4 CEL codes, possibly caused by front o2...follow up

[TuRBoTaLooN]

I've had my CEL on since I bought my car, but it seemed to be running ok. Obviously this is because I"m a newb and don't know how my 95 tsi awd should run. I didn't even notice that my 2g bov was broken when i got it and not holding any boost. I felt a world of difference after installing a 1g that actually held boost. Anyway, I took it to Autozone to get the error codes checked because it is free!! After abot 15 minutes of convincing the guy that my car was OBDII, he hooked up the scanner and found me FOUR error codes!! . I was in a hurry to get back to work because I was on my lunch break, but this is what I got from the guy...

1) First code (if i remember correctly ) was P1400, which was something about emissions that I "need to take to the dealer about." I'm assuming this is why I failed emissions at the inspection station on Saturday. (CO was 0.064 instead of 0.050) Not worried about this because I'm getting a new cat-back w/ test pipe setup soon....I hope.

2) Second code he told me was something about the fuel trim that was wrong, but didn't give me specifics on.

3) Third code was something about insufficient fuel supply. Again, that's all I got.

4) Fourth code was something about the idle. The guy said that I'd probably have to "adjust the idler arm." I've been having some idle troubles lately, which I believe I posted in another thread on the newbie forum. Here is a link to that thread . Also, today that problem got worse because the car was idling at 2200RPM!!! I tapped the gas and it went back down to like 1500RPM, but still...this obviously is a problem!


What I'd like to know is if you guys can help me out in any way. What specifically are these codes coming from, and how can I fix them? The one I'm most worried about is the idle problem. It doesn't always happen, but I'd like it to stop idling at like 2000rpm every once in a while. I am not even worried about the emissions code like I said, but I would also like to know what I can do to fix the fuel problems. I'd appreciate any help you guys can give...thanks!


*edit*: I also just wanted to add that my car is pretty much stock. I have a 1g bov, some free mods, and an mbc. That's all that is done to it to the best of my knowledge. I've only had the car for about 2 months now. If you need more info to help me out, just ask and I'll post it. Thanks guys!!

 

[xveganxcowboyx]

You just failed an emissions test and you're not worried, because you're about to throw a test pipe on? You might want to make that a priority. Unless of course I'm missing something about emissions laws that lets you skip the test if you decide you're special and want a performance exhaust...


Not sure about all the codes, but I'm thinking you may have a shit O2 sensor. That could cause bad emissions and fuel problems. Might explain 1,2 and 3.

Insufficient fuel supply is no good either. If it's too short you start to fry rings. Might want to look into that.

 

[ddavisaf]

Well, first thing I would do is ^^^ replace the o2 sensor.
Second thing I would do is get the auto parts store to write down the codes so we can hit the nail on the head for ya.

 

[TuRBoTaLooN]

You just failed an emissions test and you're not worried, because you're about to throw a test pipe on? You might want to make that a priority. Unless of course I'm missing something about emissions laws that lets you skip the test if you decide you're special and want a performance exhaust...


Not sure about all the codes, but I'm thinking you may have a shit O2 sensor. That could cause bad emissions and fuel problems. Might explain 1,2 and 3.

Insufficient fuel supply is no good either. If it's too short you start to fry rings. Might want to look into that.

the reason I'm not worried about emissions is because I am going to put the exhaust on after I get a good sticker. After that, I will just pay someone to get a legit sticker. I was off by so little that I should pass tomorrow. As long as I have an inspection sticker, I do'nt really care...

 

[TuRBoTaLooN]

I am 99% sure these are two of the trouble codes:

P0125.....Excessive Time to Enter Closed Loop Fuel Control.
P0170.....Fuel Trim Bank 1.

I read on a post that these problems can be fixed with a sensor that is near the intake manifold??

 

[TuRBoTaLooN]

Ok, so I did a little research and this is what I came up with.

3 of the 4 codes I have are
P1400
P0125
P0170

I have determined that i need to replace the thermostat and possibly an O2 sensor, but I don't know which one I need to replace, and at like $100 a piece, I can't afford to replace both unless it's necessary. Thanks in advance for any help.

 

[TuRBoTaLooN]

Ok, so I have to apologize for wasting space on this forum. I did search very briefly for some answers, but used dumb keywords to search and found limited answers. I had some time today and began a more extensive search for these error codes.

Turns out that the front o2 sensor usually will throw 2 or 3 of these codes that I am getting so that is the first thing to replace. Some people have said that the P0125 code can be thrown by a stuck thermostat, so for $10 I will replace it anyway. My buddy just got a logger, so I will hook that up as well before and after and try to post some more information.

Also, for the P1400 code, many people have said that the manifold differential pressure sensor is dirty and needs to be cleaned. Most of the time it doesn't need replacing, so I will just unplug it and clean it.

Other possible scenarios include an exhaust leak, boost leak, or any other condition that may cause the car to run too rich or too lean to the point where the ecu is unable to adjust for it. The fact that I am getting horrible gas mileage makes me believe that it is running rich and I am hoping a new o2 will fix this problem. Again I apologize for not searching, but I will post as much detail as I can after I fix these problems so others may use this as a reference. Thanks guys!

 

[xveganxcowboyx]

You're definitely on the right path.

Diagnosing more than one problem at a time is always hell. You know the O2 is bad so do that first. Then drive it some and see how it runs. Any other problems will be much easier to diagnose with the O2 problem out of the way.

Don't forget to clear your engine codes by pulling power for a little while. That way if it pops any more you will know they aren't just carry-overs.

 

[TuRBoTaLooN]

Well I picked up a new o2 sensor for about $60 at the local autozone, and this weekend I planned on installing it and post about how that went. Unfortunately I was unable to get the old o2 out of the exhaust manifold, and my friend who works at Acura tells me that he usually has to take a blow torch to it to get it out. Anyone have any tricks or tips on how to get it out??? If not, I just plan on taking it to a local shop to have it done. Then I'll post up on what trouble codes went away.

 

[Attack Eagle]

yep. get the proper socket,

1 spray it with pb blaster while cold...

2 crank it up and drive it to work/where ever... spray it again while hot.

3 spray it when you leave and when you get home...



repeat for a couple of days... then try taking it out with the manifold HOT not cooled off.

 

[TuRBoTaLooN]

Ok, I finally got around to getting the front o2 sensor replaced (took A LOT of elbow grease). I also replaced the alternator belt and rear brakes and installed a new 2.5" catback exhaust with a test pipe. Currently the rear o2 sensor is in the exhaust, but the wires are not connected. I took it to Autozone again to check trouble codes and this is what they found:

P0136 o2 sensor circuit malfunction (Bank 1 sensor 2)

P0141 o2 sensor heater circuit malfunction (Bank 2 sensor 2)

P1400 Manufacturor Control Auxiliary Emission Controls

Now I'm assuming the P1400 code is because I don't have a cat, and possibly b/c of the rear o2 not being hooked up. But I don't know and can't find out if the P0136 and P0141 codes refer to the front or rear o2 sensor?? In case it helps, I replaced the front o2 with a Bosch sensor and had to splice the wires to connect it. It did not plug in to the wiring harness. Is it possible that I connected a wire or two incorrectly?? Please guys, any help would be much appreciated. I have searched other threads, but did not find any answers as to whether its the front or rear o2. Thanks guys!

 

[Attack Eagle]

hook the sensor back up... looks like both are rear sensor codes.

or follow the VFaq bypass instructions.

 

[TuRBoTaLooN]

I hooked up the rear o2 sensor last night because I was desperate to get rid of these CEL codes. I connected the battery again, started the car...let it sit for a good 10 mins. Vuola! No more CEL!!!!! So as it turns out, one bad o2 sensor gave me all this trouble. I think this would be a good thread for others who blow an o2