Model And Production Date: E46 From 6/00 E39, E52, E53 From 9/00
For model year 2001 the E39, E46 and E53 will eliminate the 20 pin diagnostic connector from the engine compartment. The 16 pin OBD II connector located inside the vehicle will be the only diagnosis port.
The E38 and Z3 will continue to use the 20 pin connector until the end of production.
The 16 pin OBD II connector has been in all BMWs since 1996 to comply with OBD regulations requiring a standardized diagnostic port.
Previously before 2001, only emissions relevant data could be extracted from the OBD II connector because it did not provide access to TXD (D-bus).
The TXD line is connected to pin 8 of the OBD II connector on vehicles without the 20 pin diagnostic connector.
The cap to the OBD II connector contains a bridge that links KL 30 to TXD and TXD II. This is to protect the diagnostic circuit integrity and prevent erroneous faults from being logged.
The OBD II connector is located in the driver's footwell to the left of the steering column for E39, E46 and E53 vehicles.
Special tool 61 4 300 is used to connect to the 20 pin diagnostic lead of the DIS until the introduction of the DISplus.