AudHaus

Many thanks to PaulW and ttuling who helped me diagnose my problem and prove that my problem was electrical inside the transmission. It isn't easy finding a shop that will go inside the automatic transmission, but I found Auto Europa off Rt 9 in Newton, MA, and thought Aaron, who worked on my car, really knew what he was doing. We had to wait almost a week for the wiring harness inside the tranmission to be shipped from Germany. He also replaced a relay in the area by the TCU, which he suspected might be bad and could have caused the wiring failure. The wiring harness is full of diodes which were out of spec, plus the smoked one.

It's all put back together with a new transmission fluid filter, and I'm happy to have a fully working car again for the first time in a long time. Now I have to remember that it is a wonderful car rather than a POS. Here's hoping it stays that way!

seanA8

Mine was the same issue. I had a guy try to replace the Bosch box in the dash that listed for $1500. It turned out to be the wiring harnass as well. I hate to think how I could have spent $3-5k without people on this board. Thank God for the Internet!

JimR

How much was that little piece of harness?

Dan McBoost

What was the car doing before? I missed your post. I'd search but it never works right for me.

AudHaus

I wrote too soon. Limped home tonight. Same code 18243.

AudHaus

https://forums.audiworld.com/a8/msgs/94681.phtml
https://forums.audiworld.com/a8/msgs/94903.phtml
https://forums.audiworld.com/a8/msgs/95143.phtml

tozoM8

sensor and a diode for the transmission temperature. I've disconnected the temperature sensor before, it didn't give me any codes.

AudHaus

Water ingress in TCU/ECU area. Not flooded, only a mm of water in places on bottom, but several harnesses soaked, and connectors on back (where it appears to have been coming in) all wet. Mechanic left off a couple of screws on the cover, grrr! I found them still on the air inlet above the TCU cover. (I thought WTF did I put those there for, and then discovered none were missing any more.)

I'm wondering if the codes were cleared, because measurements make no sense compared to spec or what they were before and don't indicate that code should necessarily have been thrown.

Pins 52,53, should be < 1 Ohm is infinite (indicating double power wiring isn't connected any more)
51 - 34 infinite as it should be.
All pressure control valve readings should be 6-10 Ohms but instead are:
1: very low (fluctuates between 0.3 and 1)
2: infinite
3: infinite
4: very low (also fluctuates)
5: infinite

ttuling

The two common solenoid power supply wires are no longer connected to each other on mine too. One feeds some of the solenoids & control valves, the other feeds others. I'll bet your other wire shows readings where you currently see "infinite".

Have you checked your meter's readings against a known resistance or another meter? I'm hoping you have an inaccurate meter and a bad pressure control valve 5.

You probably caught the water ingress in time. Ask the careless mechanic to pay for some Stabilant contact enhancer which you can put on whatever got wet. (Except O2 sensor wires -- capillary action draws the stuff into the sensors and ruins them.)

(And why do I have a new ZF-rebuilt transmission in my car? Because reverse failed at 90,030 miles. Clutch F seal debonded. Not an entirely unknown problem.)

Tom