EPC and Check Engine light

[dabarjel]

Please help, my 2015 Audi a3 1.8t has gone into a limp mode and has an EPC and check engine light on. I can mash the gas and it will SLOWLY accelerate. Also idles pretty rough and struggles to shift out of 2nd. My loud intake turbo noises are gone, my speed is gone, my soul is gone plz help!

[Grey3]

Please help, my 2015 Audi a3 1.8t has gone into a limp mode and has an EPC and check engine light on. I can mash the gas and it will SLOWLY accelerate. Also idles pretty rough and struggles to shift out of 2nd. My loud intake turbo noises are gone, my speed is gone, my soul is gone plz help!

Need to scan the car to check for codes. Could be a misfire. OBD 11 or VAG com. Worst case is an auto parts store will scan it for you


Sent from my iPhone using Tapatalk

[949]

is your car remapped?
from which company if you are?
is it hot where you are at?
are you using the A/C?
do you have a sound system?
multiple amplifiers?

[dabarjel]

is your car remapped?
from which company if you are?
is it hot where you are at?
are you using the A/C?
do you have a sound system?
multiple amplifiers?

I have a stage 1 APR tune, I’m in Maryland so it’s mid 80’s around now, I do use the AC, and I have no upgrades to my sound system

- - - Updated - - -

Need to scan the car to check for codes. Could be a misfire. OBD 11 or VAG com. Worst case is an auto parts store will scan it for you


Sent from my iPhone using Tapatalk

I used a buddies scanner and got a code but it wasn’t very specific

[949]

next questions for diagnosing.

how old is the car battery?
have you changed it before?
what brand?
what is the cold cranking amps on it now?

have you jumped the current car's battery (the one in it or the one before it, indicate which)?
who did the jumping?

does your reverse camera flicker once in a while or randomly, when in reverse? similar to a loose cable.

[evo v]

You can also check if your wastegate actuator is seized. This happened to my A3 last year and I got epc and check engine light.

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[o1turbo30v]

epc and cel together are usually spark plug's and ignition coils.

[dabarjel]

next questions for diagnosing.
Car battery is quite new, maybe 3 months, never had electrical issues before, not sure how to measure cold cranking amps I’m only just out of highschool and still learning, I changed the battery myself maybe in February and it’s never been jumped since. Reverse camera works great.

how old is the car battery?
have you changed it before?
what brand?
what is the cold cranking amps on it now?

have you jumped the current car's battery (the one in it or the one before it, indicate which)?
who did the jumping?

does your reverse camera flicker once in a while or randomly, when in reverse? similar to a loose cable.

Car battery is quite new, maybe 3 months, never had electrical issues before, not sure how to measure cold cranking amps I’m only just out of highschool and still learning, I changed the battery myself maybe in February and it’s never been jumped since. Reverse camera works great.

[dabarjel]

epc and cel together are usually spark plug's and ignition coils.

I recently changed my spark plugs, I’m not sure if I did a great job and one of the ignition coils broke so I had to buy an aftermarket replacement. Could that be the issue? I also have rs7 spark plugs in.

- - - Updated - - -

You can also check if your wastegate actuator is seized. This happened to my A3 last year and I got epc and check engine light.

Sent from my XQ-BC62 using Tapatalk

How would I go about this?

[dabarjel]

When I used a friends scanner about a month back, It showed the code PO29900. The problem got worse though.

- - - Updated - - -

When I used a friends scanner about a month back, It showed the code PO29900. The problem got worse though.

[evo v]

P0299 is under boost code. The wastegate is underneath the turbo. You can pull it by hand (when is not hot). If it doesn't move then is probably seized. The pin on the side of the turbo rusts and doesn't allow it to move properly.

Sent from my XQ-BC62 using Tapatalk

[dabarjel]

P0299 is under boost code. The wastegate is underneath the turbo. You can pull it by hand (when is not hot). If it doesn't move then is probably seized. The pin on the side of the turbo rusts and doesn't allow it to move properly.

Sent from my XQ-BC62 using Tapatalk

Will try this when I get off work, is this an expensive fix or one I can do myself or is it a bad situation.

[o1turbo30v]

Just take the car to autozone, they will scan it for free, no point throwing time and $ at something if you dont know exactly what you are trying fix

[dabarjel]

Thank you so much to everyone who’s been helping, I took it to advanced auto and hooked it up to a scanner and got the codes P0299 and P334A. I also have a duralast platinum battery for whoever was asking. Thanks again!

[949]

Car battery is quite new, maybe 3 months, never had electrical issues before, not sure how to measure cold cranking amps I’m only just out of highschool and still learning, I changed the battery myself maybe in February and it’s never been jumped since. Reverse camera works great.

you are slowly narrowing it down with all the possible issues.
that is good.


since you gave me some other info here and read some of your other answers i am knocking out some of the stuff you mentioned.

now,
i would like to now know the exact steps you did to install the battery?
literally, step by step what did you do to install the car battery and what other steps you took?
does the car run now?
does it start up?
do you have a volt meter on your dash like an aftermarket model since the stock car doesn't have one.


with these last few answers, i might have your solution.

[dabarjel]

you are slowly narrowing it down with all the possible issues.
that is good.


since you gave me some other info here and read some of your other answers i am knocking out some of the stuff you mentioned.

now,
i would like to now know the exact steps you did to install the battery?
literally, step by step what did you do to install the car battery and what other steps you took?
does the car run now?
does it start up?
do you have a volt meter on your dash like an aftermarket model since the stock car doesn't have one.


with these last few answers, i might have your solution.

The battery was installed in December. I followed a video tutorial, so I don’t remember but I have never had issues with it since replacement. It worked like a charm after install. The car runs, drives, starts, and no I don’t have a volt meter. The car drives, but again it’s in a limp mode. Thanks again man

[949]

what did the tutorial say to do?

[o1turbo30v]

your fault code P0299 will cause limp mode not a battery....http://wiki.ross-tech.com/wiki/index...3/P0299/000665

[dabarjel]

what did the tutorial say to do?

Took the negative terminal off, then the positive, then removed some mounting screw I think, then put the new battery in, mounted it, positive terminal, then negative, then put the cloth covering back on

[dabarjel]

https://imgur.com/a/JhJUrWt
Here is the link to a cold start with the hood open. Usually you would hear a whooshing or whistling sound from the turbo but now it’s a weird rattle.

[dabarjel]

I got $50 Venmo cashapp paypall to whoever can figure out what I need to replace

[evo v]

Do you hear turbo adjusting when you turn the car off?

Sent from my XQ-BC62 using Tapatalk

[949]

I got $50 Venmo cashapp paypall to whoever can figure out what I need to replace

Took the negative terminal off, then the positive, then removed some mounting screw I think, then put the new battery in, mounted it, positive terminal, then negative, then put the cloth covering back on

The battery was installed in December. I followed a video tutorial, so I don’t remember but I have never had issues with it since replacement. It worked like a charm after install. The car runs, drives, starts, and no I don’t have a volt meter. The car drives, but again it’s in a limp mode. Thanks again man

perfect. i believe I have narrowed it down.
and ill take you up on that venmo offer.


the next part is take that battery and get it "load" tested.
look for professional mechanics. they would have the correct tool to load test an automotive car battery and understand how to use them properly. they will explain to you if the battery is on point. for audi, the battery should not have even a small amount of amp and voltage degradation. so if he says its a little lower or a little less then the battery is not up to par with the car's requirements.

auto parts stores may have it but you'll need to learn how to use them. not sure how inclined you are.




there are three things that I have a theory on that may have been damaged. (but I could be wrong. the car is not here and I cant actually test it completely)
1. your battery is toast.
2. your alternator is on its way out.
3. an electrical problem is there.

it would benefit anyone to have a reliable volt meter at all times as part of your dash. seeing that will really help you know if electrical power is an issue.

so I will go with the first one. all your comments have led to this being the main culprit.
the time frame you installed it with the procedure you did created the pathway to you having damaged the car's battery. the outcome is that the electrical system is now showing its effects. (again its a theory so more testing needs to be done)
so, test the battery.

on audi's and vw's, damage do occur around 2+ months. it all depends on how much you drive and how much demand your pulling.
ill explain more if you find out that the car battery is the culprit.
just remember that audi's electrical system is very picky.



to explain more about load testing car batteries, its explained better in these two short videos.


https://www.youtube.com/shorts/4XDLvRydshA

[dabarjel]

perfect. i believe I have narrowed it down.
and ill take you up on that venmo offer.


the next part is take that battery and get it "load" tested.
look for professional mechanics. they would have the correct tool to load test an automotive car battery and understand how to use them properly. they will explain to you if the battery is on point. for audi, the battery should not have even a small amount of amp and voltage degradation. so if he says its a little lower or a little less then the battery is not up to par with the car's requirements.

auto parts stores may have it but you'll need to learn how to use them. not sure how inclined you are.




there are three things that I have a theory on that may have been damaged. (but I could be wrong. the car is not here and I cant actually test it completely)
1. your battery is toast.
2. your alternator is on its way out.
3. an electrical problem is there.

it would benefit anyone to have a reliable volt meter at all times as part of your dash. seeing that will really help you know if electrical power is an issue.

so I will go with the first one. all your comments have led to this being the main culprit.
the time frame you installed it with the procedure you did created the pathway to you having damaged the car's battery. the outcome is that the electrical system is now showing its effects. (again its a theory so more testing needs to be done)
so, test the battery.

on audi's and vw's, damage do occur around 2+ months. it all depends on how much you drive and how much demand your pulling.
ill explain more if you find out that the car battery is the culprit.
just remember that audi's electrical system is very picky.



to explain more about load testing car batteries, its explained better in these two short videos.


https://www.youtube.com/shorts/4XDLvRydshA

I’m gonna head to harbor freight right now to pick up a battery tester. I’ll run it and keep you updated. If you’re right the $50 is yours.

[dabarjel]

perfect. i believe I have narrowed it down.
and ill take you up on that venmo offer.


the next part is take that battery and get it "load" tested.
look for professional mechanics. they would have the correct tool to load test an automotive car battery and understand how to use them properly. they will explain to you if the battery is on point. for audi, the battery should not have even a small amount of amp and voltage degradation. so if he says its a little lower or a little less then the battery is not up to par with the car's requirements.

auto parts stores may have it but you'll need to learn how to use them. not sure how inclined you are.




there are three things that I have a theory on that may have been damaged. (but I could be wrong. the car is not here and I cant actually test it completely)
1. your battery is toast.
2. your alternator is on its way out.
3. an electrical problem is there.

it would benefit anyone to have a reliable volt meter at all times as part of your dash. seeing that will really help you know if electrical power is an issue.

so I will go with the first one. all your comments have led to this being the main culprit.
the time frame you installed it with the procedure you did created the pathway to you having damaged the car's battery. the outcome is that the electrical system is now showing its effects. (again its a theory so more testing needs to be done)
so, test the battery.

on audi's and vw's, damage do occur around 2+ months. it all depends on how much you drive and how much demand your pulling.
ill explain more if you find out that the car battery is the culprit.
just remember that audi's electrical system is very picky.



to explain more about load testing car batteries, its explained better in these two short videos.


https://www.youtube.com/shorts/4XDLvRydshA

Do you also think it’s possible for the battery to be causing underboost codes? When researching the codes it seemed to be an issue with the wastegate, fuel injectors, throttle body, or MAF sensor

[dabarjel]

perfect. i believe I have narrowed it down.
and ill take you up on that venmo offer.


the next part is take that battery and get it "load" tested.
look for professional mechanics. they would have the correct tool to load test an automotive car battery and understand how to use them properly. they will explain to you if the battery is on point. for audi, the battery should not have even a small amount of amp and voltage degradation. so if he says its a little lower or a little less then the battery is not up to par with the car's requirements.

auto parts stores may have it but you'll need to learn how to use them. not sure how inclined you are.




there are three things that I have a theory on that may have been damaged. (but I could be wrong. the car is not here and I cant actually test it completely)
1. your battery is toast.
2. your alternator is on its way out.
3. an electrical problem is there.

it would benefit anyone to have a reliable volt meter at all times as part of your dash. seeing that will really help you know if electrical power is an issue.

so I will go with the first one. all your comments have led to this being the main culprit.
the time frame you installed it with the procedure you did created the pathway to you having damaged the car's battery. the outcome is that the electrical system is now showing its effects. (again its a theory so more testing needs to be done)
so, test the battery.

on audi's and vw's, damage do occur around 2+ months. it all depends on how much you drive and how much demand your pulling.
ill explain more if you find out that the car battery is the culprit.
just remember that audi's electrical system is very picky.



to explain more about load testing car batteries, its explained better in these two short videos.


https://www.youtube.com/shorts/4XDLvRydshA

https://imgur.com/a/yZY466V
Here is a video of me running the load tester. After reconnecting the battery and starting the car, I got with a TPMS error and a hill hold assist error. They disappeared after driving for 5 minutes and turning the engine on and off.

[949]

https://imgur.com/a/yZY466V
Here is a video of me running the load tester. After reconnecting the battery and starting the car, I got with a TPMS error and a hill hold assist error. They disappeared after driving for 5 minutes and turning the engine on and off.

nice job. your still moving forward.

so for what I can see you are still missing a few more bits of info for a determination

what is the cold-cranking amps of your battery? need this to know which bar your looking at on the meter.
you still need a digital multimeter read out on the battery when you press on the trigger. you would need to know precisely how many volts while the load is running.
when you are doing the video, what is the state of the charge? did you just charge the battery on a tender or just ran it. or has it just been sitting over night and that's the current charge?

[949]

Do you also think it’s possible for the battery to be causing underboost codes? When researching the codes it seemed to be an issue with the wastegate, fuel injectors, throttle body, or MAF sensor

so your asking if the battery is directly causing the issue. kinda and kinda not. ill explain.

what is happening is that the battery, when low will cause the ecm to loose some of its information.
the ecm has three main memory that i know of. I'm sure there are more sub-versions but for simplicity, we can keep it simple for here.
when you have a low or shortage of volt / amp power the memory can get corrupted. that section that holds your remap would be subjected to that error. that part of the ecm that tells what the car needs to do when you driving.

which leads to, can the battery cause the issue? yes but indirectly. once corrupted the car will run with issues as you see now. even if the battery is running fine for now the ecm has that corruption. sample, try reducing the power on your laptop or home PC, it will not run properly.
but for the most part i would say the ecm on audi's needs a specific voltage. i don't know exactly what it is but from experience, if your battery dips below lets say 12.3 or less it can corrupt the ecm programming. why cause if your running the A/C and radio and any other accessories, it will cause the weaken battery to drop even lower. it just needs to be there long enough to cause ecm memory damage.

the corrupted ecm will make it appear that your other hardware is damaged. like the ones that everyone is telling you to replace or repair because of the codes your getting.

the ecm fix is super easy. but you must fix the cause first.
as a preliminary deduction after watching your video, the battery appears that it is sitting at a very low level of voltage. near unstable levels for audi requirements. the gauge is universal so it give a general area of safety levels. hence, if you turn on any other accessories that draw a significant amount of amperage, you will dip that voltage below usable levels. a/c is your higher power consumption accessory. use the multimeter with that load tester to see what the voltage is. if its at or below 12.3 then your battery might be too weak. also if your battery is at a low 12.xx voltage over night, it might be damaged or too weak.

so if you get me the info i mentioned, we can deduce if it is the battery or not.
if it is, just get it warrantied asap. they will get you a new one for free or very small amount of proration. i don't know what your battery warranty states. you'll have to ask them.
once you get a replacement battery then ill show you how to fix the ecm issue.
and most importantly, how to properly install a new battery into your audi. so you wont have the same issue again.

in addition to the load of the hand unit, you should also check the charging system with that new tool you got. follow the manual for that process.

[dabarjel]

nice job. your still moving forward.



so for what I can see you are still missing a few more bits of info for a determination

what is the cold-cranking amps of your battery? need this to know which bar your looking at on the meter.
you still need a digital multimeter read out on the battery when you press on the trigger. you would need to know precisely how many volts while the load is running.
when you are doing the video, what is the state of the charge? did you just charge the battery on a tender or just ran it. or has it just been sitting over night and that's the current charge?

I had just driven the car around for like 30 minutes and ran the test twice before taking the video.

[dabarjel]

so your asking if the battery is directly causing the issue. kinda and kinda not. ill explain.

what is happening is that the battery, when low will cause the ecm to loose some of its information.
the ecm has three main memory that i know of. I'm sure there are more sub-versions but for simplicity, we can keep it simple for here.
when you have a low or shortage of volt / amp power the memory can get corrupted. that section that holds your remap would be subjected to that error. that part of the ecm that tells what the car needs to do when you driving.

which leads to, can the battery cause the issue? yes but indirectly. once corrupted the car will run with issues as you see now. even if the battery is running fine for now the ecm has that corruption. sample, try reducing the power on your laptop or home PC, it will not run properly.
but for the most part i would say the ecm on audi's needs a specific voltage. i don't know exactly what it is but from experience, if your battery dips below lets say 12.3 or less it can corrupt the ecm programming. why cause if your running the A/C and radio and any other accessories, it will cause the weaken battery to drop even lower. it just needs to be there long enough to cause ecm memory damage.

the corrupted ecm will make it appear that your other hardware is damaged. like the ones that everyone is telling you to replace or repair because of the codes your getting.

the ecm fix is super easy. but you must fix the cause first.
as a preliminary deduction after watching your video, the battery appears that it is sitting at a very low level of voltage. near unstable levels for audi requirements. the gauge is universal so it give a general area of safety levels. hence, if you turn on any other accessories that draw a significant amount of amperage, you will dip that voltage below usable levels. a/c is your higher power consumption accessory. use the multimeter with that load tester to see what the voltage is. if its at or below 12.3 then your battery might be too weak. also if your battery is at a low 12.xx voltage over night, it might be damaged or too weak.

so if you get me the info i mentioned, we can deduce if it is the battery or not.
if it is, just get it warrantied asap. they will get you a new one for free or very small amount of proration. i don't know what your battery warranty states. you'll have to ask them.
once you get a replacement battery then ill show you how to fix the ecm issue.
and most importantly, how to properly install a new battery into your audi. so you wont have the same issue again.

in addition to the load of the hand unit, you should also check the charging system with that new tool you got. follow the manual for that process.

Im pretty sure my battery is still under warranty because I bought it quite recently. Im gonna head to harbor freight to pick up a basic digital multimeter and ill let you know the results. Ill test them in the parking lot, then either head to AutoZone if the voltage is under 12.3 to ask about getting a new battery. Ill keep you updated thanks again for the help. The $50 has your name on it :)

[dabarjel]

nice job. your still moving forward.

so for what I can see you are still missing a few more bits of info for a determination

what is the cold-cranking amps of your battery? need this to know which bar your looking at on the meter.
you still need a digital multimeter read out on the battery when you press on the trigger. you would need to know precisely how many volts while the load is running.
when you are doing the video, what is the state of the charge? did you just charge the battery on a tender or just ran it. or has it just been sitting over night and that's the current charge?

https://imgur.com/a/CU4M7Os
Here is a 10 second load test using the voltage load tester I got yesterday and the multimeter that I picked up today. I drove around for around 15 minutes before running this test. I also want to test the charging system, but I need to connect the voltage tester to the battery and then start the car, but I’m not sure how to connect the voltage tester to the battery without removing the terminal cables first, which obviously won’t start the car without a connected battery.

[949]

what is the volt when you just plug the meter on it?
what does it sit at rest.

[dabarjel]

what is the volt when you just plug the meter on it?
what does it sit at rest.

With the car on or off, with the terminals connected or not, I’ll run it now

[949]

terminals connected.
leave car off.

we are seeing if the battery is holding a solid charge.
you don't want to drive it and charge it at this testing phase. batteries that are new like yours should be able to hold its charge for days.
if yours can hold its proper voltage for days, parked and not driven, then it tells you that you don't have any parasitic draws and that the battery is solid. then we can look at other things.

[dabarjel]

terminals connected.
leave car off.

we are seeing if the battery is holding a solid charge.
you don't want to drive it and charge it at this testing phase. batteries that are new like yours should be able to hold its charge for days.
if yours can hold its proper voltage for days, parked and not driven, then it tells you that you don't have any parasitic draws and that the battery is solid. then we can look at other things.

After leaving the car sitting since 5pm yesterday and overnight, the battery sat around 12.6 but idk if my meter was messing up or not but it would fluctuate to as low as 11

[949]

oh wow. is that with it just connected and nothing running?

that's not good.
when you close to 12.4 or 12.3 its a bad sign the battery might be on the way out.

join this site and i can show you more info on what you need to do.

https://www.audis3.org/

[Gberg888]

I have a CEL and EPC light but im throwing the following:

P256300
P256400

My CEL is for a speed sensor in my trans though. Driving around in Limp Mode now...

[dabarjel]

oh wow. is that with it just connected and nothing running?

that's not good.
when you close to 12.4 or 12.3 its a bad sign the battery might be on the way out.

join this site and i can show you more info on what you need to do.

https://www.audis3.org/

I joined, and yes with it just connected and nothing running

- - - Updated - - -

I have a CEL and EPC light but im throwing the following:

P256300
P256400

My CEL is for a speed sensor in my trans though. Driving around in Limp Mode now...

it sucks so bad

[dabarjel]

oh wow. is that with it just connected and nothing running?

that's not good.
when you close to 12.4 or 12.3 its a bad sign the battery might be on the way out.

join this site and i can show you more info on what you need to do.

https://www.audis3.org/

Hey man, I joined the site, how can I proceed, I need to get this fixed soon as possible

[A4Maine-iac]

Wow all this. Limp mode = over boost, saving the car. It is not your battery!! Example, i had my traction control and TPS sensor go off first. 2nd was an under boost. Ended up being the charge pipe to the TB. IMO check you MAP sensor...not your MAF. If you unplug the MAP it 9/10 it will over boost.

If you are going to run these cars and not take to tech you need a ross tech or OBD Eleven Will save you so much $ and stress!. Find someone local who can assist you.