2 decreases is the opposing action of the potentiometers (angle senders) in the throttle valve module. t  This means that the voltage tapped at one of the angle senders approaches 5 V (the further the throttle valve is opened, the higher the voltage becomes and the percentage indicated increases). t  The trend of the voltage tapped at angle sender 2 is away from 5 V and towards 0 V (the further the throttle valve is opened, the lower the voltage becomes and the percentage indicated decreases). If the displays are not as described: –  Check voltage supply and wiring to throttle valve module. Pay particular attention to the possibility of loose or corroded connectors. –  Check the accelerator pedal position senders → Chapter. Checking voltage supply of throttle valve module -J338- –  Unplug the connector from the throttle valve module -J338-. –  Switch on ignition.

–  Connect up the multimeter (voltage measuring range) as follows:

Connector Contact	Specification
2 + earth	approx. 5 V
2 + 6	approx. 5 V

If the readings do not match the specifications: –  Check wiring between engine control unit and throttle valve module -J338-. Checking wiring

–  Unplug the connector from the throttle valve module -J338-. –  Connect the test box -V.A.G 1598/31- to the wiring harness to the engine control unit, but do not connect the actual engine control unit → Chapter. –  Check for open circuit and short to earth or positive in the following wiring:

Connector Contact	Test box -V.A.G 1598/31- Socket
1	92
2	83
3	117
4	84
5	118
6	91

–  Eliminate open circuit in wiring/short circuit if necessary. If no fault is found in the wiring: –  Replace the throttle valve module -J338-.