Go Back  AudiForums.com > Audi Models > Audi A6
Multiple CEL codes on 2003 A6 3.0 >

Multiple CEL codes on 2003 A6 3.0

Audi A6 The mid-sized Audi A6 model offers more room to the driver and passengers over the A4 line.

Multiple CEL codes on 2003 A6 3.0

  #1  
Old 08-29-2011, 02:16 PM
1st Gear
Thread Starter
Join Date: Apr 2009
Location: West Virginia
Posts: 17
Default Multiple CEL codes on 2003 A6 3.0

Hello,
I am needing assistance on my 2003 3.0 A6, 160,000 miles, with multiple CEL codes I keep getting. They started recently and if I read them then erase, sometimes vehicle runs and idles great then the codes reappear and car idles badly and occasionally dies at idle.

P0346-Camshaft position sensor A
P0300-Random multiple cylinder misfire
P0301-Cylinder 1 misfire
P0302-Cylinder 2 misfire
P0303-Cylinder 3 misfire
P0304-Cylinder 4 misfire
P0305-Cylinder 5 misfire
P0306-Cylinder 6 misfire
P0171-System lean bank 1
P0174-System lean bank 2
P0102-VAF/MAF low input
P0492-Secondary air system bank 2
P0491-Secondary air system bank 1

The car idles rough and dies occasionally at idle, then becomes difficult to start.
I know this is a lot of codes at once, but what can I do to fix this. What needs replaced, and where are these defective pieces located? Could a bad cam sensor be setting off the misfire codes? Is the lean codes possibly due to a vacuum leak and where is a probable leak at? What is bank 1 or 2? How can you tell if timing belt is off?

Thank you for your help
 
  #2  
Old 08-29-2011, 03:59 PM
Jackmup's Avatar
2nd Gear
Join Date: Mar 2009
Location: New York
Posts: 1,227
Default

The two codes to pay attention to here are the CPS and the VAF/MAF low input. They most likely have wires in the same harness.

Is Your battery fully charged and in good shape?

Looks like it can't adjust the timing because it has no idea where it is with out the CPS. It can't adjust fuel without knowing how much air is coming in mass air flow sensor (MAF). They work together so it could be one causing the other.

Check the harness, connector to the camshaft Position sensor and to the Maf. Pull them off pinch the females closed and use a nail file to clean the males. apply di-electric grease and re-assemble.

Seems like you have a broken wire somewhere. check your harness to see if they have been burnt on the exhaust manifold or something. Start by checking behind the valve cover area on the passenger side, look for burns.

If you find one have someone solder and heat shrink it, Or you tube that and do it yourself. I wouldn't use a wire butt connector on wiring in these cars you may loose voltage and that's no going to help.

If wires look good, then you will need to test the sensors.
If sensors test good you will need to check the ECM connections and the ECM itself. I don't think you need to go that far though.


Bank 1 is the 3 on the passenger side
Bank 2 is on the Drivers side
I believe the Sensor A would be the first outside cam on the passenger side bank 1
Not a Timing belt because the codes point to electrical problems
Plus your lean that means not enough fuel, bent valves would cause way to much.
 

Last edited by Jackmup; 08-29-2011 at 04:03 PM.
  #3  
Old 08-30-2011, 07:19 PM
1st Gear
Thread Starter
Join Date: Apr 2009
Location: West Virginia
Posts: 17
Default

You are a wealth of knowledge and I thank you for the information. I checked the wires, harnesses and it appears that everything looks good. Connections in the harnesses I opened up are clean and shiny and they snap in good. The harnesses I looked at were located at the rear passenger side just under the MAF and I was wondering if the two identical sensors, each held in by a single T30 torx bolt, are these the CPS? How can I figure out which one is A? If that is a possible malfunctioning sensor? Is it the upper or lower sensor? I did unhook each of these sensors one at a time while the vehicle was running and I did not notice any difference?
The 2 attached pics shows:
1. The rear passenger side head area where I removed what I refer to as the lower sensor.
2. The sensor I removed from the mentioned location. Is this one of the CPS's?
I have since put the sensor back in place and am awaiting for your expertise in this matter.

Do I understand correctly that there are 4 CPS's on this engine?

Approximately 5 months ago, I had the coil packs replaced due to the recall by an Audi dealer, and I cleaned the MAF about couple months ago with MAF cleaner, it made it shiny and bright.
Don't know if this is pertinent or not, but I thought I'd mention it.

Thank you once again.
 
Attached Thumbnails Multiple CEL codes on 2003 A6 3.0-100_2849.jpg   Multiple CEL codes on 2003 A6 3.0-100_2850.jpg  

Last edited by mekyjesy; 08-30-2011 at 07:24 PM. Reason: left out info
  #4  
Old 08-31-2011, 06:38 AM
Jackmup's Avatar
2nd Gear
Join Date: Mar 2009
Location: New York
Posts: 1,227
Default

I found that the reason so many sensors fail in these cars is because of a loss on continuity in the terminal connectors. They may look clean but the female side relaxes and you need to tighten them up. Un-connecting and reconnecting without tightening usually preludes a sensor failure.

If all wires are good then you will need to test these sensors
In order to test them yourself and diagnose this car your going to need a Bentley manual, a multi tester and Vag-com.

The bentley will tell you how to test these using the multi meter for resistance.
The Vag-com will get you in to check for codes.

Without any of that, My guess would be that the CPS is bad and the Computer is throwing a MAF code because it rhymes with lean problems.
All of the other codes are a symptom of the underlying problem.

Don't bring it to Audi, They can only help you empty your wallet.

I order my parts from partsgeek.com and ecstuning.com with good success.

I don't have my manual with me to verify the position of CPS-A.
I am guessing that it is the outside of bank 1 on the back of the head by the firewall.
I try and look it up later
 
  #5  
Old 09-06-2011, 12:26 PM
1st Gear
Thread Starter
Join Date: Apr 2009
Location: West Virginia
Posts: 17
Default

I went through and tightened up all the connectors. I tried to trace the wires, but I can only follow them back a few inches and they join another wire bundle and go down along the back of the engine towards the tranny. All wire bundles and sheathing I can see appear to be intact. Is there a way to test these wires for continuity? Where is the other end of them and can I identify each specific wire if I can get on the other end of it?
I replaced the CPS that was supposedly giving me the P0346 code (pass side, intake sensor, located in the upper position of the two CPS's) My wife then drove vehicle about 250 miles each way over two days, and it would occasionally stall on the highway, it would have to sit for some time, then it restarts. It was still stalling and rough idling too with sometimes a EPC light comes on and loss of power. The EPC is intermittent. It seems to act up on extended trips, (say 20 miles or more at a time, then it can either die on its own or if you stop and shut it off, it is difficult to restart) Last night I swapped the new CPS into the position of the exhaust and put the one that was in the exhaust position into the intake position, re tightened the connectors, cleaned the MAF.
Today I drove the car about 25 miles to read the codes at Advance Auto Parts. I have these codes now:

P0346 CPS A Bank 2 (same as I had before)
P0300 Random misfire (same)
P0171 Bank 1 system too lean (same)
P0174 Bank 2 system too lean (same)
P0322 Engine speed input circuit no signal (new)
P0102 MAF A circuit low input (same)
P0113 intake air temp sensor 1 circuit high temp input (new)

I erased the codes and drove it home with no power/stalling/idling/ECP light, or CEL code issues...yet.

Could my engine speed sensor be bad?
I'm sorry to keep bothering you, but other that tightened my connectors, I don't know how to troubleshoot the wires themself.

Thank you again
 
  #6  
Old 09-07-2011, 11:22 AM
Jackmup's Avatar
2nd Gear
Join Date: Mar 2009
Location: New York
Posts: 1,227
Default

This is long and a lot of info but I'm going to approach this a s your a smart beginner. I'm going to try to explain what these things do, what the codes are from and why I think you have a bad wire, no power or short to ground.

Hold off, stop replacing parts; we need to find the cause.
Whether or not you are a mechanic or aspiring to be one you need to decide to buy some tools or bring it to the shop. if your replacing electrical parts and they still don't work then you have a power supply issue.

You'll notice it keeps pointing at wiring


bad fuse
broken wire, short to ground or to positive
bad ECM

considering you own an Audi with 160K, I'll assume You'll be fixing this sucker yourself.
(otherwise buy a new one because the mechanic's bill will be the same)
At this point you need to scan it with a VAG-COM.

Either find someone with one
Buy it for $200 from Ross-tech (you need a laptop also)
There is a way to make a ebay cheapo work for $50 but I worry that it won't work when I really need it. Contact "Midnitoyl" he knows how to make the ebay one work.

You will also need a repair manual It's A CD Rom or download; bentleypublishers.com

The generic code reader that Advance has can not read all of the codes, You are missing part of the picture.
It also can not display real time data as the engine is running so you can not follow your sensors and see whats happening.

For continuity all you need is a decent multimeter; sears,advance or any electric isle. One that beeps when you have continuity is best.

Wire chasing is a "PITA" because the closer you get to the ECM the more wires join the bundle. To top it all off I'm color blind-sucks for me.
before you start chasing you need to think of places that would damage the wire (if that is your problem... it might not be but you need to rule some things out ) Look along the exhaust manifold, get a small mirror and peek behind the engine. If you see a pinched area;tug on it a little and see if anything changes;tugging will either make it better or worse. You will either pull the wire apart or away from what it is grounding on.

To chase them you might want to Study the wiring diagram available in the Bentley manual for your car- bentleypublishers.com but it's very confusing.
Basically you want to disconnect the battery, probe the red into one side of the wire than probe the black into the other and read the continuity.
you can not have an electrical part in between your probe points or voltage traveling through your line. Try it on a spare wire. probing the wire is Kindergarten stuff finding the other end of the wire can be a needle in a haystack sometimes. Figuring out what the wire does makes men from mice.

This site can definitely steer you down the correct path but you need to supply as much info. as you can and you'll need to read through the manual and posts to learn about these cars.

Before you start

In general I found any little rubber seal or tube tends to deteriorate at 90K, keep that in mind as your working and order replacement before you touch and break. vac lines and gaskets etc. I don't want you to pull stuff apart and create more problems. Have vacuum line on hand.

All of your sensor connections need to be cleaned, tightened/pinched and di-electric grease applied every 30K or everytime you disconnect them. have cable ties available in case you snap/break the lock of the connector when separating it you can install a cable tie around it to hold it together tight.

I'm telling you this because all of my problems on my two cars originate from bad rubber parts and faulty connections that made a sensor fail. You'll notice people will say I just replaced my spark plugs and I get multiple misfires.That's because they removed the coil packs and reinstalled without cleaning and tightening and lost the connection; It's that critical.-These are not Chevy's that's for sure.


ALL OF THAT SAID

It looks to me that the low input to your Mass Air Flow sensor, Cam Position Sensor, Engine speed senor, Intake Air temp sensor all need to be investigated / tested. the MAF measures the amount of air coming into the engine sends a signal to the ecm which in turn sends a signal to the throttle body and injectors and mixes the corresponding amount of fuel with it. Meanwhile the Knock sensor listens for pings and advances retards your timing but in order for it to do that it needs to know where your cam is via a signal from the cps. then it compares that with the signal from your engine speed sensor. The IAT determies if your car needs to be choked or not to start. Test your MAF It is located under a sort of triangular 12" cover on the left side by the air filter and is a round part in the intake line. looks like this
02 2002 Audi A6 Quattro Air Mass Meter - Air Intake - Bosch, Hitachi - PartsGeek The Maf is an easy place to start/get to If it doesn't have power I'll bet neither do the others.

So if you're still with me

The first thing I think of is what do these parts have in common

1) The ECM powers and controls them. Let's hope it's not bad, It will be the last thing we check.
2) They all need wires, without power they will not work.
3) All of your problems involve control of fuel ratio and timing and they all need each other to do this correctly.

The only other thing that might sort of cause all this commotion is poor fuel pressure and it just so happens that your MAF sensor gets it's power from the fuel pump relay, but your fuel pump is working so...

Poor fuel pressure could be caused by a Bad pump or pump wiring, clogged filter, or regulator. This can be tested at the fuel rail with a fuel pressure gauge.


Lets take one at a time

Wiring

1) Get a mirror a step stool and dive into that engine don't rip wires out into spaghetti messes, but look for a possible pinch or burn point. You can use a long thin object like a long screw drive to move the wire loom around. Just inspect don't cut. If you see something rubbed out then go further. so if you have a pinch point you connect the continuity tester to either side of the supposed break an inch back or so if it has poor continuity repair the wire with a solder connection. You can not be a lazy and butt connect it it must be an great connection. Spend some serious time in there looking. You are the only one that can pinpoint that.

P0113

the IAT intake air temp sensor.

OK you replaced it so it's new and still not working!!!

good news this means you either have a short to ground or to Positive in your harness.

I would spend a few hours now looking for a broken wire. not a mere glance you need to search. I would start behind the engine


P0102

1) Test your MAF sensor, You need a Bentley manual and a multitester.
The procedure is listed in the bentley very clearly for testing voltage at the harness.

I can't list the entire procedure but I'll give you this for now to test the relay
-unplug the MAF connector, do NOT disconnect battery for this test
-flip the connector so the locking mechanism(plastic hump) is down
-with the hump down the pins are numbered 1-5 left to right
-hook your multimeter blackwire to a good ground set to DC VOLTS
-hold the red wire to the number 2 pin only and have a helper turn the ignition switch to start, it's OK if the car starts but turn it right off if it does.
-you should have battery line voltage to the number 2 pin. It should be about 11-14 Volts depending on how drawn down the battery is.
If you don't have that then the wire is broken between the no2 and the fuel relay or there is a problem with a terminal that the relay is plugged into. It's not the relay because your fuel pump is somewhat working, But as fuel pumps go they tend to heat up after driving 20minutes and die causing the car to stall. After sitting in the cold fuel for a while they work again.


Next look Vacuum leaks or way air is getting into the intake manifold without going past the MAF sensor. Any un-metered air will create problems; Broken vacuum lines or intake pipe. You can by a cheap vacuum tester but at 160K you should replace every vac line anyway. The line is cheap and it's an easy job. I buy my line from ECStuning.com but there site is down today. Get the braided line like oem. Advance won't have it but Audi and BMW would.

But vacuum leaks don't cause all of those codes.

P0346

The cam shaft position sensor A bank 2.

Position A bank 2 is the Drivers side bank 1 is passenger , 2 Driver
I know in my previous post I wrote passenger but it only said sensor A not A2 so you need to do that again.

position A bank 2 is located on the back side of the cylinder head on the drivers side

That's where the vag-com earns it's keep

swap it with the used one you just took out

Again if it's new and not working....wires or power supply

The ecm uses info from this sensor compares it to engine speed(crank sensor) in order to mechanically adjust the timing. So your CPS and CSP sensors need each other and they are both sending codes but not all of your cam sensors are sending codes. so the others must be good. I hope.

next unplug the connector
place the multimeter on volts again
with the lock hump part down stick the red lead in the outside right terminal and the black in the outside left and turn on the key you should get 5.0Volts
if you get nothing your not getting power or you have a bad ground. Either way I would be then searching for a broken wire. either the power supply is broken or the ground wire is broken.

P0171 and P0174

These codes are telling you that the cylinders are getting either too much air or not enough fuel. If it can not read the MAF it can not adjust the fuel ratio and will run like crap. If it does not have enough fuel pressure then that might cause this as well but I would have expected different codes to pop up then the ones you're getting. This will stop when we find the problem, it is an affect of the problem. This is determined by the O2 sensors at the cats on both sides so we know it's not just one bank it's both.


P0300

Just tells me multiple cylinders are misfiring. They should be misfiring with all of those sensors off line. This will stop when we find the problem. It is an affect of the problem. multiple doesn't really tell us both banks but with a vag-com you would be able to watch them as they misfire and see who's naughty or nice.


P0322

Engine speed sensor

on the firewall there is a bracket holding 4 terminals
the third from the left should be the Engine speed sensor / crank sensor

to test disconnect it
you will be working with the sensor this time so the male pins not females
holding the terminal with the tab to the left the pins will be 1,2,3 left to right
set the multimeter on ohms / continuity
check the resistance between 1 and 2 it should be 0.7 to 1000 kOhm
if not it's bad anything other it's bad. replace it.


My guess

Wires/connections these sensors all get their power from differing places but probably have a wire loom or a ground wire in common.

ECM You need a Vag-Com to even think about testing it but I would check the terminal connectors and make sure the box is water tight. it is on the drivers side under the plastic cover by the windshield.

Fuses- wouldn't that be great!

let me know how you make out
 

Last edited by Jackmup; 09-07-2011 at 11:37 AM.
  #7  
Old 08-18-2018, 08:35 PM
1st Gear
Join Date: Aug 2018
Posts: 1
Default

Originally Posted by mekyjesy View Post
I went through and tightened up all the connectors. I tried to trace the wires, but I can only follow them back a few inches and they join another wire bundle and go down along the back of the engine towards the tranny. All wire bundles and sheathing I can see appear to be intact. Is there a way to test these wires for continuity? Where is the other end of them and can I identify each specific wire if I can get on the other end of it?
I replaced the CPS that was supposedly giving me the P0346 code (pass side, intake sensor, located in the upper position of the two CPS's) My wife then drove vehicle about 250 miles each way over two days, and it would occasionally stall on the highway, it would have to sit for some time, then it restarts. It was still stalling and rough idling too with sometimes a EPC light comes on and loss of power. The EPC is intermittent. It seems to act up on extended trips, (say 20 miles or more at a time, then it can either die on its own or if you stop and shut it off, it is difficult to restart) Last night I swapped the new CPS into the position of the exhaust and put the one that was in the exhaust position into the intake position, re tightened the connectors, cleaned the MAF.
Today I drove the car about 25 miles to read the codes at Advance Auto Parts. I have these codes now:

P0346 CPS A Bank 2 (same as I had before)
P0300 Random misfire (same)
P0171 Bank 1 system too lean (same)
P0174 Bank 2 system too lean (same)
P0322 Engine speed input circuit no signal (new)
P0102 MAF A circuit low input (same)
P0113 intake air temp sensor 1 circuit high temp input (new)

I erased the codes and drove it home with no power/stalling/idling/ECP light, or CEL code issues...yet.

Could my engine speed sensor be bad?
I'm sorry to keep bothering you, but other that tightened my connectors, I don't know how to troubleshoot the wires themself.

Thank you again
hello sorry to hear your having issues, I had the same problem in my other b6 it was throwing codes for cam sensor faults
have you checked your CRANK shaft position sensor and turned out to be the one for the crank. But it would like you said stall and then take some time to be able to restart
 
Related Topics
Thread
Thread Starter
Forum
Replies
Last Post
phdnpcpi
Audi A3
0
04-16-2014 09:27 AM
DJLishis
B7 Models
2
12-18-2013 01:24 PM
JPizano23
Audi A8
8
09-23-2011 11:36 PM
B6 Models
1
10-22-2010 11:47 AM
jangalang
B5 Models
0
11-10-2009 12:17 PM


Thread Tools
Search this Thread
Quick Reply: Multiple CEL codes on 2003 A6 3.0


Contact Us - Archive - Advertising - Cookie Policy - Privacy Statement - Terms of Service

© 2019 MH Sub I, LLC dba Internet Brands

We are a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for us to earn fees by linking to Amazon.com and affiliated sites.