Block Diagram
CAN abbreviations
| 15 | Ignition ON (terminal 15) | ECM | Engine control unit |
|---|---|---|---|
| 30 | Battery positive (terminal 30) | L2A | Injector, cylinder 1 |
| A40 | Direct ignition, ignition coil | L2B | Injector, cylinder 2 |
| B166 | Oxygen sensor, mixture regulation, heated | L2C | Injector, cylinder 3 |
| B28 | Camshaft sensor | L2D | Injector, cylinder 4 |
| B39 | Coolant temperature sensor | M8.2 | Tank capacity sensor |
| B41 | Oil level sensor | S41 | Clutch switch |
| B57 | Oxygen sensor, catalytic converter control | S87 | Oil pressure switch |
| B64 | Intake air temperature sensor | Y56 | Exhaust gas recirculation solenoid valve |
| B65 | Knock control sensor |
Block Diagram (Continued)
| A111 | Throttle valve module | S216 | Brake light switch |
|---|---|---|---|
| B30 | Crankshaft pulse pick-up | X125 | Engine compartment electronics module |
| ECM | Engine control unit | Y123 | Tank vent solenoid valve |
Block Diagram (Continued)
| B18 | AC pressure sensor | G8 | Alternator |
|---|---|---|---|
| B22 | Pedal position sensor | HSCAN | High-speed CAN bus |
| B67 | Vacuum air intake sensor | IPC | Instrument assembly |
| CIM | Steering column electronics module | LSCAN | Low-speed CAN bus |
| DIAG | Diagnostic tester | TCM | Automatic transmission control unit |
| ECM | Engine control unit | X97 | Rear electronics module |
Function Table
Wiring harness plug X1 = 64-pin, engine side "M"
Wiring harness plug X2 = 64-pin, vehicle side "K"
| Terminal | Description | Source | Destination |
|---|---|---|---|
| X1-1 | Direct ignition, ignition coil, cylinder 3 | ECM | A40 |
| X1-2 | Direct ignition, ignition coil, cylinder 2 | ECM | A40 |
| X1-3 | Actuation of fuel vent valve | ECM | Y123 |
| X1-5 | Crankshaft sensor (ground) | ECM | B30 |
| X1-8 | Input, alternator, "L" terminal | G8 | ECM |
| X1-9 | Throttle valve sensor (signal line, potentiometer 1) | A111 | ECM |
| X1-10 | Engine coolant temperature sensor (ground) | B39 | ECM |
| X1-12 | Throttle valve sensor (signal line, potentiometer 2) | A111 | ECM |
| X1-13 | Throttle valve sensor (voltage supply, potentiometer 1) | ECM | A111 |
| X1-14 | Throttle valve sensor (voltage supply, potentiometer 2) | ECM | A111 |
| X1-15 | Throttle valve actuator (voltage supply) | ECM | A111 |
| X1-16 | Throttle valve actuator (ground) | ECM | A111 |
| X1-17 | Direct ignition, ignition coil, cylinder 3 | ECM | A40 |
| X1-18 | Direct ignition, ignition coil, cylinder 2 | ECM | A40 |
| X1-21 | Actuation of exhaust gas recirculation valve | ECM | Y56 |
| X1-22 | Crankshaft sensor (signal line) | B30 | ECM |
| X1-23 | Camshaft sensor (signal line) | B28 | ECM |
| X1-26 | The intake air vacuum pressure is registered for calculation of the air mass, MAP sensor (signal line) | B67 | ECM |
| X1-27 | The oil quantity is registered (signal line) | B41 | ECM |
| X1-28 | Actuation of exhaust gas recirculation valve (positional feedback) | Y56 | ECM |
| X1-29 | Camshaft sensor (voltage supply) | ECM | B28 |
| X1-30 | Camshaft sensor (voltage supply) | ECM | B28 |
| X1-31 | Throttle valve actuator (voltage supply) | ECM | A111 |
| X1-32 | Throttle valve actuator (ground) | ECM | A111 |
| X1-33 | Direct ignition, ignition coil, cylinder 1 | ECM | A40 |
| X1-34 | Direct ignition, ignition coil, cylinder 4 | ECM | A40 |
| X1-37 | Crankshaft sensor screening | ECM | B30 |
| X1-39 | Knock sensor (signal line) | B65 | ECM |
| X1-43 | The intake air temperature is registered for calculation of the air mass (signal line) | B64 | ECM |
| X1-44 | Heated oxygen sensor upstream of catalytic converter (signal line) | B166 | ECM |
| X1-45 | The AC refrigerant pressure is registered (voltage supply) | ECM | B18 |
| X1-46 | Throttle valve sensor, potentiometer 1 (voltage supply) | ECM | A111 |
| X1-47 | Main relay actuation, 12 volts to main relay | UEC | ECM |
| X1-48 | Main relay actuation, 12 volts to main relay | UEC | ECM |
| X1-49 | Direct ignition, ignition coil, cylinder 1 | ECM | A40 |
| X1-50 | Direct ignition, ignition coil, cylinder 4 | ECM | A40 |
| X1-52 | Heated oxygen sensor upstream of catalytic converter (heating) | ECM | B166 |
| X1-53 | Heated oxygen sensor downstream of catalytic converter (heating) | ECM | B57 |
| X1-56 | The oil pressure is registered | S87 | ECM |
| X1-57 | Actuation of injector, cylinder 1 | ECM | L2A |
| X1-58 | Actuation of injector, cylinder 3 | ECM | L2C |
| X1-59 | Actuation of injector, cylinder 4 | ECM | L2D |
| X1-60 | Actuation of injector, cylinder 2 | ECM | L2B |
| X1-61 | Heated oxygen sensor downstream of catalytic converter (signal line) | B57 | ECM |
| X1-62 | Knock sensor (ground) | ECM | B65 |
| X1-63 | Air conditioning pressure sensor (voltage supply) | ECM | B18 |
| X1-64 | Main relay actuation, 12 volts to main relay | UEC | ECM |
| X2-2 | Battery positive (terminal 30) | UEC | ECM |
| X2-4 | The AC refrigerant pressure is registered | B18 | ECM |
| X2-5 | Brake light switch | S216 | ECM |
| X2-6 | Connected to terminal X2-59 | ECM | ECM |
| X2-7 | AC solenoid valve | ECM | UEC |
| X2-13 | Brake test switch | S216 | ECM |
| X2-14 | Main relay actuation | UEC | ECM |
| X2-16 | Main relay check | ECM | UEC |
| X2-19 | Battery positive (terminal 30) | UEC | ECM |
| X2-20 | Pedal position sensor, potentiometer 2 (voltage supply) | ECM | B22 |
| X2-22 | Ignition key position | CIM | ECM |
| X2-23 | Starter relay | ECM | UEC |
| X2-24 | Actuation, fan relay 2 | ECM | UEC |
| X2-28 | Relay actuation, fuel pump | ECM | REC |
| X2-31 | Actuation, fan relay 3 | ECM | UEC |
| X2-33 | Pedal position sensor, potentiometer 2 (ground) | ECM | B22 |
| X2-34 | Tank capacity sensor (ground) | ECM | M8.2 |
| X2-35 | Pedal position sensor, potentiometer 1 (voltage supply) | ECM | B22 |
| X2-36 | Pedal position sensor, potentiometer 2 (signal line) | B22 | ECM |
| X2-37 | Pedal position sensor, potentiometer 1 (signal line) | B22 | ECM |
| X2-39 | Actuation, fan relay 1 | ECM | UEC |
| X2-50 | Pedal position sensor, potentiometer 1 (ground) | ECM | B22 |
| X2-52 | Ignition ON (terminal 15) | UEC | ECM |
| X2-53 | Tank capacity sensor (signal line) | M8.2 | ECM |
| X2-59 | Connected to terminal X2-6 | ECM | ECM |
| X2-61 | Clutch switch (cruise control) | S41 | ECM |
| X2-64 | Malfunction indicator lamp MIL | ECM | IPC |
| X2-43 X2-11 HSCAN | Input of information regarding ABS status (status of ABS error message) | ABS | ECM |
| X2-43 X2-11 HSCAN | Input of information regarding CIM status (status of immobiliser error message, cruise control buttons) | CIM | ECM |
| X2-43 X2-11 HSCAN | AC status is communicated to other control units via CAN | ECM | CIM |
| X2-43 X2-11 HSCAN | ECM status is communicated to other control units via CAN for function monitoring (network monitoring) | ECM | ABS AHL CIM EHPS TCM |
| X2-43 X2-11 HSCAN | The current engine speed and accelerator pedal position is made available to other control units via CAN | ECM | ABS CIM EPS TCM |
| X2-43 X2-11 HSCAN | The current engine coolant temperature is made available to other control units via CAN | ECM | CIM TCM |
| X2-43 X2-11 HSCAN | The current engine torque is made available to other control units via CAN | ECM | ABS TCM |
| X2-43 X2-11 HSCAN | Immobiliser information | CIM ECM | ECM CIM |
| X2-43 X2-11 HSCAN | Input of information via the request for torque reduction by ABS with TCS | ABS | ECM |
| X2-43 X2-11 HSCAN | Input of information regarding TCM status (transmission emergency operation, gear engaged and selected shift mode) | TCM | ECM ABS CIM |
| X2-43 X2-11 HSCAN | Input of information regarding transmission temperature | TCM | ECM |
| X2-43 X2-11 HSCAN | Input of information regarding the request for torque reduction by TCM | TCM | ECM |
| X2-43 X2-11 HSCAN | Diagnostics – communication with tester | DIAG ECM | ECM DIAG |
| X2-43 X2-11 HSCAN | The current vehicle speed and distance travelled is made available to other control units via CAN | ECM | CIM EHPS |
| X2-43 X2-11 HSCAN | The ECM receives the wheel speeds for calculating the odometer signal via CAN | ABS | ECM |
| X2-43 X2-11 CAN | The ECM receives the wheel speeds for calculating the vehicle speed signal via CAN | ABS | ECM |
Functional Description
The following new functions have been integrated in the engine control unit and are output to the CAN bus by the ECM:
- Oil level check
- Fuel level check
- Vehicle speed calculation
- ECO Service flex data calculation
Storage of Diagnosis Fault Codes
In order to conform to the statutory EOBD requirements for vehicle self-diagnosis, a so-called freeze frame is stored. This serves to record the operating conditions during recognition of the exhaust emissions-related faults in the engine control. This is performed upon the first exhaust emissions-related fault after initial operation of the vehicle, e.g. after erasing the fault memory. The freeze frame contains data which must be stored in order to record the engine operating conditions as defined by statutory legislation.
Engine Malfunction Telltale and Service Telltale (MIL, Svs)
The self-diagnosis provisions in each engine control unit include two diagnosis telltales, the malfunction indicator lamp MIL (exhaust emissions-related faults) and the service telltale SVS (remaining, non exhaust emissions-related faults).
Immobiliser
The CIM acts as an interface between the ECM, the transponder in the key and the various other control units, the identification of which is employed to determine engine starting authorisation. The CIM begins with the identification as soon as the ignition key is inserted in the ignition lock. When the ignition is switched ON, the ECM transmits information to the CIM and receives information regarding the validity of the transponder key used and the validity of the identification of other control units installed in the vehicle. If the security code from the CIM is correct, the ECM sends an engine start signal to the starter relay. In the case of an error, no start request is enabled by the ECM and a fault code is stored in the ECM.
See also Chapter: Immobiliser – function
Cruise Control
See Chapter: Cruise control – function
Engine Cooling and AC Compressor – Control
The engine control is responsible for the complete engine cooling and AC management in the vehicle, i.e. the radiator fan control, depending on the engine coolant temperature and the system pressure in the AC, as well as the AC compressor control. In general, one suction cooling fan is installed in vehicles. The fans can be switched to several settings.
Electronic Accelerator Pedal
The following signals and components bear direct relevance to the observance/fulfilment of the safety regulations for the electronic accelerator pedal. Pedal position sensor 1 (PPS1), pedal position sensor 2 (PPS2), throttle valve sensor 1 (TPS1), throttle valve sensor 2 (TPS2), throttle valve servo motor
Electronic Accelerator Pedal Emergency Operation Modes
With a view to maximum availability for the driver, various emergency operation modes are available, depending on the particular fault recognised:
- Emergency operation limitation of the permissible throttle valve opening to an applicable maximum value.
Limitation of the throttle valve opening speed.
Brake pedal actuation by the driver is evaluated as idling request.
Limitation of the permissible vehicle acceleration by separate application values for each individual transmission gear.
- Emergency operation (power management)
During emergency operation, the current to the throttle valve motor is interrupted. In addition, software functions are implemented, which make possible limited operation of the vehicle via injection suppression, alternating between cylinders (possibly rotating), ignition retardation and/or other torque-reducing functions.
- Increased engine idling (forced idle)
A suitable engine speed is kept constant, regardless of load, i.e. it is controlled by uphill/downhill inclines and various loading conditions.
- Engine off (walk home)
In this case, the ignition and the injection are switched off.