SBT Enclosure: E46 ...  - EKP control unit

Installation location

  • E46 saloon/coupé: on the right-hand side of the luggage compartment on the wheel housing extension
  • E46 touring: on the base plate in the luggage compartment between the rear seat on the right and the luggage compartment recess
  • E60, E61: in the luggage compartment on the right-hand side next to the suspension strut dome
  • E63, E64: on the base plate under the rear seat
  • E87, E90, E91: in the vehicle interior on the right next to the rear-seat backrest

There are 2 versions of the EKP control unit:

  • EKP control unit with a total of 8 pins (until 03/04)
  • EKP control unit with a total of 20 pins (from 03/04)

From 03/04, only the control unit with 20 connector pins will be installed during replacement (exception: E46). The E87 has the new EKP control unit from start of series production.

Construction

EKP control unit for E46, E60, E61 (until 03/04)

The EKP control unit installed up to 03/2004 has 8 pins.

- Pin assignment on E46

Pin assignment for connector X13663, 6-pin
Pin Type Explanation
 

E = Input

E/A = Input and output

M = Earth

V = Supply

For current specifications regarding pin assignment, please refer to BMW diagnosis system

1 M Earth for EKP control unit
2 V Terminal 30, power supply
3 E/A Local CAN Low
4 E/A Local CAN High
5 E Wake-up wire for EKP control unit (terminal 15)
6 E/A K-bus

 

Pin assignment for connector X18203, 2-pin
Pin Type Explanation
 

A = Output

For current specifications regarding pin assignment, please refer to BMW diagnosis system

1 A Current supply, positive lead for electric fuel pump
2 A Current supply, earth cable for electric fuel pump


- Pin assignment on
E60 and E61 (up to 03/04):

Pin assignment for connector X13663, 6-pin
Pin Type Explanation
 

E = Input

E/A = Input and output

M = Earth

V = Supply

For current specifications regarding pin assignment, please refer to BMW diagnosis system

1 M Earth for EKP control unit
2 V Terminal 30, power supply
3 E/A PT-CAN Low
4 E/A PT-CAN High
5 E Wake-up wire for EKP control unit (terminal 15)
6 --- ---

 

Pin assignment for connector X18203, 2-pin
Pin Type Explanation
 

A = Output

For current specifications regarding pin assignment, please refer to BMW diagnosis system

1 A Current supply, positive lead for electric fuel pump
2 A Current supply, earth cable for electric fuel pump


EKP control unit E60, E61, E63, E64, E87, E90, E91 (from 03/04)

The EKP control unit installed from 03/2004 has 20 pins.


- Pin assignment on E60, E61, E63, E64, E87, E90, E91 (from 03/04):

Pin assignment for connector X13663, 16-pin
Pin Type Explanation
 

E = Input

E/A = Input and output

M = Earth

V = Supply

For current specifications regarding pin assignment, please refer to BMW diagnosis system

1 V Terminal 30, power supply
2 M Terminal 31, earth for EKP control unit
3 --- ---
4 --- ---
5 --- ---
6 --- ---
7 --- ---
8 --- ---
9 E/A PT-CAN High
10 --- ---
11 --- ---
12 --- ---
13 E Wake-up wire for EKP control unit (terminal 15)
14 --- ---
15 --- ---
16 E/A PT-CAN Low

 

Pin assignment for connector X3507, 4-pin
Pin Type Explanation
 

A = Output

For current specifications regarding pin assignment, please refer to BMW diagnosis system

1 -- ---
2 A Current supply, earth cable for electric fuel pump
3 --- ---
4 A Current supply, positive lead for electric fuel pump


How it works

Fuel requirement mappings are stored in the EKP control unit.
The fuel requirement mappings are encoded for each specific engine and model.

The EKP control unit uses the mappings as the basis on which to calculate the total amount of fuel to be delivered from the following reference variables:

  • Amount of fuel required by the engine (request from the DME control unit or DDE control unit)
  • Amount of fuel needed to lubricate the high-pressure pump in the diesel fuel system (mapping in the EKP control unit).

This results in a pulse-width modulated output voltage from the EKP control unit. The output voltage of the EKP control unit is the supply voltage for the electric fuel pump. The EKP control unit controls the speed of the electric fuel pump via the supply voltage. The EKP control unit controls the speed by comparing the actual speed with the specification.

The current speed of the electric fuel pump is calculated as follows:
The EKP control unit sends the current supply to the fuel pump (pulse-width modulated). This voltage is absorbed as a specific ripple due to the individual armature windings of the rotating electric motor. The ripple corresponds with the number of segments in the commutator (= corresponds with the number of armature windings in the electric motor).
The number of waves produced per revolution is equal to the number of existing commutator segments.

This means that the EKP control unit can employ a patented procedure (= “Ripple Counter”) as the basis for calculating the actual speed of the fuel pump using power consumption ripple.

 

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