ricointheuk Posted June 25, 2008 Author Report Share Posted June 25, 2008 Just remembered something about the car before the problems. The MPG went do to 16mpg even on the motorway where I normally get 27mpg. Hope that gives someone an idea of what the misfire and CAT light flashing could be. So far: 1. Changed the Lambda probes x 2 2. new plugs 3. new coil pack 4. checked all pipes. Found a crack in the intake boot that connects to the engine and replaced this. Link to comment Share on other sites More sharing options...
LostKiwi Posted June 25, 2008 Report Share Posted June 25, 2008 Check the exhaust just near the Cats. If there is a second Lambda probe then yes you do have pre and post sensors (not all A8s do). Its always possible the Cat is the real problem of course and that the light is correct! Link to comment Share on other sites More sharing options...
harpersimon Posted June 25, 2008 Report Share Posted June 25, 2008 Check the exhaust just near the Cats. If there is a second Lambda probe then yes you do have pre and post sensors (not all A8s do). Its always possible the Cat is the real problem of course and that the light is correct! :roflmao:a warning light that is actually wanring you of something.. never!! he's got a point though.. Link to comment Share on other sites More sharing options...
wsurfa Posted June 25, 2008 Report Share Posted June 25, 2008 The breather pipes are all ok. They need changing but are still sealed. Is there a way to test the ignition module. What cost is it?Thanks it was c£90 - no idea how to test it - just the decription I got from the guy who serviced mine Link to comment Share on other sites More sharing options...
a13bee Posted July 28, 2008 Report Share Posted July 28, 2008 hi if you hav,nt sorted it yet i had the same problem and it turned out to be the amplifiers located drivers wing under bonnet under a plastic black cover just after the filter box near the wash wipe filler hope this helps i had loads of people saying its the coil packs its the ecu its the plugs and in the end it was just the amplifiers 2 amps 1 for each bank of 4 hope this helps good look bro Link to comment Share on other sites More sharing options...
ricointheuk Posted July 28, 2008 Author Report Share Posted July 28, 2008 hi if you hav,nt sorted it yet i had the same problem and it turned out to be the amplifiers located drivers wing under bonnet under a plastic black cover just after the filter box near the wash wipe filler hope this helps i had loads of people saying its the coil packs its the ecu its the plugs and in the end it was just the amplifiers 2 amps 1 for each bank of 4 hope this helps good look bro Hi a13bee Thank you for your suggestion, as I have not fixed the problem yet. I will try this first. Also on my list to try is ECU and changing the CAT's, MAF sensor,post CAT sensors, injector cleaner. I do keep check back here for updates from helpful people and will post on any success / failure I have from things I try. Thanks Richard Link to comment Share on other sites More sharing options...
ricointheuk Posted July 29, 2008 Author Report Share Posted July 29, 2008 hi if you hav,nt sorted it yet i had the same problem and it turned out to be the amplifiers located drivers wing under bonnet under a plastic black cover just after the filter box near the wash wipe filler hope this helps i had loads of people saying its the coil packs its the ecu its the plugs and in the end it was just the amplifiers 2 amps 1 for each bank of 4 hope this helps good look bro My misfire and CAT light were caused by leaking breather pipes and a faulty ignition module.Now running just fine. I think you two are correct. I checked the modules via the very clear process on this web page: AudiWorld Forums: DIY test of power output stage/ignition amp module N122 (long & BWW) One of my outputs is dead. (subject to me doing it correctly!) I will purchase another module and see if that solves the problem and update you. Thanks Richard Link to comment Share on other sites More sharing options...
ricointheuk Posted July 30, 2008 Author Report Share Posted July 30, 2008 Its FIXED!!! I put the new ignition amplifier on today and she's back to normal When I started the car the misfire was gone and the CAT light went off after about 10 secs. Thanks to all that have posted and helped me solve the problem. Thanks Richard Link to comment Share on other sites More sharing options...
a13bee Posted August 5, 2008 Report Share Posted August 5, 2008 well done bro like i said i had the same problem with my a8 it took a while but i got it sorted but please dont forget to have the codes cleared because the memory remembers and it could flash up again so make sure you get it cleared regards a13bee.well done bro Link to comment Share on other sites More sharing options...
ricointheuk Posted February 29, 2012 Author Report Share Posted February 29, 2012 Hi All Update 29 Feb 2012( 3-4 years later)... Happened again at the start of a 2hr journey back home yesterday. At least I had a good idea what the misfire/CAT light flashing was this time Made it home. Tested the modules again and found a fault again on one cylinder. While searching for prices for the new part I came across a site that had opened one up and found a lose wire, they then re soldered the joint and it worked again. I followed the walk-through and re soldered my part and it worked too!(So far etc!) Here is the link: Repairing BOSCH 4D0 905 351 ICM Unit - uk-mkivs r Link to comment Share on other sites More sharing options...
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