Advice for CEL coded P1128 & P1130

[skip_168]

Originally Posted by 2000SoCalBoxsterS

I have a code reader and a list of the definitions for these codes from three different sources. Typically I've seen advice that these CEL codes are probably a bad or dirty MAF. But my question is, why does the actual code definition say it involves my O2 sensors? Should I replace all four of my O2 sensors? I hear they are about $130 a piece.

I cleaned my MAF today what are the chances that will take care of my CEL problem?


The MAF. This thing cost $250 online $400+ from the dealer! I sprayed electronic parts cleaner on the contact points. The paper clip looking thing.

The codes 1128 & 1130 are for each individual bank running lean, or that the ECU cannot control the mixture properly, (1128 is for 1-3.., 1130 is for 4-6.. or something like that..).

The fact that the code descriptions say "O2 sensors.." is not representative of the total number of conditions that need to be met to set the codes. The codes are an indicator of the affected system, not for an individual component. It is still up to the technician to properly diagnose the problem, and repair...

I had the same codes poping up on my 2000 boxster for about 8 months.. I used to be a mechanic for Porsche untill 2000 when I got my degree in electrical engineering, so now that I sit on my arse & play with electronics all day, I really didn't want to tinker with the car. So, out of lazy-ness, I tried the first thing that seemed to make sense, clean the MAF & drive it around fer a week or two.. that fixed my problem... its been a year and no CEL...

So, from my expierience, clean the MAF.. & drive...

if the code resets, well then you gotta start testing the system...

Start with the obvious first, vacuum leaks. check the plastic plenum real good, I have seen a few split or crack & cause a temperature sensitive leak..

since both codes set, what ever it is, it is common to both banks.. (on this alone you can rule out the O2 sensors..)

[2000SoCalBoxsterS]

Thank you Skip, I really appreciate the advice. I did clean the MAF and installed a new air filter. Then the weather turned really crappy and I have not had a chance yet to test drive it. Tomorrow should be my first opportunity.

I'm a little worried that maybe it wasn't the MAF only because the MAF looked clean at least with the naked eye. But I did clean it with the electronic parts cleaner so I hope that does it.

It funny how the PCA.org site can be inconsistent with their Tech advice. I saw one Q&A answer dated 2004 where the Tech said never clean a MAF that will not fix a dirty MAF. Then in 2006 the same Tech answered the could my MAF be bad question with "try to clean it first with electronic parts cleaner, that that often fixes the problem."

They also told me No 19" wheels they will rub your wheel well liners through. And again, the folks here with 19" wheels and the same year Box as mine disproved that advice.

I'm gald I have you all as a check & balance. Thanks!

[NickCats]

For what it's worth, here's my experience with cleaning the MAF after I got codes P1123 & P1125 last year :

http://986forum.com/forums/showthread.php?t=11810

P1123 Oxygen Sensing Adaptation Area 1 (Cylinders 1 - 3) - Lean Threshold

P1125 Oxygen Sensing Adaptation Area 1 (Cylinders 4 - 6) - Lean Threshold


P1128 Oxygen Sensing Adaptation Area 2 (Cylinders 1 - 3) - Rich Threshold

P1130 Oxygen Sensing Adaptation Area 2 (Cylinders 4 - 6) - Rich Threshold


Nick

[2000SoCalBoxsterS]

Originally Posted by NickCats

For what it's worth, here's my experience with cleaning the MAF after I got codes P1123 & P1125 last year :

http://986forum.com/forums/showthread.php?t=11810

P1123 Oxygen Sensing Adaptation Area 1 (Cylinders 1 - 3) - Lean Threshold

P1125 Oxygen Sensing Adaptation Area 1 (Cylinders 4 - 6) - Lean Threshold


P1128 Oxygen Sensing Adaptation Area 2 (Cylinders 1 - 3) - Rich Threshold

P1130 Oxygen Sensing Adaptation Area 2 (Cylinders 4 - 6) - Rich Threshold


Nick

And what was the end result? Did cleaning the MAF in your case fix the problem?

[NickCats]

So far, so good ( now watch, I'll bet the CEL lights up on the way home )

Nick

[skip_168]

Originally Posted by NickCats

So far, so good ( now watch, I'll bet the CEL lights up on the way home )

Nick

hahaha... yep.. instant karma is a bish...

[fullthrottle52]

These codes have been discussed here many times.

Again, Go get a smoke test for any leaks. When I had these codes my indy found a leak in the oil fill tube. Light came back on again. Put in a new MAF and problem fixed. No CEL at this point. Probably both issues together were causing the CEL. You have to start somewhere and a smoke test is the place to start.

You do have to clear the codes to see if they will come back.
Cleaning the MAF does not work unless it is really dirty and looks like it needs cleaning. If you clean it, it may last for a couple of weeks. After several start and run cycles it more than likley will come back on.