Contents Wiring diagrams Section: Testing & Diagnostics All sections

Mixture Formation (Coupe): Other Smart Fortwo II

Testing & Diagnostics 11 illustrations ~3063 words

Safety information: Mixture formation - AS07.00-Z-9999ZZ

MODEL all

Risk of death caused by contact with parts conducting high voltages. ENGINE 642 Risk of explosion caused by fuel igniting. Risk of injury to skin and eyes caused by fuel spraying out at high pressure ENGINE 611, 612, 613, 628, 629, 639, 640, 642, 646, 647, 648, 660, 668, 651 Risk of explosion caused by fuel igniting. Risk of injury to skin and eyes caused by fuel spraying out at high pressure ENGINE 470.9, 471.9, 473.9 Risk of explosion caused by ignition or explosion of fuel. Risk of injury to skin and eyes caused by fuel jets or leakage. ENGINE 112, 272, 271.942 Risk of explosion caused by test oil being ignited. Risk of injury to skin and eyes caused by test oil streaming out ENGINE 601.942 /970, 402.970, 441.980, 446.938, 384, 444.901, 447.903

ME gasoline injection and ignition system - BA07.61-P-1000-01B

Engine 132, 160

NumberDesignationEngine 132.9Engine 160.910Engine 160.920Engine 160.921
BA07.61-P-1001-01BBolt at throttle valve actuatorNm9
BA07.61-P-1002-01BBolt, electronic accelerator adjusting motor to intake manifoldNm99
BA07.61-P-1003-01BBolt, throttle valve actuator to intake manifold/ charge air manifoldNm9

ME-SFI [ME] GASOLINE INJECTION AND IGNITION SYSTEM

NumberDesignationEngine 160.922Engine 160.923
BA07.61-P-1001-01BBolt at throttle valve actuatorNm
BA07.61-P-1002-01BBolt, electronic accelerator adjusting motor to intake manifoldNm99
BA07.61-P-1003-01BBolt, throttle valve actuator to intake manifold/ charge air manifoldNm

ME-SFI [ME] GASOLINE INJECTION AND IGNITION SYSTEM

Fuel Distributer - BA07.52-P-1000-01D

Engine 132

NumberDesignationEngine 132.9
BA07.52-P-1001-01DNm9
BA07.52-P-1002-01DNm9

Start procedure, function - GF07.15-P-2001MCU

ENGINES 132.9 in MODEL 451.3 /4

Scheme 34

Scheme 34: Start procedure, function - GF07.15-P-2001MCU

The start process includes the following partial functions

  1. Circuit 15 On
  2. START
  3. Start quantity control
  4. Post-start enrichment

Circuit 15 ON

  1. The SAM control unit checks drive authorization and applies an appropriate signal to the CAN.
  2. The ME-SFI [ME] control unit requests the CHECK ENGINE indicator lamp in the instrument cluster to light up shortly.
  3. The fuel pump with fuel level sensor is actuated via the SAM control unit for about 25 seconds. This approach is particularly required after long periods of being switched off. This ensures that the fuel injection valves are supplied with sufficient fuel during starting. An engine start must be completed, however, before repeated actuation of the fuel pump with fuel level sensor.

Starting

The start function is activated by turning the transmitter key from position 1 (circuit 15 On) to position 2 (circuit 50 On) in the ignition/ starter switch.

Actuation of the starter takes place directly by the SAM control unit.

The start process is ended again as soon as terminal 50 is no longer applied at the SAM control unit or the engine cranking speed is reached.

Start quantity control

As soon as the first rpm signal is recognized by the crankshaft position sensor during the start process, the SAM control unit energizes the fuel pump with fuel level sensor permanently. In order to facilitate starting of a cold engine, fuel is also injected during the starting procedure. The increase in injection quantity (start quantity) takes place depending on the coolant temperature and is achieved through extending the injection time.

The start quantity control is enabled after starter recognition and remains active until a stable idle speed is recognized by the ME-SFI [ME] control unit.

The higher the coolant temperature, the lower is the start quantity enable by the ME-SFI [ME] control unit.

Post-start enrichment

When the engine is cold, fuel precipitates on the walls of the intake manifold and is not available to the engine for combustion. The missing fuel volume is compensated by the post-start enrichment function.

After the cold start the fuel-air mixture is enriched for short time through longer injection times of the fuel injection valves.

Post-start enrichment is achieved by the ME-SFI [ME] control unit and is dependent on the coolant temperature at engine start.

Instrument cluster, component descriptionA1GF54.30-P-6000MCU
Coolant temperature sensor, component descriptionB11/4GF07.04-P-6040MCC
Component description for the intake manifold pressure sensorB28GF07.04-P-6062MCC
Crankshaft position sensor, component descriptionL5GF07.04-P-6010MCC
Component description for fuel pumpM3/3GF47.20-P-2000MCC
ME-SFI [ME] control unit, component descriptionN3/10GF07.61-P-6000MCU
SAM control unit, component descriptionN10/10GF54.21-P-4157MCU
Ignition coils, component descriptionT1/1, T1/2, T1/3GF15.10-P-2100MCC
Fuel injection valves, component descriptionY62/1, Y62/2, Y62/3GF07.03-P-6010MCC

Scheme 35

Scheme 35: (ME-SFI) motor electronics fuel injection and ignition system, location of components - GF07.61-P-00

Scheme 36

Scheme 36

Scheme 37

Scheme 37

Scheme 38

Scheme 38

Scheme 39

Scheme 39: Motor electronics (ME-SFI) fuel injection and ignition system control unit, input signals - GF07.61-

Scheme 40

Scheme 40: Motor electronics (ME-SFI) fuel injection and ignition system control unit, output signals - GF07.61

Motor electronics (ME-SFI) fuel injection and ignition system, function - GF07.61-P-0001MCU

ENGINES 132.9 in MODEL 451.3 /4

The ME-SFI [ME] control unit (N3/10) is the master control unit for the engine control and a subscriber on the Control Area Network (data bus/CAN bus) (CAN).

Functions

  1. Start process Terminal 15 On Starting Start quantity control Post-start enrichment
  2. Driving mode idle speed control warm-up control acceleration enrichment deceleration fuel shutoff antiknock control camshaft adjustment fan control maximum engine speed limitation external quantity intervention O2-sensor heater two-sensor control fuel regeneration tank leaktightness monitoring safety fuel shutoff catalytic converter heating secondary air injection ignition system
  3. On-board diagnosis readiness code fault detection consequential fault CHECK ENGINE indicator lamp (A1e26) fault memory limp-home mode function chain

(ME-SFI) motor electronics fuel injection and ignition system, location of components GF07.61-P-0001-01MCU Motor electronics (ME-SFI) fuel injection and ignition system control unit, input signals GF07.61-P-0001-06MCU Motor electronics (ME-SFI) fuel injection and ignition system control unit, output signals GF07.61-P-0001-07MCU Electrical function diagram for engine control ME-SFI [ME] PE07.61-P-2050MCU Wiring diagram, fuel injection and ignition system ME-SFI PE07.61-P-2000MCU Start procedure, function GF07.15-P-2001MCU ME-SFI driving mode, function GF07.61-P-2005MCU On-Board Diagnosis (OBD) ME function GF07.61-P-1001MCC

ME-SFI driving mode, function - GF07.61-P-2005MCU

ENGINES 132.9 in MODEL 451.3 /4

Scheme 41

Scheme 41: ME-SFI driving mode, function - GF07.61-P-2005MCU

The driving mode includes the following subfunctions

  1. Idle speed control: The ME-SFI [ME] control unit regulates a stable idle speed under all operating conditions.
  2. Warm-up control: The engine is brought rapidly up to operating temperature.
  3. Acceleration enrichment Dynamic enrichment prevents jerking when accelerating.
  4. Overrun fuel shutoff The braking effect of the engine is increased in overrun mode and fuel consumption reduced
  5. Antiknock control: The antiknock control guarantees knock-free operation of the engine with various fuel qualities and under all operating conditions.
  6. Camshaft adjustment Camshaft adjustment lowers emissions and increases performance
  7. Fan control The fan motor is actuated to reduce the coolant temperature
  8. Maximum engine speed limitation For protection of the engine and the drive train the engine speed is limited
  9. External quantity intervention The injection quantity is adapted to various driving modes.
  10. O2 sensor heater: The O2 sensor heater is used to bring the O2 sensors rapidly up to operating temperature.
  11. Two-sensor control The effect of the catalytic converter is monitored by the signals from the O2 sensor upstream of CAT and by the signals from the O2 sensor downstream of CAT
  12. Fuel regeneration: Fuel vapors are fed to the engine. Moreover, fuel vapors are not allowed to escape into the atmosphere.
  13. Checking for leaks in the tank: Gross, fine and very fine leaks are checked by measuring the pressure in the tank.
  14. Safety fuel shutoff In the event of a crash, the fuel pump is shut off and the fuel injection valves are actuated briefly
  15. Catalytic converter heating The catalytic converter is brought rapidly to the operating temperature
  16. Secondary air injection: In addition, fresh air is let into the exhaust flow to improve the exhaust emission values.
  17. Ignition system: A static high-voltage distribution with 3 single-spark ignition coils is used.

Idle speed control

The throttle valve actuator controls the idle speed by altering the position of the throttle valve. Actuation is by the ME-SFI [ME] control unit.

The ME-SFI [ME] control unit regulates the idle speed according to the input signals for different engine loads (e.g. a switched on refrigerant compressor).

The ME-SFI [ME] control unit evaluates signals from the following components for idle speed control

  1. Camshaft Hall sensor
  2. Coolant temperature sensor
  3. Intake manifold pressure sensor
  4. Accelerator pedal sensor
  5. Crankshaft position sensor
  6. Throttle valve actuator

Warming-up control

After the start process the fuel-air mixture is further enriched via the warm-up control.

The warm-up control compensates for the fuel unavailable for combustion due to precipitation on the cold inner walls of the intake manifold.

The engine is assigned an additional fuel quantity by the ME-SFI [ME] control unit according to a performance map. To do this, the actuation period of the fuel injection valves is extended accordingly.

Warm-up control is dependent on

  1. Coolant temperature
  2. Engine speed
  3. Engine load

Acceleration enrichment

The opening of the throttle valve is dependent on the accelerator pedal sensor.

For rapid opening of the throttle valve the mixture goes lean for a short time.

Therefore a short-term mixture adaptation takes place in that the ME-SFI [ME] control unit assigns the engine an additional fuel quantity.

Acceleration enrichment is dependent on

  1. Coolant temperature
  2. Accelerator pedal position
  3. Engine speed
  4. Engine load

Inertia fuel shutoff

The braking effect of the engine in the overrun mode is increased and the fuel consumption is reduced by means of the overrun fuel shutoff.

In overrun mode, the ME-SFI [ME] control unit switches off the fuel injection valves depending on the temperature and the speed.

The fuel injectors are operated again, when the accelerator pedal is depressed or when idle speed is reached, and no further overrun mode exists.

Anti-knock control [AKC]

The antiknock control ensures knock-free operation of the engine at all engine speeds, for all fuel grades and under all operating conditions. To do this for uncontrolled combustion (knocking) the ignition timing is set to "retard".

If knocking continues to occur, the ignition timing (depending on engine speed) continues to be retarded in stages until maximum retardation is achieved.

If knock-free combustion is restored, the retardation is reduced in stages after a few ignitions (depending on engine speed) until the normal performance map value is achieved or knocking once again occurs.

Input signals for anti-knock control

  1. Knock sensor
  2. Camshaft Hall sensor
  3. Coolant temperature sensor
  4. Accelerator pedal sensor
  5. Crankshaft position sensor

Camshaft adjustment

The adjustment of the camshaft takes place electrohydraulically via the camshaft timing solenoid and the camshaft adjuster. Here a control plunger in the adjustable camshaft timing solenoid ensures that the applied engine oil pressure is passed through to the respective connection on the camshaft adjuster.

The intake camshaft can now be adjusted by turning the adjuster to "advanced" (large valve overlap) or "retarded" (small valve overlap).

The adjustment time is dependent on the engine oil pressure at the adjuster, oil viscosity and oil temperature.

Camshaft adjustment is used to reduce pollutants in the exhaust gas and to increase the performance of the engine.

In the case of failure of the camshaft Hall sensor, camshaft adjustment is disabled

Fan control

The ME-SFI [ME] control unit decides according to a performance map about switching on the coolant fan motor. Depending on the coolant temperature and operation of the air conditioning system, the fan motor is switched on. Actuation takes place via the SAM control unit.

Maximum engine speed limitation

The ME-SFI [ME] control unit detects the engine speed via the crankshaft position sensor signal. This is limited to protect the engine and the drive train through retarding the ignition timing and cutting out the fuel injection valves.

The ME-SFI [ME] control unit also asks for the current gear range from the automated manual transmission control unit in order, if necessary, to initiate an upshift. If the throttle valve actuator is defective or signals implausible, the engine speed is also limited.

External intervention in the fuel quantity

With external quantity intervention, the engine torque is reduced (e.g. for an ESP regulation) by the ME-SFI [ME] control unit. A reduction of the engine torque takes place through reduction of the injection quantity.

The ME-SFI [ME] control unit receives appropriate signals for this via the CAN from

  1. Automated manual transmission control unit Shift process
  2. ESP control unit ESP regulation

O2 sensor heater

The O2 sensor downstream of TWC and the O2 sensor upstream of TWC only allow lambda regulation above an operating temperature of about 300°C. In order to reach this temperature as quickly as possible the O2 sensors are fitted with an integral heater. The O2 sensor heater is actuated by the ME-SFI [ME] control unit. Rapid heating of the sensors means a high degree of control is achieved, even at low exhaust temperatures.

Two-sensor control

The ME control unit uses the signal from the O2 sensor downstream TWC and the O2 sensor upstream TWC to determine the mean Lambda value. This value is compared with a stored value for optimum exhaust emissions.

If the deviation is too large after a number of measurements, a correction variable is determined for the lambda control.

Using the correction variable aging of the O2 sensor upstream of TWC is compensated for within certain limits. If the correction variable exceeds the limit value, a new O2 sensor upstream of TWC must be installed.

The correction values are map-controlled and are implemented by the ME control unit by adapting the fuel injection. If the limits are exceeded or if the plausibility check of the signal from the O2 sensor downstream of TWC and O2 sensor upstream of TWC is negative, the CHECK ENGINE indicator lamp (A1e26) in the instrument cluster lights up.

The O2 sensor signal downstream of TWC [KAT] and O2 sensor signal upstream of TWC [KAT] is also used to monitor the effect of the catalytic converter

Fuel regeneration

The evaporative emission control system prevents fuel vapors escaping to atmosphere. The fuel vapors are stored in the activated charcoal filter and then sent later to the engine for combustion.

The fuel vapors from the fuel tank flow through the purge line and are stored in the activated charcoal filter. In driving mode the tank vent valve opens and the fuel vapors are led to combustion. For a cold engine or a lower air mass (e.g. neutral) the tank vent valve is closed by the ME-SFI [ME] control unit and the combustion of fuel vapors interrupted. This leads to better running characteristics of the engine in partial load operation.

The ME-SFI [ME] control unit requires the following information for actuation of the tank vent valve

  1. Coolant temperature
  2. Intake manifold pressure

Fuel tank leak test

Test requirements

  1. Engine at idle
  2. Vehicle stationary
  3. Intake air temperature <45°C
  4. Coolant temperature for engine start <100°C
  5. Drive position "D" or "R" is engaged
  6. Fuel level in the fuel tank between approximately 1/4 and 3/4

The fuel system is tested for leaks in three stages (function chain).

The leak test detects leaks with a diameter of 0.5 mm and more

  1. Test for gross leaks (equal to or greater than 3 mm)
  2. Test for fine leaks (equal to or greater than 1 mm)
  3. Test for very fine leaks (equal to or greater than 0.5 mm)

Test for gross leak

The outside air shutoff valve is closed and the tank vent valve is opened. Intake manifold vacuum present in fuel tank.

This vacuum is measured by the tank pressure sensor.

If no vacuum is formed in the fuel tank, there is a larger leakage (for example, open tank cap, loose hose line). The test is interrupted and the fault 'gross leak' is registered.

Test for fine leak

The tank vent valve is closed at a vacuum of around -6 mbar. The system is closed and thereby airproof. The vacuum is them measured for approx. 30 seconds. The vacuum must not reduce more rapidly than 0.3 to 0.5 mbar per second (depends on fuel level). If the vacuum drops more rapidly, there is a fine leak. The test is interrupted and the fault 'fine leak' is registered.

Test for very fine leak

If no minor leak has been detected, the purge system is briefly enabled and a vacuum of approx. -6 mbar is built up again. The vacuum must not drop any faster than 0.1 to 0.15 mbar per second for a closed system (depending on the level of fuel in the tank).

If the vacuum drops more rapidly, the fault 'very fine leak' is registered.

The outside air shutoff valve is opened again after the tests.

If a gross, fine or a very fine leak is detected, the CHECK ENGINE indicator lamp is actuated by the ME-SFI [ME] control unit via the CAN.

Safety fuel shutoff

If the ME-SFI [ME] control unit receives a crash signal from the restraint systems control unit via the CAN, it switches off the fuel pump with fuel level sensor and actuates the fuel injection valves for a short time to make the fuel system become unpressurized.

Catalytic converter heating

The catalytic convertor heater rapidly brings the catalytic convertor to the operating temperature In this way the exhaust gas emissions after a cold start are strongly reduced. Controlling of the catalytic converter heating is by the ME-SFI [ME] control unit.

The ignition timing is adjusted to 'retarded' in the neutral depending on the coolant temperature in order to increase the exhaust temperature. By delaying the ignition timing point and the resultant combustion in the exhaust tract, the catalytic converter is heated rapidly.

The idle speed is adjusted in line with the coolant temperature.

Secondary air injection

Function requirement

  1. Coolant temperature between 7°C and 36°C

The secondary air injection causes afterburning of the unburnt hydrocarbons on the exhaust side. As a result, the catalytic converter reaches its operating temperature more quickly after the cold start and the emissions in the exhaust are reduced.

The secondary air is provided by the secondary air injection pump, which is actuated by the ME-SFI [ME] control unit via the secondary air injection relay for t = 33 s. The secondary air injection pump switchover valve actuates the secondary air valve via a vacuum, which enables air supply into the exhaust manifold. The secondary air injection pump switchover valve is also actuated by the ME-SFI [ME] control unit.

The actuation is aborted by the ME-SFI [ME] control unit at an engine speed of more than 4000 rpm. If the engine speed then falls below 4000 rpm, the secondary air injection is restarted.

Ignition system

Three single-spark ignition coils are used at the spark plugs (R4). Actuation of ignition coils takes place over the ME-SFI [ME] control unit.

Static high-voltage is distributed directly to the spark plugs without an ignition distributor.

Advantages of the rotorless high voltage distribution are

  1. significantly lower electromagnetic interference level (no naked sparks)
  2. No rotating parts (no wear)
  3. Noise reduction
  4. No need for ignition lines

The ME-SFI [ME] control unit evaluates signals from the following components for actuation of the ignition coils

  1. Knock sensor
  2. Camshaft Hall sensor
  3. Coolant temperature sensor
  4. Intake manifold pressure sensor
  5. Accelerator pedal sensor
  6. Crankshaft position sensor
  7. Throttle valve actuator
Three-way catalytic converter, component descriptionGF49.10-P-2010MCU
Instrument cluster, component descriptionA1GF54.30-P-6000MCU
Component description of refrigerant compressorA9 For code (I01) Air conditioning PlusGF83.55-P-2108MCU
Knock sensor, component descriptionA16GF07.04-P-6030MCC
Fuel tank pressure sensor, component descriptionB4/3GF47.30-P-2101MCU
Camshaft Hall sensor, component descriptionB6/1GF07.04-P-6020MCC
Coolant temperature sensor, component descriptionB11/4GF07.04-P-6040MCC
Component description for the intake manifold pressure sensorB28GF07.04-P-6062MCC
Accelerator pedal sensor, component descriptionB37GF30.20-P-2010MCU
Component description for O2 sensorG3/1, G3/2GF07.04-P-6100MCU
Secondary air injection pump relay, component descriptionK64GF14.30-P-2060MCU
Crankshaft position sensor, component descriptionL5GF07.04-P-6010MCC
Component description for fuel pumpM3/3GF47.20-P-2000MCC
Fan motor, component descriptionM4/2GF20.20-P-1000MCU
Throttle valve actuator, component descriptionM16/6GF30.20-P-2020MCC
Secondary air injection pump, component descriptionM33GF14.30-P-2050MCU
Restraint systems control unit, component descriptionN2/7GF91.60-P-4048MCU
ME-SFI [ME] control unit, component descriptionN3/10GF07.61-P-6000MCU
SAM control unit, component descriptionN10/10GF54.21-P-4157MCU
Component description for the automated manual transmission control unitN15/6GF26.19-P-1010MCU
Component description for the heater/air conditioning operating unitN23 For code (I01) Air conditioning PlusGF83.40-P-3001MCU
ESP control unit, component descriptionN47-5GF42.45-P-5118MCU
Component description for the oil pressure switchS41/1GF18.40-P-4000MCC
Ignition coils, component descriptionT1/1, T1/2, T1/3GF15.10-P-2100MCC
Secondary air injection pump switchover valve, component descriptionY32GF14.30-P-2055MCU
Adjustable camshaft timing solenoid, component descriptionY49GF05.20-P-2100MCC
Activated charcoal filter shutoff valve, component descriptionY50GF47.31-P-2100MCU
Component description for the tank vent valveY58GF47.30-P-4037MCC
Fuel injection valves, component descriptionY62/1, Y62/2, Y62/3GF07.03-P-6010MCC

Electrical function diagram for engine control ME-SFI [ME] - PE07.61-P-2050-99MCU

ENGINE 132 in MODEL 451

Electrical function diagram for engine control ME-SFI [ME] - PE07.61-P-2050MCU

ENGINE 132 in MODEL 451

PE07.61-P-2050-99MCUElectrical function diagram for engine control ME-SFI [ME]PE07.61-P-2050-99MCU
PE07.61-P-2050-60MCULegend of electrical function diagram for engine control ME-SFI [ME]PE07.61-P-2050-60MCU
OV00.01-P-1901-03MCCUse of wiring diagramsOV00.01-P-1901-03MCC
OV00.01-P-1901MCUSearch aid for all wiring diagram groupsOV00.01-P-1901MCU
OV00.01-P-1001-27MCAbbreviations for wiring diagramsOV00.01-P-1001-27MC
OV00.01-P-1001-28MCAbbreviations of signal and circuit designations for wiring diagramsOV00.01-P-1001-28MC
GF00.19-P-1000MCULocation and assignment of line and connectorsGF00.19-P-1000MCU
GF00.19-P-2000MCULocation and assignment of ground pointsGF00.19-P-2000MCU
GF00.19-P-3000MCULocation and assignment of Z connector sleeves (line connectors in wiring harness)GF00.19-P-3000MCU
PE07.00-P-1100MCUFurther wiring diagramsPE07.00-P-1100MCU
PE26.00-P-1100MCUFurther wiring diagramsPE26.00-P-1100MCU
PE42.00-P-1100MCUFurther wiring diagramsPE42.00-P-1100MCU
PE46.00-P-1100MCUFurther wiring diagramsPE46.00-P-1100MCU
PE54.00-P-1100MCUFurther wiring diagramsPE54.00-P-1100MCU
PE83.00-P-1100MCUFurther wiring diagramsPE83.00-P-1100MCU

450 589 09 21 00 Pressure gauge - WS07.00-P-0100B

FG 07/Set B

ENGINE 132, 160, 660

Use

Pressure gauge for checking the fuel pressure.

Note. Fuel pressure gauge 0...10 bar Smart No. 0005182.

Scheme 42

Scheme 42: 450 589 09 21 00 Pressure gauge - WS07.00-P-0100B

Scheme 43

Scheme 43

450 589 18 21 00 Vacuum pump - WS07.00-P-0102B

FG 07/Set B

MODEL 450, 451, 452

Use

Vacuum pump for inspection of leaktightness and performance of vacuum pump on a diesel engine as well as inspection of leaktightness of vacuum line on a gasoline engine.

Note. Vacuum pump Smart No.: 0014669

Scheme 44

Scheme 44