dent

04 a4 avant (B6) quattro - ZF5HPFLA auto trans

I cannot diagnose what's going on, but would like to figure out exactly what's wrong before throwing parts at it. Here's what I am experiencing -

The from a stop, the trans is slipping in D or S and eventually goes into limp mode (PRNDS backlit red). If you turn off the car and turn it back on, it goes back to normal until you try to drive in D or S again. Before going into limp mode, the letter you shift into is backlit like normal. I believe the limp mode just forces the transmission into 3rd or 4th. The code I pull from VCDS is - 17114 - Gear Ratio Monitoring: Incorrect Gear Ratio / P0730 - 003 - Mechanical Failure.

Reverse and tip/tiptronic/manual mode works though. Smooth shift into reverse. No issues there. If you put it into tip, there's a lag and it slams it into gear pretty hard. Will lurch pretty bad. Once that's done though, shifts up and down through all the gears just fine.

Fluid level is fine. I want to believe there is some kind of communication error. Already replaced the neutral safety switch on the side of the trans. I don't believe there is a mechanical failure because I can shift through all the gears fine in tip. Does D or S use a solenoid or do something to the torque converter that driving in tip doesn't? Could there just be a signal lost from the shifter or TCU? Any troubleshooting tips?

turbo510

Since you have VCDS, use that to verify that your shifter position matches what the TCM is reporting. Also, output tests will click the solenoids on and off, audibly in a quiet garage with the engine OFF. I read of one person having a very similar issue as yours; reverse OK but 17114 when trying to go forward. He found water inside the transmission connectors (although I know that you have serviced the 'range switch'). The other connector is the critical one which supplies current to the bank of solenoid valves, plus transmits the temperature and speed signals back to the TCM.