I had my dealer look at my CEL while I was also getting something fixed. I have the following codes:

P0420 Catalytic Converter Effect is insufficient

P0172 Selfadaption of mixture formation, The mixture is too rich in the part load range.

Selfadaption of mixture formation at rich stop, tendancy of engine towards 'lean'.

P0130 G3/2 (o2 Sensor upstream of cat), fault in )2 sensor signal because O2 sensor heater switched on or off.

My service advisor told me since it is an aftermarket header/cat he cannot do anything. I have a Kleemann header/cat installed. Should I just replace the O2 sensors and see what happens? The car feels and sounds perfectly normal with good gas mileage.

 

Hi,

This may be related to the cam sensor issue I was having. (yes, this seems to be the cause of a LOT of seemingly "unrelated problems")

 

Suggest you speak with Cory at Kleemann...

 

I spoke with Cory at Kleemann. He suggested replacing the upstream O2 sensor and possibly relocating the rear O2 sensor a little further down the exhaust pipe. The car has 47000 miles on it, so maybe it was due anyhow.

 

you don't have to relocate the exhaust O2, there's another easier way !

 

And that would be to...???

 

I would check still regarding the cam sensors as others have said. Mine had issues around the same mileage and kept throwing the o2 code. Turned out it was the cam sensors leaking oil into the wiring harness. Pop them and look at them before you relocate squat mang.... good luck.

 

I had the cam sensors and isolating wires done late in March. The dealer reset the service light then. Out of the blue, the CEL light popped ON again. I bought new sensors, but I have to install them tommorrow. I kinda hoped that the CEL would not have reappeared after the reset.

The car doesn't run any different with/without the CEL. I have been getting around 22-26 mpg all-around, so I hope that the mileage may go up after I install the new O2 sensors. I did notice, however, that the exhauset is a little black, like it has been running rich.

I have been meaning to get the ECU tuned, but Speed Inovations said their guy had left and they weren't doing the ECU tuning anymore

I will definately post any changes after I install the sensors.

 

Well, I changed the O2 sensors. It took a whole 45 minutes including removing and installing the belly pans. I started the car and the CEL light is still on. Does this need a few start/stop cycles to clear out? If not, I net to do some more trouble shooting.

 

Did you reset the CEL? (With OBD2 reader)
They don't generally go off by themselves.
Maybe you just need to clear it.

The 02 sensors typically last a long time.
Service interval is 100K though people around here have been known to keep them much longer.

I did the upstream one on my car, but not the downstream one.
(Damn, they want like 250 for it, and thats the discounted price)
Got the upstream one for 110.
It's the one that determines fuel ratio etc.

The ECU compares the output from the 2, they should be quite different.
If they are 2 close to each other, thats when you get an error.

 

I disconnected the neg battery cable for a minute or two and then reconnected it. Started the car and the CEL was still on. Damn! I don''t want to go to the dealer if I don't have to. I may swing by an autozone to have them pull the code to see if it is still the same codes. I was under the impression that the code readers don't clear the faults.

I will keep the old O2 sensors just in case down the road...

The car still runs the same, but the mpg has gone to about 26-29 all around driving.

 

With the engine running listen between the air box and the cylinder head in that gap. If you hear a loud hissing noise then you have a leaking crankcase breather hose.

Easy fix, about $15 for the hose. So many have failed that the part was nil stock in germany for a while.

 

Autozone will be able to clear the code. Nothing short of manually clearing the codes will work. I've had the P0420 myself many times. Have always replaced the downstream 02 sensor, but since the car was in for something else, had them look at the cam sensor. And what do you know, it's leaking. So, I'm hoping that that's the source of the problem, and that it will be fixed.


What I did was install a Scangauge in my ashtray - it fits in there with little modification, and now I can read/clear codes on the fly myself. I drove down to Savannah in Feb (Crab Shack is awesome, btw) and had to clear the same code (have since replaced the 02 again) at least 10 times on the trip. You should invest in a reader, it's worth the small amount of money.

 

Just thought I'd add some information to the thread in for future reference.

Rockauto is a good source for inexpensive O2 sensors. You can get Bosch OE type for 109.79 for upstream and 193.79 for downstream. It's relatively easy to find 5% off coupons too.

 

I'd like to see a pic of that.
Is there one posted around here?

 

No, it's on the down low.

Once I get my car back, I'll slap up some pics. It's also a great digital gauge set up as well; I've got it on rpms and volts, and two more spots that I have to see if there's anything worth knowing the value of that it can read off the OBD port.

 

Generally anything that triggers a CEL (not other stuff like SRS)
can be reset with a standard OBD2 scanner.

It's the law, at least in the US, that certain engine functions have
standardized data, and ability to reset with standardized tools.

Yes, other stuff you can't reset.
But long term, an OBD2 scanner is essential, and you'll make new friends too! (I've reset a number of CEL's for people)

Going to the local autoparts store, they are pretty damn expensive,
but here you can get a decent one pretty inexpensively.
I keep in the glove box, along with extra fuses.
And I keep a basic toolkit, with metric sockets, and inverted torx,
torx, screwdrivers, wrenches and pliers, etc. JUST IN CASE.
Also I keep an extra coil pack, as they seem to die at inconvenient times,
and while online they're 35 bucks, the dealer charges 65.

I have this scanner for 56 bucks but you might need one with CANBUS.

I'd say pull out the MAF and clean it also, as that is another item that helps determine FA ration.

Yeh, I'd keep the 02 sensors, i doubt there's anything wrong with them.
And like every says, check for the dreaded oily wiring harnesses.

 

My SA at Fletcher Jones Imports in Las Vegas was kind enough to reset my CEL as a courtesy. Got a cup of Starbucks while I was at it! I will clean the MAF this weekend. And I will check into the scanner as well. Thanx for the help my fellow members

 

http://www.harborfreight.com/
item 94169 scanner $39 obd2 with can reads clears and reads i/m codes.
The point a lot of you are missing is that unless you fix the problem,clearing the code will just clear the light and leave the underlying condition stored as pending.The damage that is being done by the uncured condition still exists.No matter if you clear it 10 times in a trip,the effects of the faulty part are still doing harm.If the problem that tripped the cel is truly repaired, after several drive cycles that the condition no longer exists the cel will clear itself.Just erasing a code to clear the light or unhooking the battery to clear the light will still leave the unsolved condition as a pending code in the obd2 system and your car will still fail any smog test.
hb tools will meet the 39 dollar price in store if you take the ad from their online site.
ohlord

 

I don't really see anyone saying that he should clear the codes, and just pray that it doesn't happen again without doing some troubleshooting afterwards. There is a base level of intelligence that is assumed in a car forum.

 

While it's possible some damage could occur, it's also possible that
errors can occur just once, and be a random electrical gremlin.

I thought about suggesting that, but he'd already replaced the 02 sensors.
So shame on me? I don't see an issue with clearing a code and seeing if it comes back. If it happens once, you clear it, and it doesn't come back, then things have returned to within normal operating parameters.

He has several codes though, and it will be interesting to see if they come back, and if they are the same codes or different.

I'd still be keep a close eye though, do some research, and look for possible causes for an intermittent error.
Hard failures are the easiest to identify.

The shotgun approach to intermittent problems can work, but can also be expensive. But definately clean the MAF, get some cleaner, and blow it out.

I've been in the business of fixing all kinds of computer and mechanical things and/or supporting or teaching, and managing about said stuff most of my life.

I've fixed more stuff, just showing up, than any other way.
I call it the "laying on of the hands".
Machines know when the guy who knows how to fix them is in the vicinity.
They conspire to not fail in your presense, and both you and the customer know the problem will occur once you are precisely 5 or more mile from the customer site.

As a professional in the field, too many trips to repair the same piece of equipment can result in making you look bad, so you tend to replace as many parts as you can get away with on a problem piece of equipment or with a problem client (who is calling your boss etc.)
But as a private citizen, I'm willing to troubleshoot a piece at a time,
save some dough, and suffer the consequences to find the exact problem, as long as it's not inconveniencing me too much.

In his case, the car is running fun, just these odd CEL's.
I would've cleared it, see what came back, cleaned the MAF, visually inspected closely the wires, harnesses, (Oil?) and the 02 sensors to be certain the insulation hadn't worn away at all, or shorted.
If still getting codes, I would maybe try disconnecting the maf to see if anything changed.
And then if nothing changed, then would I replace the upstream sensor, and then the downstream.
That being said, I replaced mine as a maint item with no problems, because
it was the correct interval to do so, and dammit, even 1 mpg difference is bux these days.
But he's only at 40K miles, and thats pretty early to have an 02 sensor fail.

A lot of times when troubleshooting, it's like you're looking at what changes, or is different as you try different things.
Those clues become pieces to the puzzle, and while at 1st you may have started without a clue, the pieces start to come to together, and you see a pattern, apply logic, construct a theory, and then test to see if it's the
the actual issue.

I used to wake up in the middle of the night, suddenly realizing the solution to a problem that eluded me, either in hardware, or software.
It's a gift and a curse...

 

That's very true as well. I've seen many times here a random cel comp up, then never come back after it's been cleared. cylinder misfire ones come to mind.

 

Have you ever swapped you cat?
Cyl 1 seems to be the one that triggers most frequently in that situation, though oddly the majority of my coilpack failures seem to happen on cyl 2.
Maybe more heat accumulates there?

Ok, not to hijack the thread....sorry.

 

So far no codes came back..I actually have a little over 51000 miles on it now. I will clean the MAF sensor for sure. Will having the header and high flow cat cause the lean condition to the point where the injectors are maxed out? I am looking for for an ECU tune to fine tune the engine. Well, and a pulley at some point in the future also.

 

I would get the pulley first before deciding on who to do the ecu tune just so that you don't have to do the ecu tuning twice.

assuming CEL didn't come back on after you changed the O2 sensor? there was a discussion on the 32/55 forum that if you had removed the secondary cat and triggers the CEL you can space the O2 sensor out so that the sensor doesn't sit in the main stream of the exhaust flow and that would solve the problem with triggering the CEL.