TO407S4

Hello All,

It's been awhile since I've had the pleasure of being on these forums. Sadly life got in the way.

I've been working with AWE to address two issues with my exhaust. The first issue was corrosion on the Quad Black Diamond tips. After sending them photos they are willing to replace them.

Second, but most important issue happened while driving on the highway. Between shifts (the burp sound you normally hear) the car shot out a dirty white looking cloud out of the tailpipe (seen in my rear view mirror). Since then the sound from the exhaust hasn't been the same.

Once I got home I saw grey residue on the right tips of the exhaust. After a couple of days the residue lessened and no more debris (powder) is coming out of the exhaust.

What's been checked (Car is out of warranty 98,000km):

• Scanned the codes, and found a fault with the coolant sensor
• Brought into the dealership to check the engine and coolant levels
• Coolant sensor was found faulty and replaced
• Check Engine light came on and found that the regulating flap for the intake was malfunctioning
• Adaptation was performed on the regulating flap and corrected
• Dealership found no other issues with the car
• Double checked the codes myself when I got home and the system is clear
• No faults for O2, CATs, or emissions

Questions:

• If this was a CAT issue why hasn't the car lit up like a Christmas tree with errors? (There are sensors right on the CATs. I've monitored them in real time)
• The sound appears to be coming from a resonator. Can't the baffling have caused this issue?
• The dealership thought its an exhaust related issue... and AWE thinks it's the CATs. Have their been any CAT failures with these cars? I haven't seen any.

Image below of what I saw...
Thanks in advance everyone. Btw this car has never seen a track... but I do enjoy driving it

TO407S4

Chatting with a few friends... its starting to sound like part of the CAT is gone. Are there any bolt on high flow cats? I don't want OEM anymore... and not paying to have them installed...

TO407S4

If it's truly the CATs does the engine have to be dropped to access them?

TO407S4

Well checked the codes and it appears that I have carbon buildup. I've been asking the dealership all along if I could have tossed out ash from carbon buildup and they said if I had carbon buildup I'd know about it. Explained about hesitation and they shrugged it off. They did however provide me with the codes to look for that is covered by the extended warranty for carbon buildup on our cars. Today I got BOTH codes...

Any thoughts guys?!? Wow this forum is silent now... not how I remembered it lol

If it was the CATs I found two ways of doing it. Lowering the engine or removing... sigh.. Hope this isn't an issue to.

Codes
8931 - Secondary Air Injection System: Bank 1
P0491 00 [237] - Insufficient Flow
MIL ON - Confirmed - Tested Since Memory Clear
Freeze Frame:
Fault Status: 00000001
Fault Priority: 2
Fault Frequency: 1
Mileage: 98327 km
Date: 2014.07.16
Time: 08:02:31

8932 - Secondary Air Injection System: Bank 2
P0492 00 [237] - Insufficient Flow
MIL ON - Confirmed - Tested Since Memory Clear
Freeze Frame:
Fault Status: 00000001
Fault Priority: 2
Fault Frequency: 1
Mileage: 98327 km
Date: 2014.07.16
Time: 08:02:31

SpeedTriplemark

I would hope the Cats are covered there in Canada. In States the Cats are supposed to be warranted for 100k miles or more. 61k miles (98k Kms) seems a bit soon for carbon build-up problems (at least I hope so!). Quality gasoline and occassional bottle of Techron should help extend...

Any other hi-mileage S4 owners have this issue? I hear Direct Port Injection cars are more susceptible to carbon build-up problems (especially v8-RS4's).

TO407S4

Well hopefully with a TD1 that CATs would be covered...didn't think it was covered outside of 80,000km I've read on here before that people have had carbon build-up issues with these cars. Actually with less mileage than my car. Just pondering if it would have tossed out ash.

Car only sees Ultra 94. On a side note I was told even with a TD1 the cleaning of the carbon build-up would be covered. (As per the note sent out by Audi Canada)

Audi Canada Warranty -- From their website
New Vehicle Limited Warranty

The philosophy behind our Audi protection program is quite simple. You drive the car, we back it for 4 years or 80,000 km. Only those who build cars this well would dare to protect them this comprehensively, and offer such extensive service packages.

As an owner of a new vehicle, you will receive:

• The first scheduled maintenance service at 8,000 km or 12 months, whichever comes first, free of charge.
• 4 years or 80,000 km, which ever comes first, new vehicle limited warranty.
• 12-year limited warranty against corrosion perforation.
• Audi 24-hour Roadside Assistance for 4 years.

TO407S4

Had a chat with the dealership. Car goes in tomorrow for a scan and sent to Audi Canada for approval. They said it'll be approved due to the nature of the fault. (engine design)

The CATs they believe are fine and are covered for 7yrs. He said to wait for codes...

TO407S4

Picked up the car. Exhaust note is still the same. They cleaned the carbon build up, and the cars hesitation appears to be gone. They are emailing me the statement of work. I'll post details on what was done if anyone is interested.

I have to say after complaining at the dealership and explaining that I received the extended warranty for carbon build up, they just did the work without the TD1 run around

TO407S4

Quick update:

The car is still shooting out grey debris and I contacted the dealership letting them know that I still think there is an issue with the CAT. They assured me it wasn't.
Today my check engine light came on and when I scan the logs, it clearly points to the CATs.

This dealership "was" mod friendly and pushed mods back when I went to buy the car. This is because they have their own tuning division. Since the CATs are covered for 7yrs I really hope I don't get the run around.

Well I'm two for two... carbon buildup and CAT..
1 Fault Found:
6093 - Catalyst System; Bank 1
P0420 00 [237] - Efficiency Below Threshold
MIL ON - Confirmed - Tested Since Memory Clear
Freeze Frame:
Fault Status: 00000001
Fault Priority: 2
Fault Frequency: 1
Mileage: 98542 km
Date: 2014.07.20
Time: 11:22:27

TO407S4

Any suggestions...please let me know