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Discussion Starter · #1 ·
Hi -

For several months I've been trying to nail down a few weird errors that lead to several codes...specifically:

40 CAT converting OBDII Error !!
Error frequency : 2
Logistic counter: 77
Engine speed 1520.00 rpm
Load signal 1.40 ms
Intake air temperature 52.50 degrees C
Fehler aufgetreten vor 4.70 h
Hexcode=28D20041FF43024D261C867108272C7D 0.00 [HEX]
min value fall below
axhaust relevant Error (after checkup MIL on)
Error present
Sporadic error
-------------------------------------------------------------
35 Lambda regulator-Adaption QL additiv OBDII Error !!
Error frequency : 4
Logistic counter: 40
Engine speed 680.00 rpm
Load signal 1.45 ms
Intake air temperature 40.50 degrees C
Fehler aufgetreten vor 3.10 h
Hexcode=23915142FF420428111D768108111D76 0.00 [HEX]
max value exceed
axhaust relevant Error (after checkup MIL on)
Error not present
Sporadic error
-------------------------------------------------------------
45 CAT converting Bank 2 OBDII Error !!
Error frequency : 1
Logistic counter: 77
Engine speed 1560.00 rpm
Load signal 2.20 ms
Intake air temperature 45.75 degrees C
Fehler aufgetreten vor 1.70 h
Hexcode=2D520041FF43014D272C7D8F08FEFEFE 0.00 [HEX]
min value fall below
axhaust relevant Error (after checkup MIL on)
Error present
Static error
=========================================================

I Believe I've now found part of the culprit, as all four heated O2 sensors are new and both Cats are new Magnaflows.

Putting the car--running--on INPA and getting the attached screen shot for a readout, it appears as though my "needed air i.s. controller" is way out of tolerance. At the time I took the screen shot, the "total air consumption HLM" was in the green, but much of the rest of the time connected, that reading was also way off the scale. As a test, I disconnected the MAF to see if the numbers changed...they did..both total air consumption and needed air i.s. controller actually went HIGHER. The car kept idling.

So...sorry for all the detail to get to the question, but....do both of those readings indicate a bad MAF? Am I reading the indications correctly? Not really sure what both of them mean.

Once the car clears it's "READY" state for sensors (still haven't figured out how many cycles that is), it seems to only be a matter of time before it first throws a "out of fuel trim--bank one" code, followed by both Catalyst Efficiency codes.

thanks
b52murph
 

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Do you mean 7000? Is this why my tach is pegged at max rpm as well..even though the car seems to be idling fine?
No. Your RPM reading in INPA says 700rpm...the MAF reading is pegged see attached. MAF reading that high would be at really high rpm. I presume you were idling with your AC on when this reading was taken?

Do you have other errors on the car DME, IKE, etc? like read from the IKE (instrument cluster) and report back
 

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Discussion Starter · #5 ·
No. Your RPM reading in INPA says 700rpm...the MAF reading is pegged see attached. MAF reading that high would be at really high rpm. I presume you were idling with your AC on when this reading was taken?

Do you have other errors on the car DME, IKE, etc? like read from the IKE (instrument cluster) and report back
Yes...I was idling with the A/C on at the time. And many many thanks. The weird tach problem (gauge pegged at max with no other indications in INPA) was cleared when I did an all codes recode using NCS expert. Figured I'd try it as last resort; not sure why the gauge went haywire (both KOMBI and DME readings in INPA indicated normal idle)...but that "problem" is corrected now.

After all is said and done, this INPA screen for the DME still indcates the same...mainly that the "total air consumption--HLM" is often off the scale at idle (hot afternoon here, probably 85deg F).

Interestingly, disconnecting the MAF throws a Code 115, but with the MAF connected, no codes are thrown at normal idle. Only after running does it throw the P1175, followed shortly by the P0420/P0430.

Sounds like the "root cause" is a almost-shot MAF, yes?

thanks much
b52murph
 

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Def an oddity with the MAF being pegged. What happens when you unplug the MAF?

Your other codes sure appear to be related to bad intake manifold gaskets or CCV, from experience. But I'm not use to seeing the MAF get pegged unless its having a fault of its own.
 

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Discussion Starter · #8 ·
Def an oddity with the MAF being pegged. What happens when you unplug the MAF?

Your other codes sure appear to be related to bad intake manifold gaskets or CCV, from experience. But I'm not use to seeing the MAF get pegged unless its having a fault of its own.
When I unplug the MAF, the numbers go even higher!

The CCV is also new as is the hose connections. Already put over $7K into this car in parts over the last 8-10 months (most work done myself!)...

Havent done anything with the manifold gaskets.
 

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can you post the reading from the lambda sensors? pre-cat o2 sensors as well as the post-cat sensors. I think a MAF issue usually results in a rich condition...and an intake leak after the MAF would cause a lean condition. I would try to clean the MAF for one thing. But 2 of your codes point to bad cats or bad post cat sensors. How new are your cats? give them a tap and see if you hear rattling.

post-cat sensors should be around 0.45V i believe but do post the INPA readings.

You may have 2 seperate things going on here.

I would...

1.) try to clean the MAF and see if this help.

2.) test for intake leaks after the MAF...one good way is to detatch filter from MAF and set up a pump or compressor in front to pressurize. I have a short plumber attachment I use with a barb fitting on it. Attach a pressure gauge to the manifold. It should be a slow release. If you spray soapy water on the intake it will bubble at a leak. pay attention to joints, the helmholtz resonator under the elbow, connection to throttle body, ring behind TB, gasket on the plate behind the TB, and all vacuum hoses. don't go over 10psi though.

3.) make sure the cats don't rattle
 

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Discussion Starter · #12 ·
can you post the reading from the lambda sensors? pre-cat o2 sensors as well as the post-cat sensors. I think a MAF issue usually results in a rich condition...and an intake leak after the MAF would cause a lean condition. I would try to clean the MAF for one thing. But 2 of your codes point to bad cats or bad post cat sensors. How new are your cats? give them a tap and see if you hear rattling.

post-cat sensors should be around 0.45V i believe but do post the INPA readings.

You may have 2 seperate things going on here.

I would...

1.) try to clean the MAF and see if this help.

2.) test for intake leaks after the MAF...one good way is to detatch filter from MAF and set up a pump or compressor in front to pressurize. I have a short plumber attachment I use with a barb fitting on it. Attach a pressure gauge to the manifold. It should be a slow release. If you spray soapy water on the intake it will bubble at a leak. pay attention to joints, the helmholtz resonator under the elbow, connection to throttle body, ring behind TB, gasket on the plate behind the TB, and all vacuum hoses. don't go over 10psi though.

3.) make sure the cats don't rattle
I've attached all three monitor screens from INPA.

The cats are brand new, direct-fit, magnaflows, installed a month ago. Total cost to install including the parts was almost $2K! The previous owner had welded in cheap, after-market cats such that the exhaust system was welded end-to-end. Took a professional with a torch more than 8 hours to get the new ones installed--to include new exhaust manifolds.

I cleaned the heck out of the MAF today using the CFC MAF cleaner. The screen shots you see attached are after the cleaning--basically, no change. O2 sensors seem to be right around .45v. All 4 O2 sensors were replaced in January & February this year, OEM Bosch.

I'll try your test in #2 to see if I have a leak up there.

Again, many thanks!

b52murph
 

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Discussion Starter · #13 ·
Had a chance today to grab several screen shots of the monitors while driving at slow-ish speeds (25-35mph).

Key take away--the "total air consumption" numbers only went HIGHER as RPMs and speed increased...still not seeing any leaks in the intake and throttle body, so I guess a new MAF is in order?

The Lambda sensors all stayed within normal limits at a variety of speeds....
 

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Well...I tested a new MAF today (remf'd). The readings were EXACTLY the same in INPA....the "total air consumption" dropped to within range of the scale once I turned the A/C off on both MAFs. Might had been a flaw in my previous tests to take the readings with the A/C on during very hot days (90+ deg F).

So, back to the drawing board. Just a matter until my P1175, P0420 and P0430 return, I'm afraid....
 

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have you cleared adaptations? everytime you add a new sensor you should clear them and let the car relearn the adaptation. Your adaptation value sort of tells me you did not do this as it seems pretty high. do these you go to "error" and on the right you click "apaptations". Values of +13 seems funny to me.


These cars tend to have issues with non-OEM cats...you may want to try to pick up some de-foulers that pull the post cat o2 sensors out of the exhaust pipe...clear codes and see if they return. This may be a way to test the cats.
 

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Discussion Starter · #16 · (Edited)
have you cleared adaptations? every time you add a new sensor you should clear them and let the car relearn the adaptation. Your adaptation value sort of tells me you did not do this as it seems pretty high. do these you go to "error" and on the right you click "adaptations". Values of +13 seems funny to me.

These cars tend to have issues with non-OEM cats...you may want to try to pick up some de-foulers that pull the post cat o2 sensors out of the exhaust pipe...clear codes and see if they return. This may be a way to test the cats.
Well...the issue may be non-related to the MAF after all. Looking at the back of my intake today, I realized that the new CCV I had installed in January had TWO vacuum connections at the top as well as the big connector at the bottom. I had reconnected the passenger-side vacuum line; however the second connection was just open...not capped....I cannot remember if the original CCV I took off back then had a second connector with a cap.

Obviously, there was open suction coming through the open (driver's side) vacuum port. I capped this off earlier today, and with plenty of driving, have not had any codes return...either P1174/1175 or P0420/P0430.

So...assuming that was the real problem...can anybody tell me:

1) Is there supposed to be TWO vacuum hoses connected to the top of the CCV? I've seen a pic of a `99 740iL with both ports connected to hoses; however, I don't think I missed connecting a hose anywhere...nothing I can find. Perhaps the second vacuum port was used in a later-than-1997 application?

2) If the second port on the CCV was accidentally left open months ago, would that be causing fuel trim and O2 sensor problems?

many thanks
 

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On my 2000 540i one vacuum line goes to the secondary air pump vacuum control valve. http://www.realoem.com/bmw/showparts.do?model=DN63&mospid=47588&btnr=11_2287&hg=11&fg=45

I'm not sure where the other one goes. I can't trace the line past the box under the left cabin air filter, without some dis-assembly. It may be the line that goes to the fuel pressure regulator. Number 12 on this diagram. http://www.realoem.com/bmw/showparts.do?model=DN63&mospid=47588&btnr=13_0811&hg=13&fg=10

You would not have this second vacuum line if you do not have this pressure regulator setup.
 

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Had a chance today to grab several screen shots of the monitors while driving at slow-ish speeds (25-35mph).

Key take away--the "total air consumption" numbers only went HIGHER as RPMs and speed increased...still not seeing any leaks in the intake and throttle body, so I guess a new MAF is in order?

The Lambda sensors all stayed within normal limits at a variety of speeds....
Hi b52murph, do you know to test MAF on a E60 M54?

I found the following sections in the INPA to read the air flow, not sure what it means or does.

From the different pictures and my testing with INPA what I can see is below;
MAF Sensor Voltage at ignition (engine off) is 0.41V with 4kg/h and Air mass = 1.1 g/sec
MAF Sensor Voltage at engine on is 1.4V which comes down on 1.2V with 13kg/h and Air mass = 3.4 g/sec

From the reading above, and the images, can someone help me to diagnose how to test if the MAF sensor is functioning fine.
 

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