How to code your BMW MAF, recoding your BMW air flow meter.
Hot-film air mass meter (HFM)
E38, E39, E46 / with M47, M57
This details how to code your car to accept the newer MAFs that replaced the now obsolete MAF that was present on the e46 320d's launch up till 2001 September. Intermittent boost problems can be down to an uncoded new part number MAF.
This requires access to DIS and for you to understand how to use it. Neither I nor the forum will be held responsible for any damage you may do to your ECU if something goes wrong!
Situation: 1. In the BMW dealer organisation, the hot-film air mass meter is often replaced unnecessarily on vehicles with M47 or M57 engines.
The diagnosis procedures for finding the cause of a customer's claim regarding the response of the engine and the vehicle's performance are often only used if the replacement of the HFM has not resulted in the complaint being rectified.
2. Since November 2001, the BMW Parts Service has only supplied the air mass meter version fitted to vehicles with M57 engine from January 2001 and on vehicles with M47 engine from September 2001. This means a revised procedure for retrofitting.
Affected vehicles: E38, E39, E46 with M47 or M57 engine.
Procedure: In case of customer complaint, the DDE fault memory should first be read.
[Note] Hot-film air mass meters sent in through warranty/goodwill can only be processed in conjunction with the diagnosis report. In countries where return is not obligatory, the diagnosis report should be filed in the vehicle records for reliable auditing.
Proceed as follows if the fault memory entries or the nature of the complaint indicate an HFM malfunction:
A. M47 engine with DDE 3.0
With the DIS tester, work through test module "air mass meter".
The test module can be found in the function selection on the DIS tester under => Complete vehicle => Drive => DDE 3.0 engine management => Air supply => Air mass meter
The air mass meter must only be replaced if the nominal values specified in the test module "air mass meter" are not achieved and an instruction is given to replace the HFM.
A. M57 engine with DDE 4.0
With the DIS tester, work through test module "air-mass system test".
The test module can be found in the function selection on the DIS tester under => Complete vehicle => Drive => DDE 4.0 engine management => Air-mass system test
In the air-mass system test, the cause of the fault in the air-mass system is isolated clearly to the defective component group and the test module for the component group concerned is automatically drawn into the testing schedule for working through.
The HFM is then only to be replaced if an appropriate instruction to replace the HFM is given in the test module "Air-mass system test".
The following applies to both engines:
On no account should just the sensor element in the housing be converted. The position of the sensor element is assigned to the housing and cannot be set in service!
Before programming, it must be noted that programming may abort on the E38 and E39 under the following conditions:
1. Programming abort on vehicles with DSC III (E38 and E39 from date of manufacture September 1998 to December 1999)
2. Programming abort on vehicles without DSC III
The cause of a program abort could be the ignition being switched off during programming, by the connection between DIS/MoDiC III and the control unit being broken or by the system voltage dropping below approx. 9 volts.
The functionality of the control units with FLASH technology are designed such that programming can be repeated following a program abort.
In case 1: During the programming procedure, the DSC III control unit interferes with telegram traffic between the control unit being programmed and the DIS/MoDiC III.
In case 2: The control unit being programmed refuses to communicate with the DIS/MoDiC III because of interference on the diagnosis cable.
Always connect up a battery charger before programming as a measure against a programming abort. Never connect or disconnect the charger during programming.
The vehicle voltage must not drop below approx. 9 volts during programming.
In case 1: Programming can only be correctly performed if the DSC III control unit is rendered free of current throughout programming. This is done by pulling the following fuse:
E38: fuse 17 (engine compartment)
E39: fuse 31 (glove compartment)
In case 2: If programming is aborted and the situation is not described under 1 above, the control unit should be disconnected for approx. 1 minute. After this, reconnect, switch on the ignition and perform programming again.
The most recent version of the air mass meter (part number 13 62 7 787 076) can be recognised by the protective grille for deflecting particles of dirt and moisture (see illustration 1).
Illustration 1: Most recent version of air mass meter.
This version can be retrofitted on all E38, E39 and E46 vehicles with M57 engine and on all E39 and E46 vehicles with M47 engine, providing the current DDE data status is programmed with the installation.
[Note] The part number of the programmed control unit must be entered manually.
[Note] If programming is not performed, the DDE control unit will misinterpret the air-mass signals, affecting the engine's power output and exhaust emission characteristics.
When reprogramming the DDE control unit, proceed in the same way as when renewing the control unit, even though the existing control unit is not being replaced:
1. Identify and print out the DDE control unit using => Diagnosis => Control unit functions.
Identification of the control unit is purely for reading off the part number of the basic control unit and of the control unit to be programmed.
2. The control unit can now be reprogrammed using => Programming => DDE programming => Replace control unit.
3. The following prompt appears in the DIS tester: => "First determine basic control unit".
4. Answer the question =>"Is the defective control unit still installed in the vehicle?" with "No".
5. Enter the part number of the basic control unit from the control unit identification.
6. Enter vehicle identification number.
7. Enter the new part number of programmed control unit.
This part number can be found in various enclosures according to model series, engine and transmission versions (please refer to Enclosures 1 to 9):
Find the old part number of the programmed control unit read out from the control unit identification in the appropriate table (column "Old part number") and read off the new part number of the programmed control unit (column "New part number").
8. Perform automatic programming and then a DDE/EWS calibration.
9. Perform " DDE control unit identification" again and check whether the new part number of the programmed control unit has been taken over.
Enclosure 1: E46, M47 with manual transmission
Enclosure 2: E46, M47 with automatic transmission
Enclosure 3: E39, M47
Enclosure 4: E46, M57 with manual transmission
Enclosure 5: E46, M57 with automatic transmission
Enclosure 6: E39, M57 D25
Enclosure 7: E39, M57 D30 with manual transmission
Enclosure 8: E39, M57 D30 with automatic transmission
Enclosure 9: E38, M57
Description: HFM for M47 and M57 engines
Part number: 13 62 7 787 076