RPG_99

Can anyone point me to the location of the tranny temp sensor[fluid temperature] used by the TCU to keep the TC open? (1999 A8Q)

Is there a specific wire going to the TCU? Any way to check it (resistance check?) without going underneath the car?

CalG

Pin 13 of the transmission harness connector (under the car) is the TOT sensor.

Pins 21 -22 of the TCM connector are the supply and return. (Variable resistance sensor)

Here is the bently procedure

Switch to resistance measuring range

Test step
V.A.G 1598/20
Test of
* Test conditions
Additional steps
Specification
Fault rectification if readout does not match specification

21
21 + 22
Transmission Fluid Temperature Sensor -G93-
* Ignition switched off

Test wiring between control unit and 16-pin connector => Page AUDI-D3-AT03-01-015-0301-184




* ATF temperature







approx. 20 ° C
approx. 0.83 k ? 4)






approx. 60 ° C
approx. 1.28 k ? 4)






approx. 120 ° C
approx. 1.88 k ? 4)



21 + 34

22 + 34

* Ignition switched off
infinite ?
Check wiring harness in transmission; replace if necessary


21 + 54

22 + 54


infinite ?
=> Repair Manual, 5 Spd. Automatic Transmission 01L All Wheel Drive; Repair group 38

Unless a wire is broken (open) these sensors are pretty bullet proof.



CalG

CalG

I was working on the cut and paste and missed the in and out at the transmission connector.

Pins 13 (orange wire) and pins 14 (White wire) are used for the temperature sense. The resistance between these two pins varies with transmission fluid temperature.

That measurement in Ohms is available at the TCM on pins 21 and 22 of the TCM connector. Violet and Black/violet wires.

Good luck!

CalG

CalG

Measuring block 4 Zone 1!
From the book:

>Indicated on display (example)

Display zones:
Display
Display
Designation

1
2
3
4
Group No.
zone


Read measured value block
004
1
ATF temperature


2
Selector lever position - Multi-function Transmission Range (TR) switch -F125--

21.0 ° C
P
1000
0101

3
Multi-function switch position


4
Depending on version: torque reduction or information of On-Board-Diagnosis

RPG_99

Thanks CalG! Exactly what I need

vtraudt

Can someone post the diagram or photo where the TCM is located (and the connector with pin 21/22?