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View Full Version : "17544 - Fuel Trim: Bank 1 (Add) : System too Lean P1602 - 35-10 - - - Intermittent"



mrsvanur1
09-22-2009, 05:41 PM
As the title states. My car is throwing this code. Does anyone know where i should start looking? At idle, my boost gauge is reading approx. 20 inHg and i have NO Boost.

Seerlah
09-22-2009, 05:59 PM
P1602 is for the removal of battery cable. No biggie.

P1136(17544) would be either your MAF or leak in your secondary air injection system (Ross Tech says it could also be an exhaust leak, so).

mrsvanur1
09-22-2009, 06:08 PM
Well i know my MAF is good. This could be a potentially bad question but could the problem be from a poor seal between the hot side of the turbo and the cat? I think the tech did a shitty job sealing it. Is there a way to make a good seal without using a gasket? Ive heard that that gasket isnt necessary.

Seerlah
09-22-2009, 06:14 PM
The gasket is not necessary, but could cause an exhaust leak. I would personally replace the gasket if you feel the mechanic did a sh*tty job. It is on BT applications that you don't want to use a gasket there. Too many people had the gasket come apart and enter into the turbocharger.

I think it was walky_talky20 whom had the same issue and ended up having it to do with something with the SAI. Hopefully, he will cimme in or you could PM him and inquire.

mrsvanur1
09-22-2009, 06:26 PM
Ok cool, i Pm'd him...would you mind talking more about how it could come from the SAI?

Seerlah
09-22-2009, 06:29 PM
It will be a leak in your SAI system somewhere which could cause you to run lean.

mrsvanur1
09-22-2009, 06:52 PM
how would i go about fixing that?

Seerlah
09-22-2009, 06:54 PM
It is usually a common issue and you would just need to replace a certain part. I just don't know which one, but walky_talky20 should know.

walky_talky20
09-22-2009, 11:28 PM
It is usually a common issue and you would just need to replace a certain part. I just don't know which one, but walky_talky20 should know.

Wow, I wish I had a crystal ball, but sadly I do not. [rolleyes]

System too lean (Additive) means the car is running too lean at idle and the Idle fuel trim enrichment is maxed out (or at least above the threshold to throw the code).

The most common cause for a lean @idle condition is the signal reading from the Mass Air Flow sensor is too small - thus requiring the idle fuel trim to go sky high to compensate, hence your code. This condition can be caused by 2 separate things. First, the MAF sensor is dirty or failing, and is resulting in low numbers (i.e. - air is passing through the sensor, but it isn't counting all of it properly). Second, there is a vacuum leak allowing unmetered air into the system (i.e - some air is bypassing the MAF altogether which is causing the low numbers).

A vacuum leak at idle can also be a boost leak, depending on where it is. A boost leak test would be a good starting point to find leaks. A thorough inspection of all the intake and vacuum hoses is a good idea too.

If you have a laptop and vag-com available, there are some more steps you can do to try and narrow down what the problem is. For example, if the Multiplicative fuel trim is high (and positive), it is probably a bad/dirty MAF because the ECU is just adding fuel all over the map. If the Mult. trim is very negative, it is probably a boost/vacuum leak - fuel is added at idle and pulled back at boost. You can also log the MAF directly to see what's going on.

Seerlah
09-22-2009, 11:34 PM
Ha said that his MAF is good, and Ross Tech says that it could be a leak in his SAI. To the OP, to verify the MAF is still good you should log it. You will more than likely be placed into limp mode once you reach the higher RPM, so just be prepared for that. You can get out of limp mode by resetting your ECU (remove negative battery cable for around 15 min, replace cable and do throttle body adapt). You should have your radio code handy if you want to do this. if you don't, then you can reset the ECU via VAG Com.

Edit: Just noticed you are already in limp mode

walky_talky20
09-22-2009, 11:43 PM
Ha said that his MAF is good, and Ross Tech says that it could be a leak in his SAI. To the OP, to verify the MAF is still good you should log it. You will more than likely be placed into limp mode once you reach the higher RPM, so just be prepared for that. You can get out of limp mode by resetting your ECU (remove negative battery cable for around 15 min, replace cable and do throttle body adapt). You should have your radio code handy if you want to do this. if you don't, then you can reset the ECU via VAG Com.

The car is a 99.5, does it even have SAI? I thought that was 2000+ only.

Seerlah
09-22-2009, 11:45 PM
I did not know that.

walky_talky20
09-22-2009, 11:52 PM
I though the AEB's didn't have SAI, but I might be wrong on that. I doubt it would be an SAI problem anyway. If the vacuum hose to the SAI combi valve was the problem, there would certainly be a code for that (incorrect flow). The other possibility is the combi valve is stuck open. That may be able to cause the O2 to read lean in error, but I think a dirty MAF or a vacuum leak is much more probable.

It really could be a bunch of things. Some codes are pretty specific and you can just point to the problem, but this one is pretty broad.

Seerlah
09-22-2009, 11:56 PM
To the OP, when did all this start happening? I would clear the codes, reset the ECU, do a throttle body adapt, and log the MAF. Have your radio code ready.

mrsvanur1
09-23-2009, 07:26 AM
Well i haven't had boost since i got the car from the tech in late july. When i got it, i had the code and my car wouldnt and still wont go into boost. Im beginning to think that the problem is because of an exhaust leak because it looks like the mechanic did a horrible job trying to use liquid gasket. So im gonna try to patch that up today and how do i go about cleaning the MAF and getting the car out of limp mode?

mrsvanur1
09-23-2009, 07:32 AM
Im sorry but what is the throttle body adapt and how would i go about getting my radio code?

Seerlah
09-23-2009, 08:30 AM
You can't patch up the gasket for the cat to turbo, because there is not an RVT gasket sealer that can withstand that heat. You will need to replace the gasket altogether. I suggest to use PB Blaster on the bolts before attempting to remove them.

There is a card that came with your car which has the radio code. If you don't have that card, then you would need to get it from a dealership. But they charge a pretty penny for it. There is a member on here whom can get it to you for free. I will try and find his user name so you can send him a PM and ask him if he can get it for you.

To clean your MAF, purchase CRC MAF cleaner from your local autoparts store. Take the MAF out of the air box and follow the directions on the bottle. You basically just the spray the element sensor which is located near the middle of the sensor housing. After you do this and replace your turbo to cat gasket, you will want to perform a boost leak test. This is to ensure that you have 0 leaks. Once all this is done (and you have your radio code handy), remove the negative cable from your battery for battery for roughly 15 minutes. After that, place the negative cable to the battery back on. You will need to perform a throttle body adapt, or else your RPMs wil be all over the place upon start up. To do this, just place the key in the starting position (without cranking, all lights on dash should be illuminated) and leave it in that position for 10 min (I do it for this length to ensure it gets done). Take key out ignition, insert again and start as usual.

Once your car is running let it get up to temps, because you will want to do a WOT run off the back in case you get placed back into limp mode. You would need a VAG Com at this point. Log block 003 to read the g/s for the MAF. This will determine if you have a good, faulty, going out, etc MAF.

If you don't have a VAG Com, do what I just told you minus the logging of the MAF because it still may work. If you need to know how to perform a proper boost leak test, this is the procedure I use (http://www.a4mods.com/index.php?page=webcontent/pages/boostleak.html). A VAG Com will really be helpfull in this situation. I have a feeling you have intermittent codes which may help make diagnosing easier. If you don't have VAG Com, you should post in this section (http://www.audizine.com/forum/forumdisplay.php?f=22) to ask if someone with a VAG Com can help you diagnose your issue. Most people on here are freindly, for the most part. So, someone will more than likely let you use their VAG Com if you don't have one.

mrsvanur1
09-23-2009, 09:23 AM
Sweet! Thanks alot. Just got back from autozone with the cleaner and cleaned the Extremely Dirty MAF. I remembered that i cleaned my filter not too long ago and didnt clean the MAF. Ill replace the gasket soon and post more news. thanks again.

mrsvanur1
09-23-2009, 09:36 AM
I replaced the gasket. I now have a clicking sound when i accelerate! Could this be because i have an aftermarket cat and the gasket just isnt seating properly?

Seerlah
09-23-2009, 09:39 AM
Where is the sound coming from?

mrsvanur1
09-23-2009, 09:42 AM
Around the cat. There was no gasket there when i went to put the new one from audi in. and i didnt have the sound before. It looked like the tech just tried to use liquid sealant.

Seerlah
09-23-2009, 09:51 AM
I would not be surprised if that liquid seal turned into the hard substance that it is supposed to do, and a peice of if got sucked back into the compressor. And that noise is a peice of the hardened sealer inside your turbocharger. This is just speculation, though.

Maybe remove the cat and take a look inside of the turbo from the hotside and see if you see anything. And when I say anything, I mean anything. If so, remove it, check for any damage to the wheel, and shaft play.