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D2 - Transmission Gearboxes, diffs, drive shafts. |
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Thread Tools | Display Modes |
#1
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Brake switch cause limp mode?
So I picked this A8 up yesterday, it drove back and for some fortunate reason it didn’t hit limp mode for about 90 Miles, kickdown worked if a little lathargic, lock up was fine and didn’t seem to slip at all.
Now the fault codes are the g195 implausible signal 17105 and brake switch electrical malfunction 17087 these codes where cleared and return by the way. The reason I wondered if it’s the brake switch as if I cycle ignition and drive straight off the box stays out of limp mode, but if I hold the brake pedal for any amount of time at standstill the box usually clunks into limp mode, I can brake whilst moving without issue just when it comes to a stop, I’ve tried google and on here but not a lot of info, anyone else came across anything similar? Just the fact the box behaves like normal whilst running is what is throwing me regarding the speed out put signal issue. Just incase, the car is a PFL 4.2 4 speed Thanks guys.
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#2
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That sounds like 2 different problems. The G195 issue would more likely give limp mode.
And on a PF (non-DBW) D2 you get a brake switch fault anyway unless you dab the brakes before doing a scan. So that may be 100% spurious. See: http://wiki.ross-tech.com/wiki/index...7/P0703/001795 Quote:
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2003 D2 FL S8. Irish Green Pearl/Beige. Solar sunroof, auto-dim mirrors, electric rear seat functions and extended leather. Ski hatch retrofit. Aftermarket reversing camera. DVB-T and XCarlink now removed as redundant. 2016 Volvo V40 T5 Cross Country (4WD) with ALL the toys including adaptive cruise etc. etc. Osmium Grey with Blonde/Charcoal leather interior. Polestar performance "optimisation". (Even rarer than a D2 S8!) Oh, and a brand new engine at just under 30,000 miles on the factory one! Finally: gone, but not forgotten..... 1998 D2 PF S8. Agate Grey/Platinum. Every option (I think) except electric rear seats, Tiptronic steering wheel, ski hatch, towbar & dimming door mirrors. e.g. Cruise control, NavPlus/TV, Bose, GSM, Xenons, Solar roof, Parking sensors, Alcantara/leather everywhere of course. (internal dimming mirror added later) 1998 (very early) Ford Focus 1.8 Zetec; ABS/TCS, Heated screen/mirrors, Aircon. Added Auto-dim mirror, Leather seats, Trip computer, Cruise control, OEM Ford SatNav with CD changer. And before that a lot of Rover 800s, a few oddities, a lovely Triumph Dolomite 1850HL with Overdrive and way back in my schooldays an Austin Seven aka Mini 850! Last edited by HPsauce; 10th December 2017 at 11:52 AM. |
#3
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Would it only cause limp mode when stationary? Pretty sure brake fault is present as cruise doesn’t work iirc, but I will double check
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#4
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Turn on ignition and start car, check TCM codes, press brake firmly and check again.
Then go for a short drive and check again with engine still running. That should help clarify things. Cruise not working could be several things including a faulty stalk and faulty control module (it's a separate unit in the ECU box under the bonnet).
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2003 D2 FL S8. Irish Green Pearl/Beige. Solar sunroof, auto-dim mirrors, electric rear seat functions and extended leather. Ski hatch retrofit. Aftermarket reversing camera. DVB-T and XCarlink now removed as redundant. 2016 Volvo V40 T5 Cross Country (4WD) with ALL the toys including adaptive cruise etc. etc. Osmium Grey with Blonde/Charcoal leather interior. Polestar performance "optimisation". (Even rarer than a D2 S8!) Oh, and a brand new engine at just under 30,000 miles on the factory one! Finally: gone, but not forgotten..... 1998 D2 PF S8. Agate Grey/Platinum. Every option (I think) except electric rear seats, Tiptronic steering wheel, ski hatch, towbar & dimming door mirrors. e.g. Cruise control, NavPlus/TV, Bose, GSM, Xenons, Solar roof, Parking sensors, Alcantara/leather everywhere of course. (internal dimming mirror added later) 1998 (very early) Ford Focus 1.8 Zetec; ABS/TCS, Heated screen/mirrors, Aircon. Added Auto-dim mirror, Leather seats, Trip computer, Cruise control, OEM Ford SatNav with CD changer. And before that a lot of Rover 800s, a few oddities, a lovely Triumph Dolomite 1850HL with Overdrive and way back in my schooldays an Austin Seven aka Mini 850! |
#5
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Quote:
One circuit really only triggers the brake lights, the other informs the ECUs and they are ever so slightly set apart so that one changes just before the other as you apply the brakes. You can check the operation with the relevant measuring blocks using VCDS, just can't recall which ones they are. (Used that to diagnose that mine was mis-adjusted and causing odd gearbox behaviour) Edit: Engine measuring block 66, at least on FL. This is what I said nearly a year ago in another thread:
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2003 D2 FL S8. Irish Green Pearl/Beige. Solar sunroof, auto-dim mirrors, electric rear seat functions and extended leather. Ski hatch retrofit. Aftermarket reversing camera. DVB-T and XCarlink now removed as redundant. 2016 Volvo V40 T5 Cross Country (4WD) with ALL the toys including adaptive cruise etc. etc. Osmium Grey with Blonde/Charcoal leather interior. Polestar performance "optimisation". (Even rarer than a D2 S8!) Oh, and a brand new engine at just under 30,000 miles on the factory one! Finally: gone, but not forgotten..... 1998 D2 PF S8. Agate Grey/Platinum. Every option (I think) except electric rear seats, Tiptronic steering wheel, ski hatch, towbar & dimming door mirrors. e.g. Cruise control, NavPlus/TV, Bose, GSM, Xenons, Solar roof, Parking sensors, Alcantara/leather everywhere of course. (internal dimming mirror added later) 1998 (very early) Ford Focus 1.8 Zetec; ABS/TCS, Heated screen/mirrors, Aircon. Added Auto-dim mirror, Leather seats, Trip computer, Cruise control, OEM Ford SatNav with CD changer. And before that a lot of Rover 800s, a few oddities, a lovely Triumph Dolomite 1850HL with Overdrive and way back in my schooldays an Austin Seven aka Mini 850! Last edited by HPsauce; 10th December 2017 at 01:29 PM. |
#6
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Thanks mate I’ll give it a go, PFL has the same type of brake switch with 4 pins.
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#7
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My D3 exhibited similar symptoms a couple of times in London and I replaced the brake switch as I had read similar stuff but do you ever get poor starting when warm on the car ie refuses to turn over? If yes as well then it could very well be your Crankshaft Position Sensor on the way out which is what failed on mine eventually and cured that issue at the same time
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Confidence is the feeling you have before you know better . . . . Audi A8 D2 3.7 Quattro Sport 1999 FL - Melange 2nd Place Winner - A8-Freunde Annual German Meet 2012 at Edersee 20" x 9" Bentley GTC Wheels with 385mm W12 Front Discs & Bentley Caliper Covers, Front Lowered on Coilovers, Xenons, Combined DRLs and LED Foglights to modified OEM front fog lamp position, Alcantara/Leather, Full Black Alcantara headlining + pillars and blind shelf, Bespoke Flat Bottomed Sports Steering Wheel, Dark Myrtle Wood, Autodim Mirrors, Bose, Blinds, Digital TV, Ski Hatch, Modified rear exhaust section for extra V8 Burble Audi S8 D2 Final Edition 2002, Avus Silver with Red Leather Interior Tiptronic with Sport mode button, Sony rear entertainment package, Bose sound system, Audi Navigation Plus, 20 inch Final Edition alloys, Full Cat Back Stainless Milltek exhaust, giving a great V8 burble Audi A8L D2 4.2 Petrol with LPG - Ebony Black Audi A8L D4 FL 4.0T Petrol twin turbo - Havana Black Audi A2 1.6 FSi Sport - Dolphin Grey with Votex body kit and Red Leather Interior and some other A8's A8L's and Mercs |
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