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P1123, P1125, P1128 codes


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I have a 98 Boxster with a 2.5 5 speed and have recently run into a series of CEL on issues. The first time this happened I got code P1125. I reset the CEL and got codes P1123 and P1125 about a month later. I reset the CEL and got P1128 on two different trips about a week later. I reset the CEL and I got P1123 and P1125 a week later.

I looked at the CarChip logs and P1123 and P1125 seem to appear on trips when I drive consistently over 60 mph. The O2 sensors graphs also look odd in that they show consistent output when driving over 60 mph. The O2 sensors graphs normally show a lot of variation in sensor output. I could not find anything related to the time I got the P1128 code.

Any suggestions on where to focus on fixing this issue would be appreciated.

Edited by jporter
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  • Admin

P1123 and P1125 say that your car is running to rich for the DME to compensate for.

P1128 says cylinders 1-3 are running too lean for the DME to compensate for.

Perhaps it's time to check vacuum lines and the charcoal canister (EVAP) purge valve.

Are you sure those are the only codes?

Have someone like Autozone read your codes for free and report back here.

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jporter,

I was having similar CEL problems, reading P1123 & P1125 codes. I did basic maintenance like replacing the air filter element and finding and replacing a loose vacuum line but after resetting, the CEL would always come back on after about 50 miles of driving. I took it to my local mechanic who said it looked like bad O2 sensors. He pulled them and "cleaned" them with a torch but said they probably needed to be replaced for $1200. (I don't think so Tim) After another 50 mi. CEL was back, same codes.

I read many of the related threads here and decided we were still missing something. I tried Mikefocke's proceedure for cleaning the MAF sensor. This made sense to me because it is the first sensor in the chain. If it is fouled or erratic, the computer won't get the fuel/air mixture right. This will set off other sensor faults downstream. When I pulled it out and inspected, the shiny metal sensor pickups were obviously dirty. I cleaned & replaced and reset the codes. So far I have logged over 200 mi. since this repair with no CEL! :D While I never noticed my car running poorly, acceleration does seem a little more crisp now. I think I can put this problem to bed. Give this a try before going any further. I think it is a common problem that is often misdiagnosed.

Thanks to Mikefocke. I think you saved me some $$ on this one.

Edited by Topless
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Topless and mikefocke,

Thanks for the great information. The information in mikefocke's site is clear and informative. Thanks for the lead from Topless and the information from mikefocke.

I will also follow Loren's recommendations as I have followed his post in the past and I have a lot of respect for the information that he and Toolpants provide.

Thanks again to all and I will pass on the result of the efforts to resolve the issue.

jporter

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I tried cleaning the MAF and although it was dirty, the end result is more problems. I used electrical contact cleaner that claimed no residue. I now get multiple misfires that result in flashing CEL. The O2 sensors are now flat-lined with only a spike or two. The CEL does go solid after several seconds and the car runs ok. I'm concerned with cooking the cats as a result of the flat-lined O2 sensors so I plan to order a new MAF :( Any thoughts would be appreciated.

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I'm kind of between a rock and a hard place. I do plan to have AutoZone read the codes, but I'm concerned about the CEL. The CEL only flashes for a few seconds then goess solid. The CEL seems to only flash when I start moving from a stop - once the car is moving the CEL goes solid. I understand that it is not ok to drive the car when the CEL is flashing, but is it ok to drive the car if the CEL is solid after flashing earlier on the same drive.

Incidentally the CarChip reports P0300, P0301 & P0302. I believe these issues are the result of trying to clean the MAF since they were not present until after I cleaned the MAF.

I also drove the car this morning after letting it warm up for a couple of minutes - Although the CEL did not turn on, the car ran rough on idle. I just tried taking the car to AutoZone and the CEL Flashed and went solid as mentioned above so I left the car at home.

Edited by jporter
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jporter,

It sounds like something definitely got goofed up during the MAF cleaning. Pull it back out and take a look. Was it damaged? Residual cleaning solution left behind? Reinstalled correctly? Wiring coupler clean and inserted all the way? Your MAF may have been going bad and the cleaning finished it off. I do not recommend driving the car either until the CEL flashing is resolved.

Edited by Topless
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I also did the Mike Focke method and it fixed my 1123 & 1125 problems perfectly. It has no beem 2 months or more and 1000km with no re-occuring light, so all is well..

You must be careful pulling out the sensor, cleaning it and re-installing it in the correct direction. You didn't put it in backwards did you? Is it pluged in? I know that sounds simple, but if you didn't plug it in all the way etc.. could cause the wierd new problems you received.

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I just received my new MAF - part number 996 606 123 00. I replaced the old MAF and the car runs great. :clapping: I'll post a message if the codes return and try to remember to make a post if they don't reappear.

Edited by jporter
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TECHSPRAY Ecoline Blue Shower. This contains Isopropanol, Ethanol and Heptane. The car has more than 80K miles so the MAF could have been bad.

I use to get a random hesitation when accelerating through 5K revs and this was not present after I replaced the MAF. I must admit that I only drove the car for a short time (20 minutes) and only ran hard through the gears a few times so the random hesitation could still be present.

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  • 7 months later...
  • 4 weeks later...

when i cleaned my MAF it was fine, but after 230 miles it came back on, both 1123 and 1125.

maf was cleaned about 4-5 times thus far.

does anyone have any writeup r procedure to check for vacum hose leak or O2 sensors?

id like to take a look at those at this point

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  • Admin
when i cleaned my MAF it was fine, but after 230 miles it came back on, both 1123 and 1125.

maf was cleaned about 4-5 times thus far.

does anyone have any writeup r procedure to check for vacum hose leak or O2 sensors?

id like to take a look at those at this point

None of those codes would indicate a bad O2 sensor. In this system the O2 sensors report the problem - rarely are they the problem.

If cleaning the MAF helped then chances are you need a new MAF.

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it helped for a while, but code came back.

i dont mind cleaning it at all...would it help if i for instance cleaned it weekly for a few weeks? or would that just cause more problems?

Hi, I had the same problems and CEL always kept coming back on, so i replaced the MAF and so far 1000 miles and no CEL and just the improvement in throttle response was worth replacing it. :clapping:

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I cleaned my MAF and noticed a significant improvement too. I don't get any CEL's so I don't need to replace it - I just cleaned it for the performance benefits, and it worked (and besides, I want to sell the entire engine/gearbox right now to start my project!).

Thanks!

Shash

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  • 8 years later...

I have a 98  and CEL came on codes are as follows

p1128

p1130

p1125

p1123

as what I have read it sounds like MAF, just wondering on the procedure to clean the MAF first then if it is fine and it come back on again I will know I will pretty much have to change out the MAF... I have talked with my Local Porsche dealership they use what is called "Winds air intake cleaner to clean MAF" do you just spray it on the parts of the MAF or use a special rag?? any help on this would be great thanks!!

 

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I have a 98  and CEL came on codes are as follows

p1128

p1130

p1125

p1123

as what I have read it sounds like MAF, just wondering on the procedure to clean the MAF first then if it is fine and it come back on again I will know I will pretty much have to change out the MAF... I have talked with my Local Porsche dealership they use what is called "Winds air intake cleaner to clean MAF" do you just spray it on the parts of the MAF or use a special rag?? any help on this would be great thanks!!

 

Do not touch the MAF with anything.

Use MAF cleaner only other solvents will damage the sensor.

 

IMHO you need to remove the MAF to properly clean it so that you can get the spray cleaner into the channel. Then let it air dry (do NOT blow it compressed air).

 

post-1-0-68274100-1444173648.jpg

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