Fault Code 227/228 (12 12 97)

FAULT CODE 227/228

TECHNICAL SERVICE BULLETIN

SUBJECT

Fault Code 227/228

SITUATION

"Check Engine" lamp is illuminated and the following faults are set in the Engine Control Module (DME):

1. FC 227 - Mixture deviation, cylinder 1-3 and/or
2. FC 228 - Mixture deviation, cylinder 4-6

CORRECTION

1. Check if the correct Air Mass Meter P/N 13 62 1 703 275 is installed. If the wrong Air Mass Meter is installed it will need to be replaced along with the Suction Silencer.
   NOTE: The rubber boot may not need to be replaced as it contains a rubber "downsizing" ring used for installing the smaller Air Mass Meter on other models. Remove the inner rubber ring from the rubber boot in order to install the larger Air Mass Meter.

   As an example:  If parts from a smaller engine (2.01) are installed in a 2.81, not enough air will be brought into the engine under certain driving conditions. A reduction in air flow can be noticed by checking the adaptation values, which in this case may reflect a "Multiplicative mixture adaptation" of approximately -6% to -8%.

2. If the correct air mass meter is installed check the adaptation values located in the DME diagnostic status section. The adaptation values can provide further insight as to what may have caused the fault to set. Once a certain adaptation threshold value is exceeded the system can no longer make the necessary correction and a fault is logged, as explained below.

   After repair(s) are made pertaining to an adaptation related fault, the adaptation values should be cleared. The vehicle can then be driven under various load conditions and readapted. By rechecking the adaptation values an indication as to the success of the repair can be obtained.

Multiplicative mixture adaptation (Part Load) 

Adaptation occurs while vehicle is under load.

• If the value is greater than 6% there may be an unmetered air leak, not enough fuel being supplied to the system or an erroneous signal from the air mass meter. The oxygen sensor measures a LEAN signal which causes the DME to compensate for the problem by trying to make the mixture RICH.
• If the value is less than -7% there may be an air restriction, too much fuel in the system or an erroneous signal from the air mass meter. The oxygen sensor signal measures a RICH signal which causes the DME to compensate for the problem by making the mixture LEAN.

Additive mixture adaptation (Idle) 

Adaptation occurs while vehicle is at idle

• If the value is greater than 0.2 ms there is an unmetered air leak, not enough fuel being supplied to the system or an erroneous signal from the air mass meter. The oxygen sensor signal measures a LEAN signal which causes the DME to compensate for the problem by making the mixture RICH.
• If the value is less than -0.2 ms there is an air restriction, too much fuel is being supplied to the system or an erroneous signal from the air mass meter. The oxygen sensor signal measures a RICH signal which causes the DME to compensate for the problem by making the mixture LEAN.

PARTS INFORMATION

Part Number	Description	Qty.
13 62 1 703 275	Air Mass Meter	1
13 71 1 740 140	Suction Silencer (328i)	1
13 71 1 740 067	Suction Silencer (528i)	1

WARRANTY INFORMATION

Parts and labor will be reimbursable under the terms of the applicable BMW Emissions or Limited New Vehicle Warranty.

Removing and installing or replacing Air Mass Meter 

Defect Code	Labor Operation	Labor Allowance
13 72 01 32 00	13 62 560	1 FRU

Replacing complete Air Cleaner 

Defect Code	Labor Operation	Labor Allowance
13 72 01 32 00	13 71 001	4 FRU