Had starting issues totally randomly for months now, works half the time, even the occasional mid drive shut off, sometimes wont restart for hours, sometimes right away. Was almost totally fine all winter, now more and more, possibly heat related. Codes are....

00787 - Temperature Sensor in Fresh Air intake duct (G89)
30-00 - Open or Short to Plus
00603 - Shareware Version. Foot-wall/defroster Flap Motor -V85
41-10 - Please Register/Activate - Intermittent
01272 - Shareware Version. Central Air Flap Motor -V70
41-10 - Please Register/Activate - Intermittent
01274 - Air Flow Flap Positioning Motor (V71)
41-10 - Blocked or No Voltage - Intermittent
01206 - Shareware Version. Signal for Duration of Ignition Off Time
27-10 - Please Register/Activate - Intermittent

I've heard the CPS is a very common fix for these problems, one is in the mail. Certainly appears electrical, but no idea how to verify the fuses/relays/bad grounds, any help or similar issues would be great!

thanks all

 

quick 5 minute drive, now the codes are...

16795 - Secondary Air Injection System: Incorrect Flow Detected
P0411 - 35-00 - -
17925 - Shareware Version. To Decode all DTCs
P1517 - 35-10 - Please Register/Activate - Intermittent
16684 - Shareware Version. To Decode all DTCs
P0300 - 35-10 - Please Register/Activate - Intermittent
16686 - Cylinder 2: Misfire Detected
P0302 - 35-10 - - - Intermittent
18014 - Shareware Version. To Decode all DTCs
P1606 - 35-00 - Please Register/Activate
16688 - Shareware Version. To Decode all DTCs
P0304 - 35-10 - Please Register/Activate - Intermittent

Didn't clear anything, just now getting these somehow

 

final update today, cleared the codes, only thing left was the ABS module, which has been toast for a while, not a big deal (unless the wiring in this is causing my issues somehow), drove it around and let it idle for a while hoping it would cut off or have trouble starting, or course its perfect when I'm trying to re create it. Will post codes of what comes back when it breaks again

 

Well for starters, lets clean it up a bit:

16795/P0411: Secondary Air Injection System: Incorrect Flow Detected
17925/P1517: Power Supply Relay for ECU (J271 or J363): Electrical Malfunction
16684/P0300: Random/Multiple Cylinder Misfire Detected
16686/P0302: Cylinder 2 Misfire Detected
18014/P1606: Rough Road/Engine Torque Signal from ABS: Electrical Malfunction
16688/P0304: Cylinder 4 Misfire Detected

Now, can we have some more info on the car. 1.8 or 2.8 will help with the misfire diagnosis.

 

sorry, thought my tag had it.

2000 A4 1.8t ATW quattro

 

admittedly my knowledge of 1.8's is slim regarding misfires, but it seems you may not be worried about that anymore? Though it may come back so check oil on the plugs, old plugs in general, coil packs, etc.

the secondary air could be a few things in that system so check that the pump comes on when the engine is cold (morning). also check that the hoses around that pump there don't have any cracks/leaks

I've never seen the power supply relay one but it looks like it may just be a bad relay.

and the abs may just mean you need a new abs or wiring on the brakes might be shot so check down there next time you have the wheels off.

these are all my best guesses, I am nowhere near an expert like a lot of guys here. also since you reset everything and only one came back you may have just got come odd fluke codes (though that's rarely the case). good luck!

 

thanks eldurino, i checked all the hoses I could find, no leaks as far as I can see.

Went to check the relays, the ECU power relay is there, not sure if its ok, but either way I have a new one on the way. I've never looked at my relays before, but it doesn't look like any other pics I've seen, there is some huge mission impossible hacking device in there. pics below. Not sure what exactly this is, but it looks aftermarket, nothing I ever installed.

Hopefully by tom I'll have the ecu relay and CPS and get deeper in to install and figure out what this is. thanks

 

woah, no idea what that is. it almost looks like a ballast for a headlight, but I don't know why that would be down by your relays

 

ok so it is some sort of a Tsunami amp, speaker wire set up, nothing I put in there. It connects just below 372, and then goes toward the front of the car somewhere I can't see.

As I am chasing what might be an electrical issue, I want as little variables as possible, but I may introduce more by yanking it, or it might be the cause of the intermittent issues.

Ultimately still waiting on the ECU relay, and CPS to arrive, as well as the car to cut off or not start again so I can re read the codes.

 

some sort of old connection for amps and subs. had trouble tracing it further than the relay box because of stuff in the way, but checked out the trunk, never opened the floor past the spare tire until now. Certainly used to be amps/subs in there. 5 exposed wires. One goes to the speakers on the passenger side through the trunk wall. The big one on the left is just cut and glued down, middle red same, right brown one is attached to the metal there? Then one small blue one loose as well.

None of this matters to me right now at all, speakers work just fine, I'm just worried all this unfinished craziness could be related to my possible electrical starting/cutting issues