Engine Control Module: Description and Operation
EMS2000 Control Module
The EMS2000 Control Unit is the center of the engine management system. It receives and processes all inputs and issues corresponding control commands.
The EMS2000 control unit is located on the left hand side compartment of the battery box (viewed from the drivers seat) next to the engine bay fuse box, on the MINI COOPER. On the MINI COOPER S it is located in a similar position to the left of the engine bay fuse box, mounted in a side compartment of the air box.
In addition to engine controls it has direct control over the following systems:
- Drive By Wire (DBW) throttle control.
- Automatic Transmission (ECVT).
- Cruise control.
- Air conditioning clutch relay.
- Cooling fan relays.
The EMS2000 also has an interface with the following systems:
- Air Conditioning (IHKS/IHKA).
- Automatic Stability Control (ASC).
- Dynamic Stability Control (DSC).
- Immobilization (EWS).
The EMS2000 connector is a single moulding split into two housings.
- Engine Housing - 81 Pin
Pins 1-5 : load terminals
Pins 6-81 : signal terminals
- Vehicle Housing - 40 Pin
Pins 114-121 : load terminals
Pins 82-113 : signal terminals
EMS2000 receives its operating power from the battery through the Main Relay and Ignition Switch.
System Inputs
Ignition Switch
When the ignition is switched on KL15 (F34) supplies wake up voltage to the EMS2000. The Main Relay is energized as long as KL15 is supplied.
Power Supplies
KL30 is supplied through a fuse (F01) to provide memory. KL30 (F02) as provided by the Main Relay supplies operating power to the EMS2000.
Battery Voltage - KL 30
B+ is the main supply of operating voltage to the EMS2000. Battery Voltage is monitored by the EMS2000 for fluctuations. The EMS2000 will adjust the output functions to compensate for a lower (6v) and higher (14v) voltage value. Based on the available battery voltage the EMS2000 will adjust:
- Fuel injection pulse width
- Ignition system dwell
Main Relay:
The Main Relay provides power for the EMS2000 and other system components. It has an additional function of protecting system components from reverse battery polarity. (Main Relay will not energize with reverse polarity.) When the ignition switch is placed in the KL15 or KL50 positions, Fuse 34 is provided with power. Fuse 34 supplies the wake up or on signal to the EMS2000. Upon receipt of the "ON" signal EMS2000 supplies a ground signal from Pin 97 to the Main Relay. The ground signal energizes the Main Relay, supplying operating power to the following fuses:
- F02 - EMS2000, Fuel injectors, Crankshaft sensor, Ignition coils.
- F03 - Camshaft sensor, 02 Heaters, Engine Cooling Fan, A/C Compressor Relay, Purge System.
- F04 - Automatic Transmission controls.
- F05 - Engine Coolant Fan.
The Main Relay supplies power to the following components:
- EMS2000
- LDP
- O2 Heaters
- Fuel Injectors
- Auxiliary Fan
- Crankshaft Sensor
- Camshaft Sensor
- Ignition Coils
- ECVT/GIU
Main Relay Failure Symptoms
An open circuit in the Main Relay will result in no voltage to the EMS2000 and the other components as supplied by the Main Relay.
A permanently engaged Main Relay will result in an excessive closed current draw and will lead to a dead battery.
Main Relay activation is monitored by the EMS2000. Faults will be set if the main relay is energized and power is not received by the EMS2000.
Main Relay Testing
- Check Voltage Supply At Battery.
- Test for Voltage at Fuse 34 (With key on).
- Check Voltage at KL 30 of Main Relay.
- Check operation of Relay (Using relay adapter).
- Ground signal from EMS2000.
- Voltage Drops across Relay (Relay Energized and Not Energized).
- Perform TEST PLAN on Power Supply.
Special Tools
When testing the power supply of the EMS2000, the DISplus multimeter function or a hand held multimeter may be used. It is best to make the checks at the EMS2000 connection as this method tests the wiring harness. The correct V-Adapter Cables must be used to ensure the pin connectors and the harness will not be damaged. V-Adapter Cables for the EMS2000 are:
- 40 Pin V-Adapter Cable P/N 12 7 240
- 81 Pin V-Adapter Cable P/N 12 7 250
- Breakout Box (BOB) P/N 61 4 390
- Breakout box (BOB) P/N 61 4 380
When installing the BOB and V-Adapter Cables to the EMS2000 make sure the ignition has been switched off for at least 5 minutes or remove the Main Relay.
Grounds
Multiple ground points are supplied to complete the current path through the EMS2000. Grounds are supplied as constants to sensors or as switched grounds to activate components.