Multiple issues (starting, limp mode and no cruise control)

[wriscolf]

Hey guys, I have a 2007 A4 S-Line Titanium edition. I bought it a month ago and since day one of owning it I've been having issues. Coming from a Nissans to this I am confused and starting to regret transitioning to Audi. I love the car but one month in and problems starting to pile it feels.

I'll start off from the beginning. So the first issue was that the car would go into Limp Mode when it was on a tune. I told the guu to get it reflashed since that same issue happened to my older brother when he owned a B6. Guy reflashed it. I went on a test drive everything was good. Paid the guy. He went on his merry way. I get my plates but was missing one screw so I went to advanced auto to get the plate screws. Put it completely on drove home which is maybe a 5 minute drive locally not far. Turned left on intersection boost did kick on and boom limp mode. I come to a red light then stalled at light and the car was having difficulty starting. I got it to start on rather quickly and limp mode was done. I drove him parked in drive way. Turned it off and turned it back on and it wouldn't crank over. I called the ex owner and he told me that's what was happening to him before the reflash. He said to take it off the tune. I did. Car didn't start. He told me he'll come over in the morning to figure it out. He comes over and car didn't start and I got multiple codes (as follows P0444, *P0243, P2294). I searched here checked fuses, changed purge valve but still having same issue so we started to Check resistance on it. The original one was closer to what I searched on forums at 14 (someone on here said it should be at 16 or something. This was a month ago I can't remember the number) and the brand new audi part, from dealership, was at 13. So we left the old one and ex owner kept the "new" one to take back to audi. Since the codes seem to be electronical we checked for short cables. We worked all day and found everything to be as it should. No chewed cables everything seems to be plugged. It was getting late and we just called it the day and we put everything back together and car started up.

Car worked fine for about 2 weeks ago, I actually drove it a lot, an hour away from home and back. To work and back. Then the start issue returned but it would start after a few "take out key from ignition and try again" with occasional "use fob to lock and unlock car then try again". My brother and I have been on debate on battery and alternator. Yesterday we changed the battery and car didn't want to start at all. We thought it was Apr tune so we start trying to mess with cruise control to change tunes, or unlock security code but had no luck getting a response from the tune. No flashing of check engine light or other light. We checked on here again and everyone said key fob reset. So we reprogrammed it and boom we got it to start. I drove it around to find a auto zone or pep boys to check alternator. Failed horribly since they either was backed up and understaffed. I checked 3 stores before my body was asking for dinner and bed. My brother said car should start fine in the morning so I can go to work. So I went home. No issues with car. Mind you car started fine after 3 different turn off and turn on at the autozones.

I wake up this morning to start the car and nothing. I pulled the key out of the ignition, disappointed and hopeless about it the situation then put key in and boom, car started.

I haven't changed the alternator yet and will be going to auto zone after work to get it checked. I am not sure if this issue is common or specific or if I have many little big problems giving me a big problem. After a lot of convincing of my brother to reach out here, I caved in and here's my issue. Anyone can help me out?

Just something that just hit me, the car seems to pull. More after battery change. I don't have a boost Guage but the app torque raid peak boost at 21,16 and holds around 10.

Mods are as follows: MagnaFlow cat back exhausted and APR tune stage 1.

Thank you so much for any input. Also please ask away. Maybe I tried it or not tried it.

[wriscolf]

Sorry about the how this tread looks. I'm on mobile and it's quite hard to do this in the middle of work.

[wriscolf]

So in summary since I realized I typed a lot:
Issues:
1) When in Apr tune mode 3 (93 octane) car goes into limp mode.
2) Start up issue
3) No longer can change tune or access APR options via cruise control stick

[Silveravant]

Do you ever get an EPC light?

[KingWulfgar]

So in summary since I realized I typed a lot:
Issues:
1) When in Apr tune mode 3 (93 octane) car goes into limp mode.
2) Start up issue
3) No longer can change tune or access APR options via cruise control stick

If you have multiple programs and disconnected the battery, you are set back to whatever program was loaded as the first one. Usually stock, but I'm not sure that's guaranteed. This is one thing they warned me about at APR--a lot of people think it lost the tune, but it's just that it defaulted back to program 1.

[wriscolf]

Do you ever get an EPC light?

Yes it came on when it went to limp mode. But it hasn't returned. I don't even see it flashing when I try to set a tune.

[wriscolf]

If you have multiple programs and disconnected the battery, you are set back to whatever program was loaded as the first one. Usually stock, but I'm not sure that's guaranteed. This is one thing they warned me about at APR--a lot of people think it lost the tune, but it's just that it defaulted back to program 1.

It feels faster then when I manually set it to "stock mode". I can't change it. I get no flashing of CEL or the other light. Think it's locked?

[KingWulfgar]

It feels faster then when I manually set it to "stock mode". I can't change it. I get no flashing of CEL or the other light. Think it's locked?

It's either locked with a security code or you don't have multiple programs. I didn't bother with the security lockout feature, but the manual reads like the lights won't flash indicating EMCS mode until after you input the correct code using up/down on the stalk.

[Silveravant]

With those codes, limp mode and EPC light I would check the 614 relays under the ECU. My relays looked/tested fine, but when I replaced them the problem went away and has not returned.

[Okedokey]

Also check the battery voltage, inspect for water under ECU plenum.

[wriscolf]

It's either locked with a security code or you don't have multiple programs. I didn't bother with the security lockout feature, but the manual reads like the lights won't flash indicating EMCS mode until after you input the correct code using up/down on the stalk.

OK I'll try to do this when I get a chance. That's exactly what I thought but the ex owner gave me the pdf file. And on there it said it should blink so I was waiting then gave up on it. I'll do it again. Thank you so much.

[wriscolf]

With those codes, limp mode and EPC light I would check the 614 relays under the ECU. My relays looked/tested fine, but when I replaced them the problem went away and has not returned.

We did check it and it looked fine. I should have gotten it. It's such a pain to get to those relays. Thank you so much. I'll give it a shot soon once I'm able to get to the tune.

[wriscolf]

Also check the battery voltage, inspect for water under ECU plenum.

Brand new battery and the alternator is reading at 12.95v. I'm changing it this weekend.

[Okedokey]

Brand new battery and the alternator is reading at 12.95v. I'm changing it this weekend.

There is your issue.

[wriscolf]

There is your issue.

That can fix all my issues? Or just the start up? I didn't know these cars are that finicky. Thank you again. I'll update after alternator is in.

[Okedokey]

If the electronics isn't getting the required voltage due to voltage droop etc, yes, it will throw all kinds of weird codes.

[wriscolf]

Update: brand new battery and alternator. Went to Autozone to get both checked, battery is fine and new alternator seems to be reading lower than my previous one. What i'm going to do is get a multimeter and checked myself. I'm not sure if it's their machine or the car. I'm getting more confused with this car. Next is the relay under the ECU as suggested on here. There's two. I am just going change both. Just got to find where to get it.

[wriscolf]

I forgot to mention I am not getting any codes anymore. I only got codes a month ago. After the change of battery and alternator, the same day the car was having issues to start like it would crank but not start. It took some playing with remote unlocking and locking and key removal of ignition to start. The next morning the car had some issues as I had before, which is cranking but doesn't start until I removed the key out ignition and tried again and it started. Still no cruise control when I turn it on. Also unable to get to my tunes.

[wriscolf]

If the electronics isn't getting the required voltage due to voltage droop etc, yes, it will throw all kinds of weird codes.

Brand new battery and alternator. Didnt solve issue.


I think its the relay so im going to change that today. Hopefully the wiper removal tool comes in from amazon today. I am already over this car. My excitement for it died not even a month or so in.

[Okedokey]

Well your car was under powered so they needed sorting regardless. You need a VAGCOM. Did you get a new voltage regulator with the new alternator or transplant the old one?

Also, have you checked for water under the plenum yet?

[Sanjman]

Just because you got another alternator doesn't mean you got a good alternator. I've had my bad alternators from autozone on my other car several times before I received a "good" refurbished one.

[wriscolf]

Well your car was under powered so they needed sorting regardless. You need a VAGCOM. Did you get a new voltage regulator with the new alternator or transplant the old one?

Also, have you checked for water under the plenum yet?

I did check under ECU when i changed the 614 relays. I put new 644 ones. It was dry. No signs of water ever being in there. I changed the Alternator completely. From how you stated your question i am assuming the Voltage regulator is a complete different other part. Where is that located?

After i changed relays it cranked right over but it seems it was because car was somewhat warmed up. This morning before work i cranked it. She started at first try but it wasnt as smooth as she usually is when car is warmed up.

[wriscolf]

Just because you got another alternator doesn't mean you got a good alternator. I've had my bad alternators from autozone on my other car several times before I received a "good" refurbished one.

Thats what im thinking now after the start up today. I have to go to my brothers house and get my multimeter and read out the outputs. I dont mind it being the alternator since it has lifetime waranty and its a easy job to do.

[wriscolf]

Just because you got another alternator doesn't mean you got a good alternator. I've had my bad alternators from autozone on my other car several times before I received a "good" refurbished one.

So I checked the voltage on battery it was 12.7. I turned on the car and checked the voltage and it didnt go up much. i think it hovered right under 13. I checked the alternator itself and its at 14v! I dont understand. I am guessing a bad ground. So i checked for ground and i am having resistance. So i am assuming that theres a bad ground somewhere. Do you know any of the ground points for these cars from factory. I did read up on the big 3. I am thinking of doing this now but considering how hot this car gets im scared of melting of insulator and such. Maybe i can fix the stock points?

[Sanjman]

How much resistance? Do an ohm check between the battery negative and all other grounds... I think the engine itself is grounded. Or any metal chassis that's bare metal.

Sent from my SAMSUNG-SM-G925A using Tapatalk

[wriscolf]

How much resistance? Do an ohm check between the battery negative and all other grounds... I think the engine itself is grounded. Or any metal chassis that's bare metal.

Sent from my SAMSUNG-SM-G925A using Tapatalk

I am getting a negative four resistance. (-4).... I never knew a negative resistance existed. That's coming from touching the rear cover and on top of the alternator. I checked the alternator voltage directly by having negative on battery and positive on positive terminal on battery. It reads at 13.9v with a load on (ac, lights and radio). Checked from the battery terminals it's at 12.9v. Something is definitely not right. Something stopping the alternator to fully charge the battery.

[wriscolf]

The resistance test was with negative pole on battery negative and the positive on the location above. Sorry. I wasn't clear on first post.

[wriscolf]

BUMP

Need some help from professionals, Not sure if its a bad ground or voltage regulator on the alternator. Dont want to make a move until I get a good idea. I only get to work on car on weekends.

[wriscolf]

Update with some solutions thus far (well it seems like) for those looking for answers for any issues. *knock on wood*

So in summary since I realized I typed a lot:
Issues:
1) When in Apr tune mode 3 (93 octane) car goes into limp mode. (Changed two relays under ECU and ive been driving with my tune and have done big pulls without it going into limp mode. *knock on wood*
2) Start up issue I changed battery and alternator seems to fix the problem but the new alternator is not charging right so im changing this and hoping this is fully resolved.
3) No longer can change tune or access APR options via cruise control stick The tunes were locked by security feature. I managed to get it responding after doing the above changes and put the security code in and i have all my modes in APR tune.

The no cruise control issue was a bad Clutch Sensor under the dash. Oh the luxury of cruise control!