Six different codes..need help plz

[Tacosalad]

Well yesterday I woke up and my headlights didn't work. After some searching of the forums and speaking with a couple different people I resolved the problem by replacing my headlight switches. But once I put all the wiring back on, plugged my airbag back in, started the car and boom. Check engine light popped on. The car idles totally fine, the only problem while running is when I come to a stop, or begin to stop. The RPMs drop to like ~500 and unless I give it some gas, the car will otherwise die. Not even a month ago I had a code coming up as TB failure. But I reset the TB and cleaned it out which resolved the problem and the car ran fine. During that time, when the TB wasn't fixed, the car would idle extremely low in RPMs and die when I come to a stop as it does now. Also I noticed that there was a clamped on the hose connection to my TB that wasn't tightened, it was so loose I could turn it with my hand. When I looked into the TB this time, there was a lot of gasoline on the valve and on the gasket. Could all this be connected in some way? Maybe not, I'm not sure. I also cleaned out my MAF Sensor and replaced my air filter along with my fuel filter today. Cleaned out my air box as well. But I got the codes pulled and I got this:


P0134
Definition: Heated oxygen sensor - bank 1 sensor 1 (H0sS11) sensor circuit no activity detected
Explanation: Air/Fuel ratio concern- lean or rich
Probable cause:
- Open or short circuit concern.
- Faulty H02S11 (Bank 1 Sensor 1)

************************************************** ******************************-

P1198
Definition: 02S heater circuit bank 1 sensor 2 electrical malfunction.
Explanation: Open or short circuit condition
Probable cause:
- Poor electrical connection
- Failed H02S (Heated oxygen sensor)

************************************************** ******************************-

P1196
Definition: H02D21 Slow response (Heated oxygen sensor - Bank 2 Sensor 1)
Explanation: Oxygen Sensor has a slow reponse during testing period.
Probably cause:
- Defective oxygen sensor
- Very lean air fuel ratio
- Very rich air fuel ratio

************************************************** ******************************-

P0102
Definition: Mass or volume Air flow sensor circuit low input.
Explanation: Air duct tube damaged
Probable cause:
- Large vacuum leak on engine
- Faulty MASS sensor

************************************************** ******************************-

P1472
Definition: EVAP control system LDP circuit short to ground.
Explanation: Open or short circuit condition
Probable cause:
- Failed Leak Detection Pump (LDP)

************************************************** ******************************-

P1425
Definition: Tank Ventilation valve short to ground.
Explanation: Open or short circuit condition.
Probable cause:
- Failed EVAP canister purge regulator valve


I'm really trying to avoid taking it to the auto shop, really my last resort, money is really tight at the moment. So I'm really hoping I can get some input on these problems while I continue to research and browse forums.
My knowledge of cars is pretty limited, everything I know is mostly from these forums and doing a lot of searching so I'm trying to find a sense of direction as to where all these problems might be coming from. Could all these electrical problems be related to me pulling my airbag off and all those electrical connectors?

Thank you to anyone who doesn't go TLDR lol...Really appreciate any help guys, thanks a lot.

[blacka4]

Lets take this step by step

P0134
Definition: Heated oxygen sensor - bank 1 sensor 1 (H0sS11) sensor circuit no activity detected
Explanation: Air/Fuel ratio concern- lean or rich
Probable cause:
- Open or short circuit concern.
- Faulty H02S11 (Bank 1 Sensor 1)

This could be caused by a O2 sensor being unplugged or bad.

A code P0134 may mean that one or more of the following has happened:

•Bad O2 (oxygen) sensor
•Bad heater circuit in the O2 sensor
•Wiring or connector to the sensor frayed / broken
•Blown heater circuit fuse
•Holes in the exhaust system
•PCM failure

P1198
Definition: 02S heater circuit bank 1 sensor 2 electrical malfunction.
Explanation: Open or short circuit condition
Probable cause:
- Poor electrical connection
- Failed H02S (Heated oxygen sensor)

This could be caused by the same O2 Sensor that failed above

P1196
Definition: H02D21 Slow response (Heated oxygen sensor - Bank 2 Sensor 1)
Explanation: Oxygen Sensor has a slow reponse during testing period.
Probably cause:
- Defective oxygen sensor
- Very lean air fuel ratio
- Very rich air fuel ratio

Save thing here O2 Sensor not getting the required power to read the exhaust

P0102
Definition: Mass or volume Air flow sensor circuit low input.
Explanation: Air duct tube damaged
Probable cause:
- Large vacuum leak on engine
- Faulty MASS sensor

You said you cleaned the MAF...make sure you plugged it back in and that you didn't mess anything up inside the MAF...if you did break something you are going to have to replace it

P1472
Definition: EVAP control system LDP circuit short to ground.
Explanation: Open or short circuit condition
Probable cause:
- Failed Leak Detection Pump (LDP)

EVAP canster pump has a leak...common problem in this system

P1425
Definition: Tank Ventilation valve short to ground.
Explanation: Open or short circuit condition.
Probable cause:
- Failed EVAP canister purge regulator valve

EVAP system failure..



I hope this helps.. looks like you might have to replace your O2 sensors..also you could have a vaccum leak forming causing the EVAP codes.

[Tacosalad]

Wow thanks for the quick response. I'm not really familiar with the EVAP system, but could that be a result of that clamp being very loose on the hose connecting to TB and intercooler? Also speaking with someone who helped me with my TB problem earlier, he thought there might be a problem with my CATs. Does that sound plausible?

[blacka4]

yup the O2 Sensors are before and after the CATs. the Evap problem is a vaccum leak or something Ijust remembered a loose fuel cap

[Tacosalad]

Okay thanks a lot. Sounds like I'll have to bring it to a shop. I don't know much about CATs

[blacka4]

Okay thanks a lot. Sounds like I'll have to bring it to a shop. I don't know much about CATs

Not too much to know, other then when they go bad you replace them...and one way to tell they are going bad is if the car runs like poop and spells like rotten eggs

[Tacosalad]

Well it smells fine lol. The only problem I can think of is that the car dies when I come to a stop.

[Tacosalad]

Also how do I deal with a vacuum leak thats forming my EVAP system problems?

[Tacosalad]

Replacing my MAF sensor and my O2 sensor soon. Not quite sure what to do about the evap leak though.

[blacka4]

one way to find the vaccum leak is take a smoke machine and push smoke through the vaccum lines with the car not running to see if you can find where it is leaking. the car dying when you come to a stop could be caused by the engine choking because the exhaust is plugged (ie cat is plugged)

I'm going to assume this is a 2.8

[Tacosalad]

No its a 1.8T quattro. Okay I'll start by doing that to find the leak. Really hope I don't have to replace a cat. Is there a way to find if the cat is plugged up without taking it off?

[Poopie]

check your fuses. specifically the engine timing fuse.

[walky_talky20]

check your fuses. specifically the engine timing fuse.

BINGO. If your car is a 97, 98, or 99, check fuse #29. If your car is a 2000 or 2001, check fuse #34. I'll bet it is blown. All of your codes point to that. Don't replace any parts until you have checked this. Sorry I didn't comment earlier, I must have missed this thread.

As a side note, it is always important to give the model year of your car, and engine code (if you know it) when asking for technical and diagnostic helps. It matters a lot.

[Tacosalad]

Okay thanks a lot ill do that. Ty for all the responses.

[Tacosalad]

Well I located fuse #29 in my fuse box and there isn't even a fuse there :P

[Tacosalad]

1997 a4 1.8t aeb btw

[blacka4]

BINGO. If your car is a 97, 98, or 99, check fuse #29. If your car is a 2000 or 2001, check fuse #34. I'll bet it is blown. All of your codes point to that. Don't replace any parts until you have checked this. Sorry I didn't comment earlier, I must have missed this thread.

As a side note, it is always important to give the model year of your car, and engine code (if you know it) when asking for technical and diagnostic helps. It matters a lot.

i didn't know this...thanks walky...

for shits and giggles check fuse 34...engine timing fuse?? wouldn't that be the same as ignition?

[walky_talky20]

There should be a 20A fuse in slot #29. Check for metal contacts in that fuse location with a flashlight. If there are contacts there, put a fuse in it. I am quite sure you should have one there. I just double checked with a Bentley manual. In the fuse box, it is in the far left vertical column of larger fuses, second from the bottom.

That fuse powers ONLY the following:
- O2 B1S1 heater
- O2 B1S2 heater
- Mass Air Flow Sensor
- EVAP purge valve
- Leak detection pump
- N75

Fuse #34 powers only the fuel injectors. This information is for 97-99 1.8T only. It all changed for 2000 model year.

[Tacosalad]

Wow that's exactly the problem haha. It was a 15A fuse though according to my manual. But thanks a lot, really. You just saved me like $400 lol. Thank you so much.

[brockallentaylo]

Wow that's exactly the problem haha. It was a 15A fuse though according to my manual. But thanks a lot, really. You just saved me like $400 lol. Thank you so much.

Insert applause for walky_talky ! This is the way to think when groups of things fail together. Try to find a common ground they are sharing or common power supply (fuse). If you had a multimeter you can check each items power supply 5-12v depending and connect the dots from there. I think the pre face lift cars share their igniter fuse with 2 or 3 other sensors as well. Glad your up and running!

[blacka4]

wow, I stand corrected..good job. If we still had the rep system I would def. pass some out here. I never would have thought a fuse. I guess I assumed they where all there.

[walky_talky20]

Yes, this why I always consult an electrical wiring diagram, even for quick questions on AZ, lol. Without it you are flying blind. I refuse to work on electrical problems without one. Once you start assuming things, you can often get on the wrong track.

OP: I'll bet your car is *way* faster now. With that fuse removed you would have had almost zero boost pressure. 1.8 Non-turbo style. Glad I was able to help. Your bill is in the mail...I kid, I kid.

For posterity: The key term that helped me to diagnose this issue quickly (and over the internets) was the last 2 codes which read "short to ground". In Audi language, short to ground almost always refers to a blown fuse. Not always, but almost always. Also, the MAF won't throw a short to ground or open circuit code when it loses power, just a "low input" code.