Question about Audi A4

2 Answers

2001 A4 V6 ECU# 3B0 907 551 BP.Got DTC code P0605 about a month ago.No problems,CEL went away after a couple of run cycles.Then yesterday got CEL again,same code.Thought I'd just run it out,it was working perfect.Then shut it down for 10 minutes and wouldn't start.No self check CEL when ignition turned on.Pulled one of the fuses for the module and then pushed it back in. CEL self check popped back on and car started perfect.Now everytime I try to start it when it's hot same thing happens.I pull the fuse,wait a minute,put the fuse back in and away we go.Car runs exceptional.Does this sound like a bad relay?A weak battery?Or could it actually be a bad ECU?I've checked as many connections as I can find and they all seem good.ECU itself is spotless and no water has ever gotten in there.If it's a bad ECU will one with a # ending in BQ work with my car that ends in BP?I'm checking codes with a generic code reader.Don't have access to Vag-Com.

Posted by on

  • 1 more comment 
  • Jun 17, 2009

    Thanks for the reply.What about relay?Battery?The code only popped when first starting car,not while running.To me it seems that when I shut power off to the ECU by pulling the fuse it reboots.Once it's up and running car is good as gold.I know where there is a BQ ECU in good shape.60K on it.Will I be able to drop it in or have to go to the thieves at Audi to have them initialize it.I live a long way from the dealership.

  • Jun 17, 2009

    Stealership is right!!..I don't go there unless it's absolutely the last resort.I'm in Canada and Audi has a license to print money.The only thing I worry about with dropping in a new ECU,is the immobilizer.

    This has only seemed to come on since the weather finally got warm.This morning when the car was cold it started without pulling the fuse.But after a 20 minute drive and quick stop it happened again.It's parked now,and I expect it will start right up in the morning.I'm still not convinced that it's not a low power situation or something that causes the ECU to not boot up.Low battery voltage maybe?I know that they can be sensitive to low voltage.It's just so difficult to diagnose out here in the sticks.

    Many thanks.I'm gonna leave this Q open in case someone who has seen the exact problem before gives me the 'Magic Answer' that will cost me nothing to repair.But I'm with you,that it probably is a bum ECU.

  • Jun 17, 2009

    Good answer from rogrrabbit.Thanks my man!!.Anyone else have a thought on this problem?



2 Answers

  • Level 2:

    An expert who has achieved level 2 by getting 100 points


    An expert that got 5 achievements.


    An expert whose answer got voted for 20 times.


    An expert who has written 20 answers of more than 400 characters.

  • Expert
  • 174 Answers

It seems, all fuel caps are vented, and they can go bad. When the vent isn't operating properly, no air can get into the tank to replace the area where the fuel was before it went through your pump and fuel system. If there's no air coming in, it will create a vacuum that will eventually overpower the pump, and you won't get any fuel. I've also come across these kinds of issues with my car, so while it's admittedly different, the issues were close to the was always something.

Someone recently recommended grabbing the electrical schematics and checking on the grounds to make sure they aren't corroded, because a poorly grounded electrical system will wreak havoc on an ECU. Again, I could be a million miles away and dead wrong, but it's a free/cheap fix to look and clean them up.

good luck.

Posted on Jun 17, 2009

  • Level 3:

    An expert who has achieved level 3 by getting 1000 points


    An expert that got 10 achievements.


    An expert that got 5 achievements.

    Vice President:

    An expert whose answer got voted for 100 times.

  • Master
  • 986 Answers

This is telling me that you need a new ECU, 200 bucks can buya used one. The one ending BQ should work fine as long as its in good repair. I see the Generic code LOL it would be better to have the Audi reader for better results but this will work.

Posted on Jun 17, 2009

  • Roger Campbell
    Roger Campbell Jun 17, 2009

    Yes it should drop right in. The Battery is not the problem because you can start it. The relay is not an issure. I feel the new ECU should solve the problem. The stealerships may be able to give you an insight of the correct part from a factory code reader. Good Luck.

  • Roger Campbell
    Roger Campbell Jun 17, 2009

    Thats cool good luck



1 Suggested Answer

  • 2 Answers

SOURCE: I have freestanding Series 8 dishwasher. Lately during the filling cycle water hammer is occurring. How can this be resolved

Hi there,
Save hours of searching online or wasting money on unnecessary repairs by talking to a 6YA Expert who can help you resolve this issue over the phone in a minute or two.

Best thing about this new service is that you are never placed on hold and get to talk to real repairmen in the US.

Here's a link to this great service

Good luck!

Posted on Jan 02, 2017

Add Your Answer

Uploading: 0%


Complete. Click "Add" to insert your video. Add



Related Questions:

1 Answer

Speedometer dont work

which engine, 1MZ? what? the engine dictates the ECU the ECU dictates what scan tool works this year.
what country, not stating that ,makes all answers wrong.
so as always, i post from USA , answers

The speedo on 95 series cars have a VSS,
and if it is dead, the PCM will be glowing the ECU and very unhappy,

so l mr. ABS 100x angry...too.. Ignore ABS for now;.
as they say first things, first.
you turn key , to on, CEL glows, (must) means PCM happy.(self checks)
you start car, the CEL goes out and stays out , does it? no i bet.
you drive, and CEL comes on , you insert the diagnostic, jumper (non IMZ engine)
and bingo CEL flashes out code for VSS dead?

code 9, code 42? others?
post your DTC error code and we CAN fix it.
OBD1: engines.

ok , id fix the speedometer first.
sure would.
bad cable? did you test and check the cable yet?
i looked up your car at so could you.
VSS is manditory for many ECU/PCM /TCM and ABS functions.
your car i think is USA car, is it? , and if YES< then is OBD2 compliant?
see list of cars below that are, (early OBD2)
so if it is , scan it after driving say 30 miles, or 5miles fast.
got P0500 that is a dead VSS.
fix speedo. now.
any scan tool made for OBd2 works on IMZ engine, here, state side.

data: OBD2: cars.
1994 vehicles equipped with the early OBD II systems include Buick Regal 3800 V6, Corvette, Lexus ES3000, Toyota Camry (1MZ-FE 3.0L V6) and T100 pickup (3RZ-FE 2.7L four), Ford Thunderbird & Cougar 4.6L V8, and Mustang 3.8L V6.

1995 vehicles with OBDII include Chevy/GMC S, T-Series pickups, Blazer and Jimmy 4.3L V6, Ford Contour & Mercury Mystique 2.0L four & 2.6L V6, Chrysler Neon, Cirrus and Dodge Stratus, Eagle Talon 2.0L DOHC (nonturbo), and Nissan Maxima and 240 SX.

Dec 18, 2013 | 1995 Toyota Camry

1 Answer

My Geo Tracker runs rough at idle replaced 02 sensor,plugs rotor,cap and wires I started it and it ran OK for a couple of seconds and went right back to running too rich is this because of the air val

95 , 16valve ? engines, says so on top of engine valve cover.
all that is last.
key on, CEL glows? if not fix that first
key on, does CEL go out, running, ? if not pull the ECU DTC codes
using a paper clip.
The MAF is the air valve. Mass Air Flow sensor.
type MAF in the search box, vast ways to test it , cheap and easy.
ever do the 60k tuneup,
you skipped , filters, and new timing belt.
if the belt slips , spark timing goes way off, did it?
and compression drops from 170 to 100; classic symptoms....
the order is.: 1,2,3
1: good engine, "compression"
2: good spark, is the timing still at spec. as the under hood sticker shows>
3: fueling.

Feb 18, 2013 | 1995 Geo Tracker

1 Answer

2001 Toyota Sienna CEL displayed code P1150 & P0420 what could be the problem

Mine is a 2001 Sienna LE. I got the P0420 code and the dealer want to replace an engine control computer for $1600. I've found posts that say you can replace your oxygen sensors, which still costs around $100 each. The P0420 seems to be emissions related. When my check engine light comes on, I run the highest grade, no ethanol gas, and usually within a couple of tanks, the light goes off again. The last time it happened about 2 wks ago, I put in the 93 octane no ethanol premium and a can of Seafoam and within a half a tank, the light went out. Your problem might be more serious, and I don't know what the 1150 code is, but so far that's worked for me.

May 17, 2012 | 2001 Toyota Sienna

1 Answer

2005 pontiac sunfire DTC Code P0455, had a similar problem 2 mos ago but DTC Code was P0496? CEL just came on yesterday hadn't been on in 2mos?

Okay ,Reason I ask is some guys get the codes read but dont know what the code is traslating a problem.So do you know what these codes mean?

Mar 07, 2011 | 2005 Pontiac Sunfire

1 Answer

ABS and ESP lights on all the time. I bought Audi A4 B6 2004 only two months ago. It started in heavy rain.

The ESP system means the Electronic Stability Program. If the ESP & ABS lights on the dashboard permanently the ESP & ABS system is faulty. You must access the ESP & ABS Electronic Control Unit (ECU) memory for pull out all DTC (Diagnostic Trouble Codes), using diagnostic equipment connected to the data link connector of the car (placed in dashboard, under a plastic cover above the ashtray). Then you will be full informed about bad pieces (e.g.: front right wheel abs sensor interrupted, ...). After bad pieces replacement you will be able to erase all faults memored by ESP & ABS ECU, in other words reset the ESP & ABS system and turn off the warning lamp on dashboard.

Dec 31, 2010 | 2004 Audi A4

1 Answer

2002 Ford Escape (V6) P0401 P0402 nightmare

Sounds like you have a vacuum leak, a problem with the wiring, or a bad PCM. Check wiring for pinched, chafed, pierced, or broken wires. Make sure vacuum supply is good, and not collapsing when the vehicle is running. Beyond that, a trip to the dealer may be in order.

Jul 21, 2009 | 2001 Ford Escape

3 Answers

2003 Audi A4 1.8T Check Engine light on

The CEL means there is a Diagnostic Fault Code stored in the Engine Control Unit. There are 1000's of DTC's, so you will need to have it read by a Code Reader. Auto Parts stores like Auto Zone, Pep Boys, perhaps even Advanced Auto often will read the code for you; but by law they cannot clear the codes. Many codes do not cause drivability problems, severe ones will trigger the ECU to run in a Limp Mode, which would require repair work before any trip longer than a few miles. Hope this is helpful.

May 31, 2009 | 2003 Audi A4 Cabriolet

1 Answer

Check Engine Light comes on and off w/ P0304 code

this may be a defective fuel injector or a defective PCM (powertrain control module).

May 30, 2009 | 2000 Dodge Dakota Quad Cab

1 Answer

Will not start;will crankover

Step 1. Find a OBDII scanner (OBD stands for On-Borard-Diagnostics). Find out what DTC code (or codes) are stored in the ECU (DTC = Diagnostic Trouble Code, and ECU = Engine Control Unit - it's the computer which manages engine operation).
Step 2. After you find out which code is stored in the ECU, go to and register your veh (by VIN). Afterward, you can navigate the Hyundai Service Site to find out what system is giving you problems, the diagnosis procedure and what may be needed to fix it.
Nuff said... Let me know what you find.

May 30, 2009 | 2001 Hyundai Accent

Not finding what you are looking for?
Cars & Trucks Logo

Related Topics:

136 people viewed this question

Ask a Question

Usually answered in minutes!

Top Audi Experts

Colin Stickland
Colin Stickland

Level 3 Expert

22326 Answers


Level 3 Expert

81294 Answers

Thomas Perkins
Thomas Perkins

Level 3 Expert

14423 Answers

Are you an Audi Expert? Answer questions, earn points and help others

Answer questions

Manuals & User Guides