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General => General discussion => Topic started by: dazzawest1987 on 15 August 2012, 11:24
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hi all, im after a bit of advice. my boss has got a bentley continental GT, it's got a W12 twin turbo engine, which i know is the same the engine that VW put in the Phaeton so im hoping one of you may be able to help me. his engine management light is on snd come up with the fault code P2438, after a bit of googling ive found it seems to relate to a secondary air injection fault. there was a technical bulletin out about this but it has been carried out already. so if anyone could shed abit more light on this, likely causes ect. it would be really appreciated.
cheers
darren
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Buy a Haynes manual ;)
They fire hot air In to the engine to warm the cats up when cold , the pipes can become blocked or come
Lose on the drivers side I can't remember where they are as I haven't worked on a gt for a while but believe they run from the air box down by the front inter coolers
Check the pumps fuse but it's a job you need in front of you to diagnose tbh
But Vagcom reads the bentleys fully and you can run all the appropriate tests ect
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Do they do Haynes manuals for bentleys?
Fault code says bank 2, which I believe Is passenger side. Will check pipes and connections see off I can see anything
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Don't suppose you have a rough idea of where the sensor?
Cheers
Darren
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Don't suppose you have a rough idea of where the sensor?
Cheers
Darren
All I can remember the pump is down the o/s wheel arch , and there common for pipes coming of .
The Haynes manual I was pulling your leg about mate ,
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Don't suppose you have a rough idea of where the sensor?
Cheers
Darren
All I can remember the pump is down the o/s wheel arch , and there common for pipes coming of .
The Haynes manual I was pulling your leg about mate ,
(http://i1119.photobucket.com/albums/k624/spudboy6/e341c564.jpg)
Gt's the last one I done , see the round pump behind the o/s inter cooler , that's the pump and filter that run up an go near that silver foil on the engine then the plastic pipes run over to the rocker cover on the o/s o the top of my head ,
There are several sensors round the maf and bottom of the inlet manifold . But get in there with brake cleaner spraying looking for air leaks
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Briliant cheers mate, I'll have a look over it saturday
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was the technical bulletin replacing the vacuum hoses to the combivalves at the back of the heads? if not, thats where i'd be looking first
you might find this useful too, not sure how much of it translates over to the twin turbo http://www.volkspage.net/technik/ssp/ssp/SSP_268.pdf
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It was something to do with pipes :grin: don't know anymore than that to be honest. Will check all the pipes that I can see and get to, the code description says sensor circuit fault though, so think it maybe a sensor or wiring issue, will check on Saturday and see what I can see.
Cheers for the link will have a look at it
Cheers
Darren
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i didn't google the P code, i never trust those :grin: see if you can get a vag specific code out of it. if it is something in the circuit then you'll probably find this document more useful http://www.volkspage.net/technik/ssp/ssp/SSP_250.pdf
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P codes learnt that the hard way.
what the P code says , and what it actualy is ,,,,, the differance can be inpressive
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haha, really? i've got a vw dealer near me, i'll get my boss to take his car down there and get them to read the fault code quickly.
thanks for those documents topher, they'll be really usefull
cheers
darren
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They fire hot air In to the engine to warm the cats up when cold
Is this EGR or is there a seperate feed?
Only curious as most manufacturers have a injector spraying fuel into the CAT to aid heating and I can't work out how just firing hot air in to the engine would aid warm up as the exhaust would be much hotter than any kind of hot air that could be provided.... :undecided:
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the extra fuel is already there thanks to the warm-up enrichment (cold start/choke). the secondary air injection does just that, adds extra air after the exhaust valves. Bosch refer to it as thermal afterburning which sounds cool, but is rather dull :grin: its kind of like an egr system but is only active for about 30 seconds.
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for slick quick description of operation,
The secondary air system reduces
exhaust emissions in the cold starting phase.
During a cold start there is an increased
percentage of unburned hydrocarbons.
The catalyst cannot process this quantity as it has
not yet reached its operating temperature and a
mixture must be present from lambda 1.
The level of oxygen in the exhaust gases is
enriched by injecting air behind the exhaust
valves. This causes afterburning. The heat this
releases brings the catalyst to its operating
temperature more quickly.