I guess the title tells the end of the story but there is a SURPRISE that really has me puzzled...

Backstory: "BIG SEXY" my 2008 C6 Avant is getting long in the tooth. 172,186 to be exact and is really starting to have issues. I had a CEL come on in December and from previous diagnosis thought it was time for new plugs. Got new plugs, went to install them and noticed a decent amount of oil in the spark plug wells. Buttoned it all back up and took it to a good local indy shop. Valve cover gaskets were relatively new (we've been chasing oil leaks for a bit, it's an Audi) so we figured it wasn't those. Long story slightly shorter, ended up doing cam seals/gaskets, actually did redo valve cover gaskets, brake vacuum pump gasket, spark plug tube seals, camshaft adjuster solenoid, serpentine belt tensioners and belts, idler pulley...a lot of stuff. All was good for about a week and then...oil puddle.

Took it back and diagnosis is oil filter housing and possible oil cooler gasket leak. Another $1700 but I didn't do any of that because I was frustrated and needed to think. I think I can handle the Oil cooler gasket, maybe not the housing...still thinking.

Monday of this week...CEL. Don't have a VAG COM so took it to AutoZone and codes showed cylinder misfires on 3 and 1 (which going over service records over the past few years is there have been misfires on 3 and 1 on multiple occasions) and Vacuum Pump -V22, Activation Ground (GND) - Upper Limit exceeded. Car was running fine so just keep driving it but yesterday, the BRAKE PAD WARNING LIGHT comes on. WTF?!? I look at the front pads and there seems to be PLENTY (haven't take the wheel off and put calipers the pads to see EXACTLY how much) of meat left on them. I am going to take the front wheels off and check the wires to see if they are ok but...would LOVE to hear some folks ideas on what might be going on with my car.

Thanks for reading...

 

Get CARISTA or VAGCOM, otherwise your doing little more that throwing darts at a dart board in that car. It seems to me that you have had a major catch-up session on the cars routine oil leaks. So, if you are keeping the car, you are caught up.

Not certain which Brake light comes up - there is a difference between pad wear and the E-brake. The E-brake freaks out on mine if the battery is at the low range.

As to the misfires, if they were not present prior to the work then the first place I would look is at the wiring for the fuel injectors and an associated ground back behind the oil filter housing. Sort of a shot in the dark, but it had to be disrupted to remove the housing.

 

Thanks for your response.

I have had a major $5K catch up session on the oil leaks but still have some work to do. The oil filter housing leaks don't look fresh so I think the puddle came from the oil cooler, also because of where the puddle was located in relation to how/where the car was parked. It happened when we were below zero here and since it has warmed up I am not seeing any puddles. I may wait until I am due for an oil change or I see more puddles before I do the cooler gasket. Unfortunately I am kinda FORCED to keep this car for a bit, which I'm GOOD with if I can get all these things, PLUS all of the suspension work that needs to be done...sorted.

It was a circle with BRAKE PADS! underneath it. I have NEVER seen this warning before on either of the cars I've owned so that was a NEW ONE. I kinda felt like it might be something electrical. The warning did not appear the two times I drove the car today.

As I look at all my service records I see those same misfires going back a few CELs. There was just a bunch of work done in that area doing the cam-related seals/etc. as well as poking around the oil filter housing so...wiring could have gotten trampled. Should the wiring for the fuel injectors/ground be easy to locate?

 

I would always resist the temptation to just go in a fix things on these cars. Your misfire likely show up with a fairly precise cause in VCDS or another tool.

 

Misfires can happen with and without any other indications. Carbon buildup is one of the biggest culprits, along with PCV issues.
But, I do strongly suggest getting VCDS, as it can help you in many many ways.

 

I have a 2008 A6 4.2 with 175k miles. I was chasing misfires for awhile around 170k miles. Turned out to be the fuel injectors. I did a carbon clean and fuel injector clean. Onr injector was in pretty bad shape so I replaced it. Runs smooth as butter now.

 

I have had the carbon cleaning done approximately 12,000 miles ago, how long does a carbon cleaning last? I am wondering if injectors might be the cause of my misfires.

 

GOT ONE! Thanks for the mention of the CARISTA, I hadn't even heard of that one and wasn't sure I wanted to plunk down all that cash for a VAG COM. I ran the diagnostics and here is what it came back with. Would GREATLY appreciate your input on the findings of the CARISTA. The misfires are dated back in December which is when I had all of the seals/gaskets/coils/plugs done. Not sure if the codes just weren't cleared but, those same misfires go back a while so wondering if injectors may be a problem in those cylinders (?). I had a Carbon Cleaning done ~12,000 miles ago.

I am grasping at straws because, I don't know what I'm doing really ☺️.Basic OBD2:
P0303 (Confirmed) - Cylinder 3 Misfire Detected



Engine:

P0300 - Random/Multiple Cylinder: Misfire Detected

P0301 - Cyl.1: Misfire Detected

P0303 - Cyl.3: Misfire Detected

P0456 - EVAP Emission Contr. Sys. (very small Leak): Leak Detected

P2070 - Intake Manifold Tuning (IMT) Valve Stuck Open



Transmission:

P1890 - Signal wire for Tiptronic: electrical error



ABS:

00473 - Electronic Parking Brake Control Module -J540-: Please read DTC



Parking brake:

02443 - Operating unit: Electrical error in circuit



Infotainment display:

01964 - Memory Seat Control Module / steering column adjustment: No signal/communication



Digital radio:

02635 - Tuner not enabled/activated

00446 - Function limitation due to insufficient voltage: Lower limit not reached



Sound system:

02558 - Left rear mid-bass speaker: Open circuit



Heater & air conditioning:

01087 - Basic setting not performed: no or incorrect basic setting/adaptation

00256 - Sensor for refrigerant pressure/temperature: No signal/communication



Body/convenience system:

01134 - Alarm horn: Electrical error in circuit



Driver's door:

02115 - Lock unit for central locking: Implausible signal



Front passenger's door:

02115 - Lock unit for central locking: Implausible signal

02116 - Mirror adjustment motor: Short circuit to ground



Trunk:

00317 - Rear lid control module: Implausible signal



Battery regulator:

02272 - Static current stage 1

02273 - Static current stage 2

02274 - Static current stage 3

02276 - Static current stage 5

02277 - Static current stage 6

 

Injector Service along with a new fuel filter is likely due but you could first try an injection cleaner fuel additive to see if it helps with the misfires.

 

Thanks for your response. That fuel additive seems like an easy first place to start, will order a bottle.