forum.audiv8.com Foren English Audi V8 Forum Auto gear box Limp-home mode?!?!?

Hi there I have a v8 auto 3.6 and the auto gear box every so often goes into something like limp home mode, just stats in one gear. I have noticed that it's happen in stop start traffic more than any other time. If you pull over and switch off and startup it's perfectly fine, it's as if it's getting confused. If I switch it to manual that's doesn't work either.

Has anyone else had the same issue? Or has any one got any ideas on what the problem my be?

I have checked other posts and can't seem to find anything about this problem

Thanks nick

How is the cooling?
And also the age of the transmission oil and filter?
Here's a little history of similar events on mine.

First.
Very old fluid was making the box rather clunky. At the time, I didn't have access to a filter, so I only drained the box, and refilled with new fluid. It made a world of difference.

Overheating cooling system.
When I had an issue with overheating, a side effect was that the transmission would frequently lock in one gear, and stay there, until the ignition was turned off.
Initially, it didn't appear that I was having a cooling problem.it became gradually worse. My supposition was that gearbox cooling circuit was suffering simply because the engine cooling was not normal.

This also manifested mostly in stop start/ slow speed traffic.

My cooling problem was actually a failed viscous coupling for the fan. Worth checking. Have a look at one of my threads.

Hi mark.

As far as I'm aware there is no issues with the heating the temperature doesn't seem to increase a Hugh amount in traffic so guess that's ok?

I have only had the v8 for nearly a year. It's go full audi service up to 4 years ago so I guess it might be worth an gear box oil and filter change.

Nick

If you do a fluid change, beware that there is a prescribed amount and method of checking levels. The issue being quantity of fluid. Too much resulting in damage, which it is very easy to overfill unknowingly. Most cars don't have the dip stick in the transmission. Helpful to Audi servicing years back, but not so much help now.
I purchased a dipstick for mine. (Audi parts, wasn't too pricey)

Hey Nick,

are all the "gear lights" on? In this special case you gaerbox is in an electrical emergency mode -> only third gear.

I´d the same fault a couple of month ago. First you should check your throttle-valve sensor aspecially the plug. If this doesn´t work you could check the Hall sensor on right distributer, if there is a short circuit your throttle-valve senser doesn´t work either! (Same circuit!!)

The Dip stick NLA from Audi.
I have modified a dipstick from an Audi 100 C4 auto, from Ebay,they are a bit longer
Still got to get your back to you Mark

I´ve to correct myself... electrical emergency mode is without any lights on. So everything seems to be normal but the gearbox only uses the third.

I´m pretty sure that you´ll have a problem with the throttle sensor (G69)

1. Cleaning contacts (Cantact spray)

if it doesn´t work ..

2. Read ot the fault recorder by using VCDS or the "old-school" -way
possible codes are:
00518 - G69 faulty
00529 - REV information is missing
00538 - reference voltage
00545 - Signaling ECU <-> geabox ECU broken
00549 - consumption signal