Emission Service Rqd culprit - fuel pumps!
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Emission Service Rqd culprit - fuel pumps!
Thought I’d start this thread as there’s a ton of information regarding the Emission Service Required CEL but I couldn’t place reading about the cause that triggered mine. The background was as most others find, CEL comes on followed by message, then a quick zap with a diagnostic tool to reset. Autel was reading P0171 & P0174 codes (bank 1 & 2 running lean). My initial research into this pointed towards either vacuum leak or O2 sensors. I have recently installed some custom cat deletes and put the error codes down to the O2 sensors seeing more gas flow past them as the error would generally present itself during spirited driving. As the problem was becoming more persistent and the car has extended warranty, I booked a visit to the dealership. AM datalogger indicated ‘fuel pump running low’ and the freeze frame data showed fuel pressure @ 33psi instead of the required 50psi. Long story short, after 2 new fuel pumps the problem seems to have been cured! What I did find surprising was the 8 hour factory labor charge to replace the pumps! Not only does the tank have to get dropped but to do so involves removing the transmission and rear subframe. The cost of the extended warranty is starting to make a whole lot of sense now as I dread to think what this would have cost otherwise. Hopefully this might prove useful if anyone’s having the same problem and all the usual candidates are proving to be O.K when checked.
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Yes very interesting both pumps were low pressure. Just a guess but 2006 DB9 coupe? V8 vantage one pump, V12 two pumps. With the exception of later 13MY up have a single pump.
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Last edited by AngloCan; Jun 27, 2018 at 01:38 PM.
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and why I incorrectly put it down to the cat delete. Later it would illuminate almost immediately after resetting.I probably should have waited to post the cause as this morning the all too familiar CEL and message is back! I almost managed 20km before it returned! I’ll update again if it turns out to be anything other than the usual suspects.
Aston ownership is certainly a test of patience if nothing else...!
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The code became persistent. Initially it only seemed to occur whenever the car was driven using the paddles, which invariably mean’t the revs were somewhat higher
and why I incorrectly put it down to the cat delete. Later it would illuminate almost immediately after resetting.I probably should have waited to post the cause as this morning the all too familiar CEL and message is back! I almost managed 20km before it returned! I’ll update again if it turns out to be anything other than the usual suspects.
Aston ownership is certainly a test of patience if nothing else...!
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I have a 2012 V12 Vantage that just popped this error code up this weekend. 200 miles ago the car had a full service and it has a 2 year warranty on it. Is it OK to keep driving the car? Is this something that is serious enough to take to the dealership? Or can I have a local foreign car guy take a look at it? Slight problem is nearest dealership is 100 miles away. Any advice is appreciated. thanks
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Aston Martin db9 volante 2006
Hello, I have the same defect P0171 and P0174 on an Aston Martin DB9 Volante V12 from 2006 with the Autel had you fix the problem . The problem appeared after an oil change but there is no air intake. The tank had just been filled up. Best regards .
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The code became persistent. Initially it only seemed to occur whenever the car was driven using the paddles, which invariably mean’t the revs were somewhat higher
and why I incorrectly put it down to the cat delete. Later it would illuminate almost immediately after resetting.I probably should have waited to post the cause as this morning the all too familiar CEL and message is back! I almost managed 20km before it returned! I’ll update again if it turns out to be anything other than the usual suspects.
Aston ownership is certainly a test of patience if nothing else...!
I would be looking at the fuel pump driver modules first because they control the pump speed and consequently, the fuel pressure. In other words, fuel pressure is not controlled by the pumps running flat out and a pressure regulator returning unwanted fuel back to the fuel tank, the driver modules alter the pump speed to supply just the correct amount of fuel to the fuel rails to maintain the pressure required to maintain the mixture set by the engine management taking into consideration the load demand.
It would be highly unlikely ANYWAY that both pumps would fail partially, at the same time. 99% of the time, they would either run, or not at all.
My advice from now on would put the car on a rolling road/dyno and check the fuel mitures as the car goes through the rev range. Don't do a full power run, just keep an eye on whats going on with the fuel mixtures.
Afterthought..............I would assume they replaced the twin in-tank fuel filters whilst they were in there?
Last edited by 8Tech; Jun 22, 2021 at 03:37 PM. Reason: Pondering thoughts!
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