Fault codes
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Fault codes
Good day everyone I’ll try to make this quick 2007 a8 returned from a 600 mile round-trip check engine light came on that evening when I went to start it the next day the EPC light was on and it would hardly stay running scanned it and the following codes came up P0 300, P0087, P0458, P0498, P2257, P2294, P129B,P0102, P240 one, P0304, P0308, P0301 I know the last three are misfire codes just wondering what everyone thinks and what you would repair first thanks in advance. I will leave it to the Audi gods thank you again.
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Joined: Jan 2013
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From: Australia
Good day everyone I’ll try to make this quick 2007 a8 returned from a 600 mile round-trip check engine light came on that evening when I went to start it the next day the EPC light was on and it would hardly stay running scanned it and the following codes came up P0 300, P0087, P0458, P0498, P2257, P2294, P129B,P0102, P240 one, P0304, P0308, P0301 I know the last three are misfire codes just wondering what everyone thinks and what you would repair first thanks in advance. I will leave it to the Audi gods thank you again.
It’s possible the main fuel pump has failed or is failing.
What I would do to test this is to clear the codes, then jump the relay pins on the second pump in the tank to force it on then start the car. If the car suddenly comes good and has no codes, the main pump needs to be replaced.
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Fault codes
Thanks for responding, I looked online and the only thing I saw was right and left high-pressure fuel pump. Am I searching wrong? I know you said main fuel pump how would I search for that or is the right and left the main ones also when I scanned it check engine light went off. EPC stayed on even disconnected battery and reconnected EPC light won’t go off,
AudiWorld Member
Joined: Jan 2013
Posts: 306
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From: Australia
Earlier cars just use the electric pumps and have normal Multipoint injection. What I think is happening is that the electric fuel pump/s have begun to fail, this creating a lot of errors downstream with the high pressure system.
The reason I said to jump the secondary in-tank pump is because the system has redundancy built in.
The two pumps are capable of supplying the engine on their own. The main one works all the time when the car is running, the second one comes on for 30 seconds when the car starts to build pressure then only comes on to level the tank or above 3/4000rpm.
If you pull the secondary pump relay, jump the power wires (the two big ones) and then clear the codes and start the car and it runs happily, then you know the main electric pump is failing or has failed. If not, the issue is in the engine bay.
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sk88erguy
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Mar 16, 2006 05:53 PM
