Diagnosable Tiptronic control unit

A self-diagnosis feature with fault memory is built into the Tiptronic control unit to allow certain faults within the electronic control system of the Tiptronic to be detected and to be stored.

To prevent detected and stored faults from being erased when the ingition is switched off, a permanent positive voltage is present at the control unit. Detected faults remain stored in the fault memory for at least 50 starts of the engine. Caution:

If the connector is pulled off the Tiptronic control unit or if the battery is disconnected, the fault memory is erased.

Tester connections

To run the diagnosis, the vehicles are fitted with a 19-pin connector in the passenger footwell.

This connector allows System Tester 9288 or the Flashing Code Tester 9268 (via adapter cable 9268/2) to be connected. Operation of the testers is described in the tester instruction manuals.

Note

The relevant test point is complemented by the corresponding fault flasher code of Tester 9268. As of tester module level 4.0, the following items can be checked or read out with System Tester 9288:

Input signals with „Input signals" menu

Kickdown Downshift Upshift

Manual program Selector lever

Actual values with „Actual values" menu

Speed 1

Speed 2

Injection time

Throttle

Temperature

Transverse acceleration

Selector lever switch

Gear

Voltage supply Version coding

Actuators (Drive links) with „Drive links" menu

Solenoid valve 1 Solenoid valve 2 Torque converter clutch Gear indicator 1 - 4 Reverse relay (G 01) Ignition timing change

General Auxiliary tools

Use of the following auxiliary tools is recommended when checking the Electronic Transmission Control (EGS - Elektronische Getriebe Steuerung):

• Diagnosis Tester 9288 with connection cable

• Voltage and resistance meter for internal resistance >10 MQ

• Oscilloscope

• Jump lead with matching spade connectors General information

• Do not run resistance measurements on live wiring

• If poor terminal connections are found,

- check wiring for damage

- check connector terminals for tight fit, tight wire connections, deformation and corrosion

- Before replacing the transmission or the electronic control unit, always check the wiring harness and system components with the System Tester. Otherwise new new control unit or transmission may be destroyed again.

Abbreviations:

TE = Transmission electronics= - System components ECU = Electronic transmission control unit HCU = Hydraulic transmission control unit

Signals that can be checked with the oscilloscope

• Speed signal (from transmission)

Definitions System voltage

The system voltage reflects the current charging state of the battery. When the battery is discharged, the voltage is approx. 11 V; when the engine is running it is approx. 14.5 V

Needle pulse

Needle pulses are pulses of extremely short duration that appear as a vertical line on the oscilloscope (tr signal)

Unit functions

Installed units must operate correctly within a voltage range of 9.5 to 16.8 Volts.

Do It Yourself Car Diagnosis

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