sloss Posted December 1, 2008 Report Share Posted December 1, 2008 My D2 '02 4.2 A8 Auto decided to go into 'Limp Home Mode' on Saturday morning - a very cold one it was too minus 5. Started it up and noticed all the PRNDS lights on in Auto and no tip working... Got the book and went indoors for a cuppa while I found out what to do. Came back out to find it it was fine. On Sunday evening I was again going out - very cold again - and same problem so I took another car instead. Monday morning, temp outside now plus 3 and it was fine - all systems normal. I'm thinking a switch/sensor that doesn't like the cold, maybe some water in it that freezes? Any ideas gentlemen? Should I read the Codes? Stew, Link to comment Share on other sites More sharing options...
IT_S8 Posted December 1, 2008 Report Share Posted December 1, 2008 My D2 '02 4.2 A8 Auto decided to go into 'Limp Home Mode' on Saturday morning - a very cold one it was too minus 5. Started it up and noticed all the PRNDS lights on in Auto and no tip working... Got the book and went indoors for a cuppa while I found out what to do. Came back out to find it it was fine. On Sunday evening I was again going out - very cold again - and same problem so I took another car instead. Monday morning, temp outside now plus 3 and it was fine - all systems normal. I'm thinking a switch/sensor that doesn't like the cold, maybe some water in it that freezes? Any ideas gentlemen? Should I read the Codes? Stew, Limp home mode is a feature of the Gearbox ECU getting confused by what the gearbox sensors are telling it, giving up and dropping the box into 3rd gear in hopes it gets you home.... The interesting thing is that it should only really happen when you're moving, as it would normally take a mechanical failure of sorts, eg ECU wants 2nd gear but gearbox clutch fails to select it, so input/ouput ratios fall outside of plausible values and ECU detects failure..... If you get limp mode before you even get moving, that does suggest something more electrical in my eyes. Having recently dismantled an Audi box I'm pretty convinced that nothing outside exposed to the elements moves, and everything inside is coated in oil. Freezing up a component in that way doesn't sound likely. We had -5 here in Harrogate and 2 D2's here started no probs.... Did you get as far as trying to select a gear before it failed, or was it literally ignition on and all lights lit? Sorry, forgot to say - Get the codes, They will point you in the right direction no doubt Link to comment Share on other sites More sharing options...
sloss Posted December 1, 2008 Author Report Share Posted December 1, 2008 Thanks for that info. Saturday morning I reversed out my yard and on selecting forwards it seemed to be sluggish. By the time I reached the top of my track I noted that all the Gear Lights were on so turned it round and went back and as I said, switched it off, had a coffee, came back out and it was fine. Only thing I can think of was I shifted it into D while still going backwards and it gave a bit of a clunk - normally no noise. I'm talking almost stopped before selecting forwards as I know the problems. On the Sunday evening the Gear Lights were on right away - no movement at all - I was watching the display hoping it would be OK. This morning A-OK. The only similar conditions I can think of was the very cold weather. Link to comment Share on other sites More sharing options...
sloss Posted December 1, 2008 Author Report Share Posted December 1, 2008 When I started it at 4ish this evening to come home it showed all the Auto Lights on right from key on. I got it to the first set of traffic lights, about 2-300 yards and was stopped so I turned it off then on again - normal service! I've just downloaded the codes this evening. Here's the code I found: Monday, 01 December 2008, 19:32:29 VAG-COM Version: Release 409.1-S Control Module Part Number: 4D0 927 156 EA Component and/or Version: AG5 01L 4.2l5V RdW 1010 Software Coding: 00001 Work Shop Code: WSC 02314 1 Fault Found: 18227 - Pressure Control Valve 2 (N216): Open or Short to Ground P1819 - 35-10 - - - Intermittent --------------------------------------------------------------------------- What's the script now...? Stew, Link to comment Share on other sites More sharing options...
Malairt Posted December 2, 2008 Report Share Posted December 2, 2008 My 143k D2 goes into limp mode whenever I stop on a hill facing upwards. Switch off and restart the engine and it's fine - till next time. I assume it's a switch of some kind playing up but I'm too skint to fix it. Best of luck in finding your solution Link to comment Share on other sites More sharing options...
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