System Inputs
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
Caution:
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.
Pins supplying ground to the EMS2000 are:
X6000 - 61,62,80,81
X6004 - 114,115
Accelerator Pedal Position Sensor (PWG)
The Accelerator Pedal Position Sensor (PWG) is mounted in the passenger compartment, clipped to a bracket that is bolted to the floor. The PWG is monitored by the EMS2000 for input or speed requests.
The Accelerator Pedal Position Sensor uses two hall sensors with different voltage characteristics and independent power supplies to provide the drivers input request. The Hall sensors receive power (5v) and ground from the EMS2000 and produce linear voltage signals as the pedal is pressed from the LL position (idle) to the VL position (full throttle).
- Hall Sensor 1 - 0.5 to 4.5 volts Driver Request
- Hall Sensor 2 - 0.5 to 2.0 volts Plausibility Check
The Accelerator Pedal Position (PWG) is monitored by the EMS2000 for pedal angle position and rate of movement. As the accelerator is moved, a rising voltage signal from the Hall sensors requests acceleration and rate. The ECM will increase the volume of fuel injected into the engine, advance the ignition timing and open the Throttle Valve.
The "full throttle" position indicates maximum acceleration to the ECM, and in addition effects air conditioning compressor activation.
As the accelerator pedal is released and returned to the rest position by integral springs, a decrease in voltage signals the EMS2000 to activate fuel shut off if the RPM is above idle speed (coasting). The Throttle Valve will be closed and will open enough to maintain idle speed.
The EMS2000 monitors the engine idle speed in addition to the accelerator pedal position and throttle position voltage. If the voltage values have changed (mechanical wear of throttle plate or linkage), the ECM will adjust the throttle plate to maintain the correct idle speed.
The Hall sensors are non-adjustable because the EMS2000 "learns" the throttle angle voltage at idle speed. If the throttle housing/accelerator pedal module is replaced, the ADAPTATIONS MUST BE CLEARED and ADAPTATION PROCEDURE MUST BE PERFORMED using the DISplus. If this is not performed, the vehicle will not start, or will run in "fail-safe" mode.
If this input is defective, a fault code will be stored and the "Malfunction Indicator and/or EML" Light will be illuminated and only limited engine operation is possible.
There are two failure modes of the PWG.
- Failure Mode 1 occurs with a defect in one of the hall effect pedal position sensors. Maximum engine speed will be limited.
- Failure Mode 2 occurs with a defect in both of the hall effect pedal position sensors. Engine speed is limited to approximately 1300 RPM and is reduced to 1000 RPM when the brake pedal is depressed.
Operation of the PWG is checked and monitored by use of the DISplus.
TMap Sensor (MINI COOPER)
The TMAP (Temperature and Manifold Absolute Pressure) sensor contains a Manifold Absolute Pressure (MAP) Sensor and an Intake Air Temperature Sensor.
Manifold Absolute Pressure Sensor
The Manifold Absolute Pressure Sensor is a Piezo resistive pressure gauge that supplies an analog input to the EMS2000 corresponding to the absolute manifold pressure. The signal is used to determine the engine load. The engine load information is used for internal engine control via the EMS2000 and for ASC/DSC (traction control). This sensor has a maximum pressure range of 120 Kpa.
The Manifold Absolute Pressure (MAP) sensor measures the changes in the intake manifold pressure which result from engine load (intake manifold vacuum) and rpm changes; and converts these into a voltage output. By monitoring the sensor output voltage, the EMS2000 knows the manifold pressure. At idle manifold pressure is lower (high vacuum) and output voltage will be about 1 to 2 volts. While at higher pressure or at Wide Open Throttle (lower vacuum) output voltage will be about 4 volts. The EMS2000 uses the MAP sensor to control fuel delivery and ignition timing.
Intake Air Temperature Sensor
The air intake temperature sensor is built into the TMap sensor. Air temperature information is used in conjunction with intake manifold pressure information as supplied by the MAP enabling the EMS2000 to calculate the volume of air being consumed by the engine. The sensor is a NTC type, supplied 5 volts by the EMS2000.
High voltage readings at the EMS2000 indicate high sensor resistance, or low temperature. Low voltage readings indicate low sensor resistance or high temperature.
TMap Sensor (MINI COOPER S)
On the MINI COOPER S the pressure differential is measured across the supercharger to determine the manifold air density.
To measure this differential two sensors are fitted, one on either side of the supercharger. The TMAP is fitted on the manifold pressure side and has the same hardware specification as the MINI COOPER sensor but the maximum pressure range is 250 Kpa. The MAP sensor is fitted upstream of the TMAP between the supercharger and the throttle body and measures the atmospheric pressure. This sensor is the same as the MINI COOPER TMAP but will not have the temperature sensor.
The TMAP sensor is located in the intake manifold where it is exposed to higher than atmospheric pressures as produced by the supercharger. The MAP sensor is located between the supercharger and the EDR, a location not effected by additional pressures from the supercharger.
The first job of the MAP sensor is the measurement of the barometric pressure. Whenever the ignition key is in the "ON" position and the EMS2000 is supplied power from the Main Relay there is no piston action yet and the only reading sent to the computer is the barometric pressure signal (High Voltage).
Second, it measures the absolute pressure in the intake manifold. Absolute pressure is barometric pressure minus the vacuum created by the pistons. So, if the barometer is reading 1.5 Bar at sea level and the manifold vacuum (gauge) is 1.0 Bar at idle, the manifold absolute pressure would be 0.5 Bar.
The EMS2000 compares the voltage outputs from the MAP sensor (ahead of the supercharger) to the outputs received from the TMAP (subject to increased pressures from the supercharger) and calculates air volume drawn into the engine.
- Voltage Reading of 0.6-1.5 volts indicates high vacuum condition (Idle or no load)
- Voltage Reading of 4 volts indicates low vacuum condition (Full Throttle)
TMap and MAP Sensors Failure Symptoms
- Engine difficult to start, stalls at idle and misfires.
TMap and MAP Sensor Testing
- Check status on DISplus status pages (0 - 5 volts) Ensure that voltage changes and does not remain constant at 0 or 5 volts.
- Install BOB on EMS2000 check voltage at appropriate pins
- Check sensor for internal shorts
- Perform TEST PLAN
Intake Air Temp Sensor Failure Symptoms
- Problems with cold starting, poor driveability and an increase in emissions.
- Possible lack of power, particularly noticeable in hot ambient temperatures.
With other possible failure modes the EMS2000 should ensure that the engine will limp home on a default value.
Intake Air Temp Sensor Testing
- Check status on DISplus status pages (0 - 5 volts) Ensure that voltage changes and does not remain constant at 0 or 5 volts.
- Check Sensor Resistance
- Perform TEST PLAN
Engine Coolant Temperature Sensor
The Engine Coolant Temperature Sensor is a Negative Temperature Coefficient thermistor sensor located in the coolant system. The sensor is located in the cylinder head next to the thermostat housing. It is accessed easier with the air box removed.
The Engine Coolant Temperature Sensor is a NTC type sensor. It is used to monitor the engine coolant temperature and has two wires both connected to the EMS2000. The signal is used for fuel control and ignition timing dependent on the engine temperature. The signal is also used to control the radiator fan speed as well as supplying a signal on the CAN-bus to drive the coolant temperature gauge in the instrument cluster. A 5 volt reference signal is supplied to the coolant temp sensor by the EMS2000. High voltage readings at the EMS2000 indicate high sensor resistance, or low temperature. Low voltage readings indicate low sensor resistance or high temperature.
Coolant Temp Sensor Resistance:
Coolant Temperature Sensor Failure Symptoms
- The vehicle may be difficult to start, may run lean when the engine is cold or slightly rich when the engine is hot (default to 'emergency program' mode).
- Driveability of the vehicle will be affected.
- If the sensor output signal fails open, shorted to ground, shorted to 12V or shorted to 5V the EMS2000 will replace the temperature value with a default value.
- If the sensor ground is shorted to 12V or shorted to 5V, temperature gauge will go to full hot and engine cooling fan goes to high when fault is recognized.
Coolant Temperature Sensor Testing
- Check status on DISplus status pages (0 - 5volts) Ensure that voltage changes and does not remain constant at 0 or 5 volts.
- Check Sensor Resistance
- Perform TEST PLAN
EDR Throttle Position Feedback
The EDR throttle plate position is monitored by two integrated potentiometers. The potentiometers provide DC voltage feedback signals as input to the EMS2000 for throttle and idle control functions.
Feedback potentiometer 1 provides a signal ranging from 0.5V (LL) to 4.5V (VL),
Feedback potentiometer 2 simultaneously provides a signal ranging from 4.5V (LL) to 0.5V (VL).
Pot signal 1 is the primary signal, signal 2 is used as a plausibility cross-check through the total range of throttle plate movement.
If there is an open or short in signal 1, signal 2 is used as a temporary substitute providing fail-safe operation (faults stored).
If plausibility errors are detected between Pot 1 and Pot 2 one of two Emergency Modes is activated depending on severity of fault.
Emergency Mode 1
Emergency operation 1 limits the dynamic operation if one of the potentiometers fail. The engine can slowly reach maximum speed with limited power.
Emergency Mode 2
If another fault is encountered in addition to emergency mode 1 or if the plausibility is affected, emergency mode 2 is activated by the EMS2000. Emergency mode 2 is also be initiated by simultaneously pressing both the accelerator pedal and the brake pedal while in emergency mode 1 or if a fault is encountered in the brake light switch diagnosis (see Performance Controls).
When in emergency 2 operation mode, the engine runs very roughly. Throttle response is limited. This mode enables limp home functions.
Additional Monitoring
The EDR safety concept can detect a jammed or binding throttle valve as well as a broken link spring. This fault is detected by the EMS2000 monitoring of the feedback potentiometers from the EDR in relation to the pulse width modulation signal activating the EDR motor.
Crankshaft Sensor
The crankshaft sensor is a primary input to the EMS2000. It is used to determine the speed and position of the engine crankshaft. The sensor is a Hall Effect device. This provides a digital electrical signal that is created as the reluctor ring targets pass the sensor. The reluctor ring tooth pattern consists of 58 targets and a space of two missing teeth grouped together (6� tooth intervals). As the engine rotates the sensor output enables the EMS2000 to determine the crankshaft position and speed.
The missing teeth are essential for correct engine operation. They are used by the EMS2000 as an angular reference point. This information is used in combination with information from the camshaft sensor to determine the correct timing for the spark and fuel delivery.
Diagnosis
During cranking the digital signal produced by the sensor is sent to the EMS2000. The EMS2000 expects to receive a signal of 58 targets and two missing targets. If this signal is received the EMS2000 will synchronize itself to the engine. (The EMS2000 knows crankshaft position.) In the event a faulty or improper signal is received the EMS2000 will not begin or allow injection or ignition.
There is no crankshaft back up facility on the EMS2000 because the camshaft sensor target only produces one pulse per revolution.
Camshaft Sensor
The signal from the camshaft sensor enables the EMS2000 to detect the position of the camshaft in relation to the position of the crankshaft. This allows the EMS2000 to synchronize the fuel injection and ignition spark.
The camshaft sensor is located in the front of the engine cylinder head just below the valve cover. The sensor reluctor ring is bolted to the front of the camshaft.
A digital signal is provided by the sensor in the range of 0-5 volts. The Hall Effect device produces one pulse for each revolution of the camshaft. The reluctor is of a half moon form with a single "tooth" that extends over 180 degs.of the camshaft rotation.
Camshaft Sensor:
Diagnosis
Failure of the camshaft sensor will set a fault. Testing of the sensor is done through the test plan and the measurement system.
Camshaft sensor failure will cause the injection system to default into a semi-sequential mode.
Knock Sensors
Knock Sensors are required to prevent detonation (pinging) from damaging the engine. The EMS2000 will retard the ignition timing (cylinder selective) based on the input of this sensor. Detonation occurs due to:
- High Compression Ratio
- Poor Quality Fuel
- High Level of Cylinder Filling
- Maximum Timing Advance Curve
- High Intake and Engine Temperatures
- Combustion Chamber Carbon Build-up
The knock sensor is a "Piezo-electric accelerometer" producing an output voltage proportional to mechanical vibration (knock) produced by the engine. Knock is caused by high-pressure waves of uncontrolled spontaneous combustion of gasses in the cylinder.
The EMS2000 receives a signal from the knock sensor, filters out any noise and calculates if the engine is knocking. During knock the crystal oscillation increases, the EMS2000 compares the signal received to known signal profiles in the memory.
From the camshaft and crankshaft signals supplying information regarding the position of the engine in it's cycle, the EMS2000 is able to determine which cylinder is knocking and will retard the ignition, on that particular cylinder until the knock is eliminated. It then gradually advances the ignition again towards the original setting until knock occurs again.
Knock Sensor Fault Symptoms
- The EMS2000 will not be able to detect and correct for engine knock resulting in a "pinging" sound within the engine.
- The engine will lack power and fuel consumption will be affected.
- The knock strategy ensures that the engine defaults to a safe ignition value.
LDP System (Leak Diagnosis Pump)
Vapors containing Hydrocarbons form in the vehicles fuel tank and to prevent them from venting to atmosphere, legislation in the USA demands on-board monitoring of the fuel system sealing on all vehicles powered by an Internal Combustion engine. Beginning with Model Year 2000 these regulations were tightened, and call for detection of a 0.5 mm (0.02 inch) leak.
- The EVAPS system used on the MINI will be the Siemens Leak Detection Pump (LDP). The LDP system is located above the right rear inner fender liner.
The LDP is an electrically/vacuum-actuated device that will pressurize the evaporative emission system for the purpose of detecting leaks and verifying canister purge valve integrity. It has an integrated Canister Vent Valve (CVV) that controls the atmospheric venting of the fuel vapor storage canister.
The LDP assembly is only replaceable as a complete unitized component, however, it is separate from the charcoal canister.
The upper chamber contains an integrated reed switch that produces a switched high/low voltage signal that is monitored by the EMS2000. The switch is opened by the magnetic interruption of the metal rod connected to the diaphragm when in the top dead center position. The repetitive up/down stroke is confirmation to the EMS2000 that the valve is functioning and the basis for determining if a leak is present in the system. The EMS2000 monitors the length of time it takes for the reed switch to open, which is opposed by pressure under the diaphragm in the lower chamber. If this component or its circuits are defective, a fault code will be set and the "Malfunction Indicator Light" will illuminate when the OBD II criteria is achieved.