Codes P0102, P1124, P1126

[BoxsterTaff]

I've just bought an ainnova 3100 diagnostic reader from amazon for $89.00 (which i thought was a bargain price) as I've been having a few issues with my 97' Boxster and wanted to become less dependant on taking her to the tech each time.

So I've recently had the pre cat O2 sensor replaced on the drivers side, but its still idling rough, so i plugged in the new meter and got the following codes:

P0102 - mass or volume air flow circuit low input

P1124 - O2S sensing range 1 cyl 1-3

P1126 - O2S Sensing range 1 cyl 4-6

I'm going to clean the MAF sensor first, and see if this then balances the O2 readings - my assumption being that if the MAF is giving bad readings it will result in the O2 sensors results not being what the comp thought they should be based on the MAF (false) readings?

Any suggestions guys.

[Loren]

P0102 Mass Air Flow Sensor - Below Lower Limit

Possible cause:

- Open circuit.

- Short circuit to ground

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

P1126 Oxygen Sensing Adaptation Area 1 (Cylinders 4 - 6) - Rich Threshold

Possible cause:

- Intake air system leaking.

- Fuel pressure too low.

- Volume supply of fuel pump too low.

- Fuel injectors fouled.

Your car is seeing too much air. You likely have an intake leak.

[BoxsterTaff]

Thanks Loren,

I have the engine open, and I can hear air 'leaking' from the area of the intake manifolds, so I'll keep looking for the leak - any suggestions on spotting it, or shoudl I just start to dismantle the intake system and find the crack/hole/bad seal? I assume the leak is down stream of the MAF which is making the mixture lean?

Now the MAF has me stumped, I will clean it anyway, but....... I'm a Civil Eng so once I get into electrics I am stumped!

How can I test for the open circuit or ground fault? These would be a worn cable i presume?

Thanks

Andy

Edited February 19, 2011 by BoxsterTaff

[BoxsterTaff]

Can anyone suggest ways to test for ground or an open circuit on the MAF with a multimeter?

[Loren]

Per the OBD II manual

Check wiring from MAF sensor to DME control module for continuity.

1. Remove connector of MAF sensor.

2. Connect special tool 9616 to wiring harness (DME control module connector).

3. Connect ohmmeter to special tool 9616, pin 17, and MAF sensor connector, pin 5.

Display: 0 - 5 ohms

If infinite ohms is displayed, check wiring harness for chafing and pinching damage.

Check wiring from MAF sensor to DME control module for short to ground.

1. Remove connector of MAF sensor.

2. Connect special tool 9616 to wiring harness (DME control module connector).

3. Connect ohmmeter to special tool 9616, pin 17, and to ground, pin 6.

Display: infinite ohms

If 0 - 5 ohms is displayed, check wiring for chafing and pinching damage.

[BoxsterTaff]

Thanks Loren, I've cleaned it, and checked the connections and cables visually, I don;t havr the special tool so will skip it. If the fault persits i'll pop in a new MAF once i've found the air intake leaks...........

[Loren]

Yes, fix the air leaks first -- air leaks can cause you to falsely suspect the MAF.

[BoxsterTaff]

The more you do the more you find!!

Decides as i was in the intake area looking for leaks to go ahead and replace the AOS as a precaution, car has never smoked other than on start up. So - I ran the engine to re-fill the coolant, see other post on that (coolant cap failure) and she started to smoke, not real bad but enough!

So i started to dimantle the Throttle body, and intakes, and this is what I found (aside from the fact that only 2 of the horizontal bolts attaching it to the intake manifold were there :censored: )

second picture is the tube between the intake manifolds (btw if you're taking it off, be careful as it has two vacuum pipes attached to the front of it)

I am going to take the manifolds off, clean them both and all the other air intake pipes engine side of the throttle body, clean the J-tube from the AOS, replace the AOS and then put it all back together.

I had the spark plugs changed when it was in with an indi 4 weeks ago (I guess they either looked ok or he didn't realize what the crud on them could have meant :censored: )

Any advise would be awesome, do you gys think I am on the right track here?

Andy

[BoxsterTaff]

I found it useful to use a tie-rap to hold the throttle plate open so i could clean it easily. I used CRC Lectra-Motive per Pedro's Garage advice.

[BoxsterTaff]

Ok, so after all that - no smoke :clapping:

:cursing: but its still running rough on idle and i can def hear a 'hissing' sound from somewhere near the top of the engine..... the vid link to you tube is the best i can do, if you listen, you can here the idle fluctuating, and a 'hissing' esp when the camera is back from the engine a bit. I checked all the air hoses etc, nothing looked loose, cracked or split. Any ideas? I'd really apreacite some expertise guys! Thanks

Been in the garage for 10 hours now......time to call it a day!

[BoxsterTaff]

Leaking Oil Filler Tube!

Ok, so I removed the filler tube at the joint below the AOS J tube, placed a Gator Aid bottle cap over the reming finnet tube, taped it with duct tape and hey presto.....hissing sound gone, engine idling like a sweet Prosche should!

So my question, would a leak in the Oil intake tube, I.e crankcase vacuum leak have caused my CEL codes? I also just fitted a new Bosch MAF.

[BoxsterTaff]

Well - first test run with the new MAF, new ICV, cleaned TB, new AOS and (temp) fix to the leaking air intake.

1) Idle is smooth cold and hot.

2) Temp ran slightly cooler - would a rich mixture cause the engine to run hotter - i guess it would, more gas and all?

3) Less of a 'gas' smell from the exhaust, so i guess its not thinking its running lean anymore?

Can any of the experts on here explian the connection between Crank-Case Vacuum leaks and the fuel air mixture / MAF issues?

FIngers crossied the dreaded CEL stays off!

[kbrandsma]

Leaking Oil Filler Tube!

Ok, so I removed the filler tube at the joint below the AOS J tube, placed a Gator Aid bottle cap over the reming finnet tube, taped it with duct tape and hey presto.....hissing sound gone, engine idling like a sweet Prosche should!

So my question, would a leak in the Oil intake tube, I.e crankcase vacuum leak have caused my CEL codes? I also just fitted a new Bosch MAF.

Very common to throw codes with cracked or leaking oil filler tube. It is best if replaced rather than taped. There are three tubes that connect from the trunk to the center front top of the enginge. The leak is usually between the 1st and 2nd joint, which is next to the AOS and under the air tubes and throttle body. Be careful if you attempt to remove and replace the 1st and 2nd tube because the 3rd tube is connected to the engine by a couple of thin plastic ears and they can break off. Ask me how I know:(

Here is a link to a recent Forum Discussion. PRESS HERE

Edited March 12, 2011 by kbrandsma

[BoxsterTaff]

Leaking Oil Filler Tube!

Ok, so I removed the filler tube at the joint below the AOS J tube, placed a Gator Aid bottle cap over the reming finnet tube, taped it with duct tape and hey presto.....hissing sound gone, engine idling like a sweet Prosche should!

So my question, would a leak in the Oil intake tube, I.e crankcase vacuum leak have caused my CEL codes? I also just fitted a new Bosch MAF.

Very common to throw codes with cracked or leaking oil filler tube. It is best if replaced rather than taped. There are three tubes that connect from the trunk to the center front top of the enginge. The leak is usually between the 1st and 2nd joint, which is next to the AOS and under the air tubes and throttle body. Be careful if you attempt to remove and replace the 1st and 2nd tube because the 3rd tube is connected to the engine by a couple of thin plastic ears and they can break off. Ask me how I know:(

Here is a link to a recent Forum Discussion. PRESS HERE

Thanks - I would not have linked the oil fller tube to this. Good to know its fairly common to get these codes due to this issue. I replaced the AOS etc, and I could hear a strong hissing, checked all the vacuum pipes and lintake for leaks with carb cleaner, but could not pin it down. I hear you on the lower oil filler tube ears, see this thread - mine was held on with only one bolt too - but solid with no cracks. I taped a 'cap' to the top of the lower tube, and hey-presto no leak so it must be in the middle tube. Oil filler cap seal looks good and idle didn't change when i opened the cap.

I have the middle tube section on order - looks like a PITA to install the upper joint though!