01M Troubles

[TheTDIWagonGuy]

Hi,
I recently bought a 2000 TDI for my daughter. The transmission is in limp mode. Reverse and 1st work if you select them. D is 3rd gear only. When I scanned the transmission it came up with these codes:


--------------------------------------------------------------------------------
Address 02: Auto Trans Labels: 01M-927-733.lbl
Control Module Part Number: 01M 927 733 HK
Component and/or Version: AG4 Getriebe 01M 4606
Software Coding: 00000
Work Shop Code: WSC 00000
VCID: 0005A2EB001DFB3E71-095C
8 Faults Found:
00258 - Solenoid Valve 1 (N88)
36-00 - Open Circuit
00260 - Solenoid Valve 2 (N89)
36-00 - Open Circuit
00262 - Solenoid Valve 3 (N90)
36-00 - Open Circuit
00264 - Solenoid Valve 4 (N91)
36-00 - Open Circuit
00266 - Solenoid Valve 5 (N92)
36-00 - Open Circuit
00270 - Solenoid Valve 7 (N94)
36-00 - Open Circuit
00268 - Solenoid Valve 6 (N93)
36-00 - Open Circuit
01192 - Torque Converter Lock-Up Clutch
04-10 - Mechanical Malfunction - Intermittent


When I clear them I get:

Fault Codes have been Erased
1 Fault Found:
00811 - System Not Ready for Interrogation (Ross-Tech; Check Fault Codes Later)
35-00 - -


But if I close it and scan again I get the codes back for 1,2,3,4,5,7 when the car is not running. When it is running I get all including 6. I asked CoolAirVw for help and he directed me to his very extensive posts regarding the 01M. It's an amazing resource! So after reading trough it I did some testing and this is what I found:




I've checked the transmission harness and it seems ok. Also I took all measurements from the TCU connector so the entire harness to the transmission.





Any input would be appreciated.

 

[flee]

Just as a starting point I would drop the pan for a filter check and take a close look at the ribbon cable on the valve body.
It is known to be fragile and easily damaged. Any history on rebuilds, etc?

 

[TheTDIWagonGuy]

I did drop the pan to do a fluid and filter. I didn't look very close but the cable looked ok. What I don't understand is why the TCU says that they all have an open circuits but the tests say otherwise.

 

[TheTDIWagonGuy]

Has anybody seen anything like this?

 

[turbovan+tdi]

I did drop the pan to do a fluid and filter. I didn't look very close but the cable looked ok. What I don't understand is why the TCU says that they all have an open circuits but the tests say otherwise.

Heat, temp etc can wreak havoc with the ribbon cable, test the solenoids individually with the cable unhooked.

 

[TheTDIWagonGuy]

OK. So Alchemist was kind enough to sell me a TCU for a reasonable price. I switched it out and the codes are gone! I haven't driven it yet but I'm concerned about what may have caused this on the TCU circuit board.

 

[Geordi]

Looks like a resistor or a capacitor blew. The black squares could be either one, but I'm leaning toward capacitors based on the size of the terminals on them. There are several in that area that don't look good, they obviously overheated. I doubt it was anything your car caused, likely just a freak age failure.

 

[Alchemist]

Those are capacitors, and I will guess they are tantalum.

Failure could be caused by overvoltage, reverse polarity, or they are just old and tired. I have only ever witnessed one tantalum capacitor failure, and it was dramatic, glowing bright red for almost 15 seconds before burning out

 

[Geordi]

I also see two resistors in between the caps that are gone or severely overheated. It looks like definitely one cap blew (lower right) but the one above it doesn't look great either, and then the one to the left is severely blistered from overheating.

It is impressive that the transmission was functioning at all.

 

[turbovan+tdi]

Maybe someone at some point did the old cable switcheroo when jump starting it!