Oxygen Sensors/ Air Mass Sensor

[portsrn]

my CEL came on and it read P1124(?) P1125(?)-dont exactly remember but it pointed out to (2) O2 sensors before the cat . i replaced them but only after 7 miles of driving, the light came back on. should i then put back the 2 OEM Porsche O2 sensors at the back and put the old ones back OR just replace the rest? someone said that it gave the wrong code and its definetely the air mass sensor. my 97 Boxster has 91 K miles. can someone enlighten me? TIA

[Loren]

You DO NOT have any problems with your O2 sensors.

If you have:

P1124 Oxygen Sensing Adaptation Area 1 (Cylinders 1 - 3) - Rich Threshold

What this is telling you is that the mixture is too lean and the DME can not male it rich enough.

Usually this means you have an air leak or a bad MAF. Either way your DME thinks there is too much air and not enough fuel.

[infocusf8]

Porsche shops make a ton of money from replacing O2 sensors that are not bad because the most common fault code that comes up points to the O2 sensors. Some shops even recommend that they be changed at certain service levels such as 60K miles and Bosch recommends changing them at 100K mi. There is not much to them and the test to see if they are functioning is a voltage resistance test that can be done by any muffler shop much more cheaply than a Porsche dealer or certified shop. As was suggested in another post think of them as the nose of your cars exhaust system in that they sniff the pre cat and post cat mixture and report back to the ECM what they smell. If what they smell isn't up to emission standards a fault code is reported and store for a few cycles then the CEL come on if the fault is not cleared up by repair. The problem though is rarely with the O2 sensors as it generally occurs further down the tree and that is why there are set procedures starting at the top of the tree and working down. I had fault codes that indicated the O2 sensors but the problem turned out to be a pinhole intake leak in the air/oil separator bellows. Find a good mechanic that you feel you can trust and let them run the proper diagnostics on your emission system to determine the problem.

[portsrn]

You DO NOT have any problems with your O2 sensors.

If you have:

P1124 Oxygen Sensing Adaptation Area 1 (Cylinders 1 - 3) - Rich Threshold

What this is telling you is that the mixture is too lean and the DME can not male it rich enough.

Usually this means you have an air leak or a bad MAF. Either way your DME thinks there is too much air and not enough fuel.

sorry guys,

i stand corrected....the codes were P1123 and P1125 even after replacing all (4) o2 sensors within 10 miles...should i just replace the MAF? i'm getting really frustrated going back and forth to the mechanic's shop

thanks

mike

[Loren]

Um... I told you it was not the O2 sensors.

As I said look for an air leak and test the MAF.

Either you have a large air leak or the MAF is not changing with air flow.

[infocusf8]

After going around and around with emission codes that all pointed to my O2 sensors it was not the O2 sensors. I had an intake air leak in the rubber bellows from the oil/air separator (an $18 part) and a leak in the vacuum tank on the secondary air system (about $40) both are common wear items because they are cheap and exposed to a lot of heat and stress. The leaks were found by doing a smoke test so you might think about having one done.

Edited April 1, 2010 by infocusf8

[emcauliff]

He didn't read a word you so thoughtfully put to paper Loren.

[CalSierra986]

HI guys,

I bought a 97 boxster last year.  Since I am in CA I have to keep the CEL off to pass smog testing.  After purchase I replaced the MAF after reading the codes.  It went away long enough to pass after a drive cycle and came back 2 months later.  I have seen P1124 and 1126 almost every time I have cleared the DME.  The last code of interest was P0441.  I inspected and gas cap and replaced the evap purge valve at the fuel cap.  After driving a few days, the CEL is back with the code P0102.  Next I plan to change the oil and spark plugs as good measure.  Any ideas or do I need to do a smoke test?  I should mention, the only symptom has been hard to start once in awhile and the car runs fine.

Edited April 14, 2016 by CalSierra986

[Ahsai]

Is it a Bosch MAF with the correct p/n and is the intake stock?

[ziomster]

Hello gentlemans

 

To not start new subject i will post my question here.

From some time i have a problem with a performance of my 2002 Boxster S, in the past I have a Boxster 2,7 which was way better perform than actual one

 

I have a combination of following faulty codes: P1117, P1118, P0134, P0140 and P0160

 

Can you please indicate me what can be a problem? Where should i look for problem?

 

thanks in advanced for your help

/Dawid

[Ahsai]

All your codes are O2 sensor related. Have you checked the fuse for the O2 sensor heaters? Do you have a scanner setup that you can use to monitor O2 sensor voltage?

[ziomster]

hi

 

thank you @Ahsai for your post:) From different sites in the internet i know that this errors are related with o2 sensors.

Torque app shows only one sensor working - rest are dead (no changes in n the voltage diagram) - which is also strange (rarely 3 lambda sensors dies at once). That is why i still have doubts.

I know also that sometimes combination of errors might have "other" reasons - taht is why i'm asking more experienced users

 

I already plan to buy 4 new one - from Bosch retailer i got one part number 0258 003 806. Is it correct one? Somewhere i read that there should be two types of sensors

I will check fuse responsible for heating sensors tomorrow. 

 

Today i found also one thing which makes me thinking.

I had left air in intake - one of the steel strap was broken and engine was taking some air throw this hole

With such condition engine work more or less correct but was weak.

When i fix it some problems on low rpm appears - engine has problem to come to higher rpm. Engine shakes on idle. Once i heard shoot into the intake.

 

This might confirm bad o2 sensors? 

 

Once again thanks for any help

 

/Dawid

 

Ps. Can you tell me how spark plugs should be connected - in what order? I have bad feeling that last mechanic which was touching this car could connect them wrong.

Edited June 10, 2016 by ziomster

[Ahsai]

When you said the O2 sensors are dead, what constant voltage did it give? It makes a difference. Was it about 0.44v or 0v? Check pin 1 of all sensors (black cable) if you get 12v with key on engine off. 12v is the power to the hearing element of the sensor. Then check pin 4 of each one and see if you get any voltage. You should see about 0.44v with key on engine off.

 

Your precat sensor should be this one https://www.amazon.com/Bosch-15182-Oxygen-Sensor-Fitment/dp/B000CF1VGA/ref=sr_1_3?s=automotive&ie=UTF8&qid=1465602133&vehicle=2002-2-18-87--8-6-7-1140-40-1-1---25-0&sr=1-3&ymm=2002%3Aporsche%3Aboxster&keywords=bosch+oxygen+sensor

 

Postcat sensor this one https://www.amazon.com/Bosch-15183-Oxygen-Sensor-Fitment/dp/B000VAZKP4/ref=sr_1_1?s=automotive&ie=UTF8&qid=1465602667&sr=1-1&keywords=bosch+oxygen+15183

 

Your spark plug wires are most likely fine. If they are not, the engine will run very rough all the time. 

[ziomster]

I will check this voltage and make a screen of app results next week 

 

This o2 sensor which you link are the same with 0258005182 and 0258005183 Bosch numbers?

In my country i cant find numbers which you type (15182 and 15183):/ 

 

thanks

/Dawid

[Ahsai]

Sorry but I'm not familiar with those longer BOsch p/n's. Your precat and postcat sensors should be #26 and #27 (look for the correct year), respectively here.

 

http://www.autoatlanta.com/porsche-parts/hardparts.php?dir=986-97-04&section=202-05

 

Perhaps you can search the Bosch equivalent for those in your country.

Edited June 11, 2016 by Ahsai