Technical help, Coolant temp

[Spirare]

To begin with. I am experienced with the B5 2.8L (Passat). I do all my own maintenance.
This past summer I bought a used 3.0L B6 Avant, 6spd. LOVE the car and got a super deal on it.

Saturday I did the Timing Belt. Everything went fine. Did timing and waterpump, rollers and tensioners. Took about 8 hours start to finish.

The heat works great. I bled the system down correctly.

The car ran for about 3 hours with no issues since thren. The needle on the temp gauge is dead center. The car runs perfectly.

Why I'm writing? I had to go to the store for beer and ice cream. The car had been sitting cold all day. I started it up to go. After about a mile of going 40mph I passed the speed limit sign and got into it. At 75 the CEL came on.

Plugged in the trusty lap top and these are my codes:

19497/P3041 - Powertrain Databus: Implausible Engine Temp. Message from Inst. Panel

16805/P0421 - Warm Up Catalyst; Bank 1: Efficiency Below Threshold

16815/P0431 - Warm Up Catalyst; Bank 2: Efficiency Below Threshold

16409/P0025 - Can't find this code anywhere

Obviously it failed for readiness on numerous monitors. (ox heating, ox sensors, SAIP, EVAP, CAT)

I cleared the codes and put the car to bed for the night. I got up and came to work this morning and the CEL did not come back on. I drove it conservatively...

It should be noted that last week I thumped the underbelly pretty hard on some ice leaving the drive way. I may have smacked the flex bellows.

Long and short... the FIRST code is the one that I'm concerned about. Given that I recently had the whole clip off the car I'm thinking I may have a loose connection. I do not have a Bentley for this car so I'm not positive which connections I should be looking at. The only ones I could check in the cold and dark last night were the connections for the fan. They are fine.

I guess I'm hoping that someone with better knowledge of the 3.0L can point me in the direction of which connectors to check (hopefully without pulling the clip again). I will entertain the notion that the CTS is bad but I need check the appropriate connectors first. I may also have an exhuat problem but I would expect that all these codes stem from the same problem (a loose connection).

Any help you can offer is appreciated. TIA!

[Spirare]

never got a response on this...

The problem persists. Anyone?

I'm now getting random misfires on the passenger side as well. I'm starting to think it's a bad O2 sensor or bad CAT. I was thinking SAIP but that should cause issues on both sides.

[old guy]

Here is what the Bentley has to say about the last code:

SAE VAG Description
P0025 16409 "B" Camshaft Position - Timing Over-Retarded Bank 2
N208 - Camshaft Adjustment Valve 2
Solenoid valve for camshaft adjustment checking
Valve train servicing

Your CEL came from the P0421/P0431. They are generally associated with bad catalytic converters. It could also be the rear O2 sensors but usually it is from the Cats. Your coolant temperature sensor is on the back of the motor so I doubt it is a loose connection. Here is where it is on a 2.8. Clicky click I believe the 3.0 is the same. If you haven't already done so you should clear all codes and see what comes back. Your misfires could be coming from a coil pack going south.

Good luck!

[Spirare]

Here is what the Bentley has to say about the last code:

SAE VAG Description
P0025 16409 "B" Camshaft Position - Timing Over-Retarded Bank 2
N208 - Camshaft Adjustment Valve 2
Solenoid valve for camshaft adjustment checking
Valve train servicing

Your CEL came from the P0421/P0431. They are generally associated with bad catalytic converters. It could also be the rear O2 sensors but usually it is from the Cats. Your coolant temperature sensor is on the back of the motor so I doubt it is a loose connection. Here is where it is on a 2.8. Clicky click I believe the 3.0 is the same. If you haven't already done so you should clear all codes and see what comes back. Your misfires could be coming from a coil pack going south.

Good luck!

I cleared last night and the CEL isn't back yet. That said I'm sure that the other codes are but the 19497 isn't.

The misfires are on 4,5 and 6. If it is the CTS I should be getting symettrical errors. Since I'm getting assymetrical erros I'm really leaning toward it being the passenger side CAT. I'm going to log data on the CTS to make sure it is working correctly and if it is go after the CAT on the passenger side.

I spoke with my tech guy and he is leaning toward CAT as well. Fortunately I have two CATs in my garage from a 2.8L ATQ. The exhaust should be the same diamater right? I will just get one of them welded in if so. Thaks for your help.

[diagnosticator]

I'm skeptical that the cat is the cause of the misfires. There is no feedback from the post cat O2 sensor that effects fuel mass injected, the post cat sensor only evaluates cat functional efficiency.

[old guy]

Agreed. A bad cat shouldn't cause misfires, just increased emissions.

[Spirare]

Good points both. All I can do at this point is chip away at it anyhow. The kicker is the car is running strong. I haven't NOTICED the misfire. It is a stumble on cold start if anything.

[Spirare]

Update:

Last night the car went into limp. Misfiring like crazy.

Here are my vag pulls starting from two weeks ago. The bulk are from last night:

VAG-COM Version: Release 311.2-N

Control Module Part Number: 8E0 909 559 D
Component and/or Version: 3.0L V6/5V G 0003
Software Coding: 0016711
Work Shop Code: WSC 63351
7 Faults Found:
19497 - Powertrain Databus Implausible Engine Temp. Message from Inst. Panel
P3041 - 004 - No Signal/Communication - Intermittent
16684 - Shareware Version. To Decode all DTCs
P0300 - 008 - Random misfire - Intermittent
16688 - Shareware Version. To Decode all DTCs
P0304 - 008 - random misfire, cylinder 4 - Intermittent
16690 - Shareware Version. To Decode all DTCs
P0306 - 008 - random misfire, cylinder 6 - Intermittent
16689 - Shareware Version. To Decode all DTCs
P0305 - 008 - random misfire, cylinder 5 - Intermittent
16815 - Shareware Version. To Decode all DTCs
P0431 - 001 - Warm Up Catalyst Efficiency Below Threshold (Bank 2)
16805 - Shareware Version. To Decode all DTCs
P0421 - 001 - P0421 Warm Up Catalyst Efficiency Below Threshold (Bank 1)
----------------------------------------------------------------------------------



The below were the codes I pulled last night:

First pull

VAG-COM Version: Release 311.2-N

Control Module Part Number: 8E0 909 559 D
Component and/or Version: 3.0L V6/5V G 0003
Software Coding: 0016711
Work Shop Code: WSC 63351
5 Faults Found:
19497 - Powertrain Databus Implausible Engine Temp. Message from Inst. Panel
P3041 - 004 - No Signal/Communication - Intermittent
16815 - Shareware Version. To Decode all DTCs
P0431 - 001 - Warm Up Catalyst Efficiency Below Threshold (Bank 2)
16805 - Shareware Version. To Decode all DTCs
P0421 - 001 - P0421 Warm Up Catalyst Efficiency Below Threshold (Bank 1)
16684 - Shareware Version. To Decode all DTCs
P0300 - 008 - Random misfire - Intermittent
16687 - Shareware Version. To Decode all DTCs
P0303 - 008 - random misfire, cylinder 3 - Intermittent

---------

Cleared the above and reread, below is the second pull:

VAG-COM Version: Release 311.2-N

Control Module Part Number: 8E0 909 559 D
Component and/or Version: 3.0L V6/5V G 0003
Software Coding: 0016711
Work Shop Code: WSC 63351
2 Faults Found:
16684 - Random/Multiple Cylinder Misfire Detected
P0300 - 001 - Upper Limit Exceeded
16687 - Shareware Version. To Decode all DTCs
P0303 - 008 - random misfire, cylinder 3 - Intermittent

---------

Pulled codes on the central electric system.

VAG-COM Version: Release 311.2-N

Control Module Part Number: 8E0 920 950 H
Component and/or Version: KOMBI+WEGFAHRS. RB4 D25
Software Coding: 03200
Work Shop Code: WSC 08315
Additional Info: WAUVT68E12A177909 AUZ6Z0A0318921
1 Fault Found:
01039 - Coolant Temperature Sensor (G2)
30-10 - Open or Short to B+ - Intermittent


The car is in the shop now because I don't have time to work on it this week and need it for the weekend. Groan... paying people to do work sucks.

They are swapping out the CTS at my request. They are convinced that timing has slipped. I don't buy it other wise this problem would not have built up over time to the eventual failure.

Note: It went into limp on warm start. I rarely start it warm. It has been winter and yesterday was the first warm weather warm start it's had in a while.

I'll know tomorrow if it was the CTS. I hope... fingers crossed. Otherwise I'm looking at 2 o2 sensors which makes no sense to me.

[diagnosticator]

The root cause of the symptoms will be something simple in the end, that is usually the case. Simple does not necessarily imply easy to troubleshoot however.

[Spirare]

I'm pretty certain it's the CTS. The big question I have now is how much damage did I do running it rich to the shop. I hope the cats aren't fouled. Might need new plugs too.

[Spirare]

Damn... I just reread my first post. I wrote:

16409/P0025 - Can't find this code anywhere

I never checked the generic code lists. Just Bently lists. It's a code for "timing overretarded bank 2"
Looks like I might be off a tooth... ugh.

[Spirare]

double post whoops

[downhillracer]

a bad cts can cause all kinds of weird problems

[Spirare]

Well it's not the CTS...

I'm still getting misfires like crazy. Timing is good on the sprockets and cam.

It is acting like timing is off. I'm starting to think that the VVT is messed up and specifically the exhaust timing side.

I think that the oil pressure controlled exhaust timing crapped the bed.
Anyone ever heard of this happening?

[Spirare]

Wheww... the final word is that the #3 coil pack was bad and the CTS was bad as well to throw us off the scent. It appears to be running smoothly now and throwing no codes for misfire or temp. I'm sure I'll have a CEL on soon enough and the tale is not finished yet... this is afterall an Audi.

So... thank you gents! Much appreciated.