How JustAnswer Works:
  • Ask an Expert
    Experts are full of valuable knowledge and are ready to help with any question. Credentials confirmed by a Fortune 500 verification firm.
  • Get a Professional Answer
    Via email, text message, or notification as you wait on our site.
    Ask follow up questions if you need to.
  • 100% Satisfaction Guarantee
    Rate the answer you receive.
Ask sprinkles08 Your Own Question
sprinkles08
sprinkles08, ASE Certified Technician
Category: BMW
Satisfied Customers: 21599
Experience:  ASE Master and Advanced level certified. Factory trained with 15 years dealership experience
9825021
Type Your BMW Question Here...
sprinkles08 is online now
A new question is answered every 9 seconds

I have an 07 mini r56 with an 2b5c mass air plausibility

Customer Question

I have an 07 mini r56 with an 2b5c mass air plausibility code
I smoke tested the intake found no leaks
The customer complains of rough idle and it has had 5 mass airflow meters replaced each purchased from mini
At a stand still since shopkey data on this is limited
Submitted: 8 months ago.
Category: BMW
Expert:  sprinkles08 replied 8 months ago.

Hello and welcome to JustAnswer!

This is a performance type code that sets when the mass airflow signal isn't valid for operating conditions. This sets when there isn't enough airflow seen. Possible causes are the sensor, it's wiring, or a leak allowing air into the engine that isn't being measured.

If the sensor has been replaced with a factory part five times then there is little question that you can rule it out.

Has the sensor wiring been tested?

Will the engine run if cardboard is introduced over the throttle body?

Customer: replied 8 months ago.
Wiring has been tested
Had 12v
Dme ground
The 5v reference was there
Did not try cardboard to the intake but intake system was smoke tested with no leaks
Expert:  sprinkles08 replied 8 months ago.

There isn't a way to seal an intake to properly pressurize it with smoke because some intake valves are always open, so I don't put much faith in 3 PSI of smoke to find a vacuum leak. Try the cardboard and see if it will die or continue to run.

Customer: replied 8 months ago.
It died after cardboard was introduced
Expert:  sprinkles08 replied 8 months ago.

What is the MAF grams per second with the key on engine off and with the engine idling when the code is active?

Customer: replied 8 months ago.
2.40 koeo
10.4 koer but jumps around
Expert:  sprinkles08 replied 8 months ago.

If it's showing airflow without the engine running then you have a wiring or sensor issue, it should be zero without air moving across the sensor.

Customer: replied 8 months ago.
you are right but
I have
12v
Dme ground
5v reference and have voltage return
Sensor is new purchased from mini
Expert:  sprinkles08 replied 8 months ago.

Something has been lost in testing, the sensor is bad or the failure is internal in the ECM (unlikely). Either the sensor is inaccurate, there is a wiring issue altering it's signal, or the ECM is interpreting the signal voltage incorrectly.

Customer: replied 8 months ago.
I'll do some more checking and get back to u
Expert:  sprinkles08 replied 8 months ago.

Ok.