New POS or new ECU
 

Hello, I am trying to determine what is most likely the problem and I would like the group opinion if you have a minute.
I have a 1999 a4 1.8t mt avant with a constant misfire on Cyl #3. I have a ross-tech vag system and have checked thoroughly all related systems and here is what I have.

Codes -18010,17645-8,16684,16687,18014

The work I have done is as follows. Replaced coil #3 and No spark on coil#3.
Using my noid light and the factory wiring diagram, I found that wire terminal 1 of each coil connector was receiving a signal except for coil #3. So I checked at the power output stage for signal and same result-no signal on #3. I then checked both incoming signals and outgoing signals at the power output stage and found that again #3(confirmed through testing each wire and verifying where it went with meter and wiring diagram) was getting no signal. I then tested continuity on all four wires from ecu to power output stage as well as Power output stage to coil pack harness connections. ALL GOOD CONTINUITY! So, stumped, unfortunately It seems to me that all it could be is the ECU as that is the source of the coil signal??? I was told to replace the Power Output Stage(POS) but if there is no signal coming TO the POS from the ECU, then of course there would not be a signal passing through the POS for cylinder #3 unless there is some sort of back feed signal from the POS to the ECU that I am unaware of. I am hesitant to spend the money for an ecu as I have falsely gone down that road on another vw golf. thanks for any input-
By the way, I know codes 17645-8 all came up from me disconnecting the injectors one by one, so really 16687 and 16684 are consistent with my problems.

Thanks again,
John-

Why are you starting a new thread for this?

https://www.audiworld.com/forums/sho...php?p=24514590

I think you should delete this thread and go back to the original. Spamming is certainly not the way to fix the issue.

Are these codes new? In other words, have you cleared the codes to see what come back? Did you look up the codes? If so, please post the meanings. There are very few people who have memorized even a few codes. It's not very considerate or efficient to have everyone who reads your thread look up 8 codes individually.

My original advice stands. Stop poking around with your meter before you damage something.

How is he spamming if he is asking Audi questions and trying to work through problems in a Audi forum? Should he ask in the GMC or BMW forum?

He already has an open thread that is being worked. When I posted, it was one or two posts down from the top. There was/is no reason to start another thread. All that does is scatter the information so that anyone trying to help has to read both threads to get the full picture.

I get that the problem may be frustrating, but spam (yes, I stick with my characterization of this thread as spam) is not the way to find a solution.

Well, i tried to simplify the details and eliminate unnecessary sections as there is quite a bit of info there. So, thanks for being really aggressive on your response and also not following up on your 3 word "advice." I simply asked why you thought it was the POS and no response(both privately and in the thread.) My poking around is a lot more based in knowledge than you know, but thanks for trying to treat me like a little boy. This dialog is not helping anyone, so if you would like to continue, please contact in a private message. By the way, look up "spamming". If I resolve this myself, I will definitely post what I found because I would like this to be helpful troubleshooting, not just throwing parts based on ???

codes details:
18010 Power Supply B+ Terminal 30: Voltage too Low - battery near dead
18014 Rough Road/Engine Torque Signal from ABS: Electrical Malfunction - ABS problems for a while
16684 Random/Multiple Cylinder Misfire Detected - why the post on the forum
16687 Cylinder 3 Misfire Detected - current problem-why the post on the forum
17645-8 Fuel Injector for Cylinder 1 (N30): Open Circuit - from diagnostic procedures, cleared w/ no return

sorry, yes codes cleared and 16684,16687 returned immediately.

Good idea, but why not post it in the original thread for full context?
Sorry for the lack of follow up. There are other things I do during the day other than respond to posts on this forum. Given my experience, that is the most likely culprit and certainly something you want to eliminate. That is your interpretation. I simply stated that multiple posts do not help anyone. Perhaps you are overly sensitive?
Multiple posts on the same topic are generally referred to as "spam" on this forum and many others. It's a derivative of the original email spam.
With a POS, it's generally a question of "when" rather than "if". Like a coil pack, it's not a bad idea to have a spare on hand. Since it is cheap, widely available, and prone to failure, why not just replace it and reset the codes?
This is important information. Looks like you need to have your ABS control unit rebuilt too.

I know a few meanings of POS but what does it mean when it is being used as a Audi part?

Power Output Stage. More commonly referred to by non-VAG people as an ignition module.