2009 A4 2.0T EPC light on and a ton of codes all in one day

[Finalunity]

Today the weirdest thing happened to my wife's A4 Cabriolet. First let me state that I am new to this forum and my 2009 Audi A4 S-Line is completely stock with 67k.

So the first thing that showed up was the EPC light then the check engine light a minute later.
Immediately the car started running a bit limp and it didn't seem to want to shift into gear without feathering the gas pedal. It would just keep increasing with RPMS (40mph 4000 plus RPMS).

So my first step was to check the battery and the guys at AutoZone said that the battery was weak so I replaced it. That didn't fix it but it cranks faster now :-/

Next step read the codes (had to wait for a code reader from a friend).

Here is the list:
P0455
P0441
P2015
P2014
P2295
P0458
P0245
P2401
P0030
P0037
P2181
P0089

Is it me or does seem like way too many codes with too many systems to fail all at once? Could a bad battery cause a short in the system that is now telling me that I have to replace all these sensors?

Any help here is appreciated. Thank you.

[NODES2K]

ECU water damaged?

[Finalunity]

ECU water damaged?

I don't think so. Other than car washes and rain the car has not been through much but then again I'm not an expert.

How can I check if the ECU has water damage?

Thanks

[Jet08]

Those codes could be historic (old) so you need to clear them to verify current state of errors. A bad battery will not cause a short, bad as in old.

[Finalunity]

OK so I cleared the codes and then started the car. I for second there I didn't think it was going to start because it cranked for a while before it started.

EPC light came on right away and these codes popped up:

P2295 Fuel Pressure Regulator 2 Control Circuit Low
P0458 Evaporative Emission Control System Purge Control Valve Circuit
P0245 Turbocharger wastegate solenoid A input circuit low is below specifications
P2401 EVAP Leak Detection Pump Control Circuit Low
P0030 HO2S Heater Control Circuit Bank 1 Sensor 1

I'm so confused as to why so many systems failed at the same time.

[Silveravant]

All these codes and EPC/limp mode are most likely caused by a faulty 614 relay which is in the bottom of the ECU box in front of the windshield on the drivers side. Some people get this from water in the box. In my case I had no water, but when I replaced the relays (there are 2 614 relays and I was not sure which one was faulty) the problem went away and has not returned for at least 2 years. If you search for 614 relay you will find more information and perhaps a DIY.

[Finalunity]

All these codes and EPC/limp mode are most likely caused by a faulty 614 relay which is in the bottom of the ECU box in front of the windshield on the drivers side. Some people get this from water in the box. In my case I had no water, but when I replaced the relays (there are 2 614 relays and I was not sure which one was faulty) the problem went away and has not returned for at least 2 years. If you search for 614 relay you will find more information and perhaps a DIY.

WOW! That would be amazing! I found a video on how to remove the plastic covers and box and I'll take a look in there. Maybe even swing by the Audi/VW dealer and get a couple of relays.

I'll let you know what I find.

Thank you!

[Finalunity]

Well... after an exhausting wiper arm removal I finally got to the box. Replaced both relays and I still have the EPC light on with the following codes: P0458 P0245 P2401 P2295

Not a drop of water or any sign of water in the box btw.

This is driving me nuts on what it could be. I've read that it might be a TPS sensor or a crank sensor but these would put up a code I assume so why would one of those be the issue?

Any other ideas on what it could be?

Thank you.

[B7S3wannabi]

Blown fuse




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[EvolutionArmory]

Those are all electrical. You need to find out if any of those systems share a fuse, relay, ground or anything else electrical and start there.

[B7S3wannabi]

They all share the same fuses and relays in the plenum box. You need to check all the fuses since you already replaced the relays.


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[Finalunity]

Checked all the fuses in the fuse box. All are good. I pulled each one and visually inspected and used a test light.

Are there more fuses elsewhere? I don't see any under the ECU box where I replaced the two 614 relays.

Thanks again everyone.

[Finalunity]

They all share the same fuses and relays in the plenum box. You need to check all the fuses since you already replaced the relays.


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OK I didn't see it at first but now I found a couple of fuses under the wiring harness. Found a 15amp fuse that was blown and I installed a new one it blew again. It's in a tan holder as they're all different colors but I don't know what that circuit is for.

Anyone know what that circuit is?

I can post a picture if needed.

Thanks again

[B7S3wannabi]

OK I didn't see it at first but now I found a couple of fuses under the wiring harness. Found a 15amp fuse that was blown and I installed a new one it blew again. It's in a tan holder as they're all different colors but I don't know what that circuit is for.

Anyone know what that circuit is?

I can post a picture if needed.

Thanks again

How many threads are you going to create about your issue?
Send me a pm with your engine code and build date and I will tell you what that fuse is for.
I can tell you from just your error codes that one of those solenoids/pumps/valves is most likely the issue. So with a handful of fuses, you could disconnect one at a time and see if the fuse still blows. OR you could take and ohm meter to each one of them.
Taking a guess, I would say the LDP (leak detection pump) has shorted. Among all of those codes and what that fuse powers, a shorted pump motor would most likely draw the most current.

[Finalunity]

How many threads are you going to create about your issue?
Send me a pm with your engine code and build date and I will tell you what that fuse is for.
I can tell you from just your error codes that one of those solenoids/pumps/valves is most likely the issue. So with a handful of fuses, you could disconnect one at a time and see if the fuse still blows. OR you could take and ohm meter to each one of them.
Taking a guess, I would say the LDP (leak detection pump) has shorted. Among all of those codes and what that fuse powers, a shorted pump motor would most likely draw the most current.

My apologies for the second post... I was on my cell phone trying to upload a picture and I couldn't get it to work on this thread (I'll try to delete the other post).

I found this plug on the High Pressure Fuel Pump has a hard ground going back to that fuse:
IMG_20181013_215350.jpg

Fuse doesn't blow with that one unplugged but the car still runs. Pretty expensive part but I have to give it a try and play process of elimination to get this figured out.

[B7S3wannabi]

My apologies for the second post... I was on my cell phone trying to upload a picture and I couldn't get it to work on this thread (I'll try to delete the other post).

I found this plug on the High Pressure Fuel Pump has a hard ground going back to that fuse:
IMG_20181013_215350.jpg

Fuse doesn't blow with that one unplugged but the car still runs. Pretty expensive part but I have to give it a try and play process of elimination to get this figured out.

Great work. Sounds like you found your issue.


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[Finalunity]

Great work. Sounds like you found your issue.


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Is there a preference in what pump to get? There's a few manufacturers that make them.

Also I believe this is one of a couple of issues. I hope that's the only issue but when I started the car with the pump unplugged I still had other codes. But hey if I can take one down at time I'm a happy camper :-)

Thanks again for everyone's help. I'll post an update if that resolves my problem.

[B7S3wannabi]

You will most definitely have additional codes if the regulator is unplugged.
I believe oem is hitachi. I would stick with that.


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[Finalunity]

Been meaning to come back and thank everyone for their help.

All my codes went away once I replaced the High Pressure Fuel Pump.

Great forum