I have a 2002 745i. It is in really good shape.
Yesterday I ran a scan and got the following codes.

1. 272A multiplicative mixture adaptation-bank 1 control limit reached
2. 272B multiplicative mixture bank 2 control reached
3. 272D additive mixture adaptation bank 2 control limit reached.

Does anyone know what these are telling me?

Thanks....

You need New O2 sensors ...

 

Should I replace all 02 sensors? It appears that there are 4 of them.

Thanks again.

 

Thanks to paper for the reply. I changed the 02 sensors and after a week I have not experienced the problem!

Next challenge: My ac system works fine except that after driving with the ac on for more than 15 minutes, it starts to go to what feels like vent, If I turn off the ac and wait 10 minutes and turn it back on, it comes back up cold. It acts as though a sensor is detecting low freon or that something is not working properly. Any thoughts?

 

I would have the Freon level checked 1st ( it might be low ) .

 

Paper, I am scheduled to get my Freon checked on Monday, we will see if that solves the problem.

On the initial issue with my codes. I changed all the O2 sensors and drove two tanks of gas with sea foam.
I cleared the codes and yesterday the Multiplicative code for bank one and two returned. Any thoughts?
Thanks!

 

Did you change all 4 o2 Sensors ???
Only other thing I can think of is bad Katz
Could have been the Seafoam in the system also .
try driving for a couple weeks to clear it out & then clear the codes ...

 

Ok, Paper. I may the trip. About 1000 miles round trip. It ran great the first half. When I got to SC it started to miss in idle.
It still ran good, but had a bad miss/bump when idling.
Drove back and it ran good, except for when I was idling in drive. The miss shook the car.
When I got back, I ran a scan. I got:
271a and 272a - multiplicative mixture adaptation control limit reached on bank 1 and 2.
I also got a bump reading on cylinder 2 and 7 of .09 and .04. The others were all in range.
The only other time that I had a miss like this was when one of the igniters was bad. Could this be
what's going wrong now? Thanks.

Also, I had the ac system drained and refilled. I had the same problem. After about 30 minutes of running
the ac, it would start to warm. If I turned the ac button off and then turned it back on after a few minutes,
it would come back strong. Your thoughts? And Thanks.

 

Ok, Paper. I may the trip. About 1000 miles round trip. It ran great the first half. When I got to SC it started to miss in idle.
It still ran good, but had a bad miss/bump when idling.
Drove back and it ran good, except for when I was idling in drive. The miss shook the car.
When I got back, I ran a scan. I got:
271a and 272a - multiplicative mixture adaptation control limit reached on bank 1 and 2.
I also got a bump reading on cylinder 2 and 7 of .09 and .04. The others were all in range.
The only other time that I had a miss like this was when one of the igniters was bad. Could this be
what's going wrong now? Thanks.

Also, I had the ac system drained and refilled. I had the same problem. After about 30 minutes of running
the ac, it would start to warm. If I turned the ac button off and then turned it back on after a few minutes,
it would come back strong. Your thoughts? And Thanks.

IM VERY SORRY I TOOK SO LONG TO REPLY !!!
Yes most definitely could be Igniters fouling out , I would try some Fuel Injection cleaner ( I myself put in 4 bottles of cleaner ) than fill the tank .

Im going to tell you something I do once every 6 months BUT Do at your own risk . I take No Responsibility !!!
I drive the car til empty , than I put in 10 gallons of high octane Racing fuel ( needs to be purchased at a race shop ) .
I than jump on the Freeway & punch it , Usually it will let out a big puff of black smoke ( Since it will be your 1st time )
My car lets out a very light Gray color now since I been doing it for years . After this I drive til empty , than use 4 bottles of Lucas injector cleaner & fill tank . Car has never had any issues .

As for your A/c problem , check the
Blower Motor & Blower Motor Resistor
behind the radio .
links to parts

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Paper, I will give the Lucas injector cleaner a try. Thanks.
Is there any significance to the bump readings on cylinders 2 and 7?

You are suggesting that the problem with my AC is possibly the blower motor resister? Right?

 

Can anyone help me with interpreting the following:
I ran a scan. I got:
271a and 272a - multiplicative mixture adaptation control limit reached on bank 1 and 2.
I also got a bump reading on cylinder 2 and 7 of .09 and .04. The others were all in range.
Help!

 

My 745i still has a miss at idle when the outside temperature is above 70 degrees and will struggle to start after 3 or 4 stops and starts. I have had the o2 sensors replaced; the engine checked for vacuum leaks, valve cover gaskets replace, fuel pump and spark plugs replaced. The work was done by a euro car tech and by BMW service. None of these things corrected the problem. I can drive all winter without an issue and as soon as the weather warms up, the
problem returns.
Otherwise the car runs great; handles great and has been well cared for. The parking brake motor is failing, so I get an abs light from that. When I scan the codes, I get a multiplicative mixture code.
Does anyone have any thoughts about this or suggestions as to who I should talk to. I have given up on the dealership and most techs here won't work on it, stating that it is too complicated to solve its issues.
Marv in tidewater, Va.

Thanks

 

Sorry to hear your still having issue's . Only other thing I can think of is your fuel
pump , But you said you replaced it . I see you replaced Spark plugs , What about
your Coil Packs ? Or Maybe even your IVM module ( that going bad would cause the start issues )
as for your Parking brake , make sure you use the ===
Metal Parking Brake Gear Actuator

link

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Paper, Thanks for your reply. I did replace the IVM module last year around the time that I replaced the O2
sensors.
I had hoped that whatever the problem was that it would completely fail and could then be diagnosed, but it
hasn't in almost 3 years...really puzzling. But it makes the car unusable during the summer, because whatever
the issue is, it is brought on by heat.
Thanks for the gear actuator kit. I will order that and at least eliminate the abs light.
Such a great vehicle, to not be able to solve this issue.
Talk soon.
Marv in tidewater, Va

 

Paper, is there just one gear actuator for the car? Thanks.

 

yes just 1 actuator .
If I recall correctly I remember another member having issue's in the summer with starting .
He ended up changing his Power module in the trunk & his IVM Module & it was fixed .

Just a side note I have replaced the IVM module & the New Module went bad soon after .

 

Paper, do you have links for the ivm and power modules?

 

You should buy those New from the Dealer or FCP Euro

 

Ok, thanks. I will look them up tomorrow
do you have part numbers?.

 

And what was the test to determine that the IVM module was bad?

 

as well as the power module (expensive)

 

ok, Thanks, but what was the test to determine that the power module(expensive) and IVM modules were bad?

 

Where is the best place to get a fuel pump for my 2002 745i?
Thanks.