Component description for CDI control unit - GF07.16-P-6000OHS
ENGINES 642.862 in MODEL 221.026 /126
ENGINES 642.868 in MODEL 221.083 /183
Vehicle view from left front
Location
The CDI control unit is located in the engine compartment next to the brake booster.
Task
The CDI control unit operates in an electrical network of sensors and actuators to form the engine control system for engine 642.8.
The following systems and functions are controlled and coordinated by the CDI control unit according to input signals:
- Fuel supply
- Preglow system control
- Injection quantity control
- Diagnosis and fault storage
- Drive authorization system and immobilizer
- Heat management
- Torque interface
- Alternator interface
- Exhaust gas recirculation
- Emission control
The CDI control unit has an internal atmospheric pressure sensor.
Input and output signals
The following input signals are evaluated by the engine control and issued in the respective output signals:
- Direct input signals
- Direct output signals
- LIN signals
- CAN input signals
- CAN output signals
Direct input signals
- Circuit 15
- Circuit 30 (fused)
- Circuit 31
- Terminal 87
- Oil temperature sensor (B1)
- Left hot film mass air flow sensor (B2/6)
- Intake air temperature sensor (B2/6b1)
- Right hot film mass air flow sensor (B2/7)
- Intake air temperature sensor (B2/7b1)
- Rail pressure sensor (B4/6)
- Charge pressure sensor (B5/1)
- Camshaft Hall sensor (B6/1)
- Coolant temperature sensor (B11/4)
- Exhaust gas recirculation temperature sensor (B16/14) (for code (U42) Blue TEC diesel exhaust treatment (SCR) and code (494) USA version)
- Temperature sensor upstream of SCR catalytic converter (B16/15) (for code (U42) BlueTec (SCR) diesel exhaust treatment
- Charge air temperature sensor (B17/8)
- Temperature sensor upstream of CAT (B19/7) (for code (U42) BlueTec (SCR) diesel exhaust treatment
- Temperature sensor upstream of diesel particulate filter (B19/9) (for code (474) Particulate filter)
- Temperature sensor upstream of turbocharger (B19/11) (for code (474) Particulate filter)
- Pressure sensor downstream of air filter (B28/5)
- Pressure differential sensor (DPF) (B28/8) (for code (474) Particulate filter)
- Pressure differential sensor DPF for OBD (B28/16) (for Code (U42) BlueTEC (SCR) diesel exhaust treatment and code (494) USA version)
- Accelerator pedal sensor (B37) - potentiometer 1
- Accelerator pedal sensor - potentiometer 2
- Fuel temperature sensor (B50)
- Exhaust back pressure sensor (B60)
- Crankshaft Hall sensor (B70)
- EGR cooler bypass flap Hall sensor (B90) (for code (U42) BlueTec (SCR) diesel exhaust treatment and code (494) USA version)
- Right hand and left hand intake port shutoff end position sensor (B96/1, B96/2) (for code (U42) BlueTec (SCR) diesel exhaust treatment and code (494) USA version)
- O2 sensor upstream of CAT (G3/2)
- Engine and air conditioning electric suction fan with integrated control (M4/7), diagnostic data
- Actual value potentiometer 1 (M16/6r1) throttle valve
- Crash signal from the restraint system control unit (N2/7)
- Oil level check switch (S43)
Direct output signals
- O2 sensor upstream of CAT - O2 sensor heater
- Throttle valve actuator (M16/6)
- Intake port shutoff motor (M55)
- Circuit 15 (2)/spare 1 relay (changeover contact) (N10/1kD)
- Circuit 50 relay, starter (N10/1kH)
- Circuit 87 relay, engine (N10/1kC)
- Vent line heater element ()R39/1
- Engine and air conditioning electric suction fan with integrated control - specified speed of the fan
- Accelerator pedal sensor - reference ground of potentiometers 1 and 2
- Two-disk thermostat heating element (R48)
- Left exhaust gas recirculation positioner (Y27/9)
- Pressure regulator valve (Y74)
- Cylinder 1 fuel injector (Y76y1)
- Cylinder 2 fuel injector (Y76y2)
- Cylinder 3 fuel injector (Y76y3)
- Cylinder 4 fuel injector (Y76y4)
- Cylinder 5 fuel injector (Y76y5)
- Cylinder 6 fuel injector (Y76y6)
- Boost pressure regulator (Y77/1)
- EGR [AGR] cooler bypass flap switchover valve (Y85)
- Quantity control valve (Y94)
- LH switchable engine mount (Y123) (for 4MATIC)
- RH switchable engine mount (Y123/1) (for 4MATIC)
- Coolant pump switchover valve (Y133)
- Fuel pump control unit (N118) - fuel pump ON ground signal
- Fuel pump relay (N10/2kS) as of 06/11 for actuation of the A/C compressor magnetic clutch (A9y1)
LIN signals
- Alternator interface via drive LIN (LIN C1)
- Alternator (G2)
- Glow time output stage (N14/3) - actuation of various glow functions and transmission of system errors, heating element actuation and signal for the fuel filter condensation level condensation sensor with heating element (B76/1)
CAN input signals
Instrument cluster (A1)
- Fuel reserve signal
Restraint systems control unit (N2/7)
- Crash signal
AAC control unit (N22/1)
- Specified fan speed request
- Air conditioning, status Engine torque request
- Request for actuation of A/C compressor magnetic clutch (as of 06/11)
ESP control unit (N47-5)
- Vehicle speed
- Wheel speed signal
- Brake recognition
- Cruise control request
- Engine torque request
NOx sensor control unit downstream of diesel particulate filter (N37/7) (for code (U42) BlueTec (SCR) diesel exhaust treatment)
- NOx concentration in the exhaust
- O2 concentration in the exhaust
NOx sensor control unit downstream of SCR catalytic converter (N37/8) (for code (U42) BlueTec (SCR) diesel exhaust treatment)
- NOx concentration in the exhaust
- O2 concentration in the exhaust
Video and radar sensor system control unit (N62/2) (for code (233) DISTRONIC PLUS, code (237) Active Blind Spot Assist and code (238) Active Lane Keeping Assist)
- Engine torque request
EIS [EZS] control unit (N73)
- Start enable (drive authorization system)
Fuel system control unit (N118)
- Fuel pressure
- Self-diagnosis data
- Requested diagnostic data
AdBlue® control unit (N118/5) (for code (U42) BlueTEC (SCR) diesel exhaust treatment
- Reduction agent quantity to be injected for NOx reduction
- Reduction agent quantity to be injected for cooling the AdBlue® metering valve (Y129)
- Fill level status in the AdBlue® tank
- Requested diagnostic data
Electric controller unit (VGS) (Y3/8)
- Drive position
- Transmission mode
- Actual gear, target gear
- Engine torque reduction request
- Starter enable in selector lever position "P, N"
- Engine idle specified speed (for actuation of the torque converter lockup clutch)
- Status of torque converter lockup clutch
- Emergency transmission limp-home mode
CAN output signals
Instrument cluster (A1)
- Engine oil level too low
- Circuit 61 signal (generated by CDI control unit)
- Fuel consumption (the trip computer is informed about the current fuel consumption by means of square-wave pulse packages (1 pulse = 0.2 l/h))
NOx sensor control unit downstream of diesel particulate filter (N37/7) (for code (U42) BlueTec (SCR) diesel exhaust treatment
- Diagnosis request
NOx sensor control unit downstream of SCR catalytic converter (N37/8) (for code (U42) BlueTec (SCR) diesel exhaust treatment)
- Diagnosis request
EIS [EZS] control unit (N73)
- Start enable request (drive authorization system)
Fuel system control unit (N118)
- Fuel pump ON
- Specified fuel pressure
- Diagnosis request
AdBlue® control unit (N118/5) (for code (U42) BlueTEC (SCR) diesel exhaust treatment
- Request for reduction agent injection
- Specification of the reduction agent quantity to be injected
- Specification of the run-on period of the control units
- Diagnosis request
Electric controller unit (VGS) (Y3/8)
- Requests for catalytic converter heating
- Switching request
- Engine torque
- Engine coolant temperature
- Engine oil temperature
- Engine speed
- Engine load
- Kickdown
- Engine speed limitation active
- Limp-home mode engine control
Design
The housing of the CDI control unit is made of die-cast aluminum and the cover is made of corrosion-proof sheet steel. The CDI control unit is water proof and dust proof.
The housing contains the 32-bit measuring and control electronics for the engine control.
Voltage supply
The CDI control unit is "circuit 30 fused" and also supplied with a voltage for ignition ON by "circuit 87". In the operating voltage range it has both short-circuit protection and reversed polarity protection. Voltage is supplied through several pins connected in parallel to relieve the electrical connectors.
Ground connection
The "circuit 31" ground connection consists of several ground lines to the electronic ground (LH footwell) (W34/1).
Computer run-on
When the CDI control unit receives the signal "circuit 15 OFF", a computer run-on of approx. 4 seconds is started.
However, it may also last for several minutes due to various functions (for example, on-board diagnosis (OBD), drive authorization system (DAS), thermal management).
Variants
The engine control variants, such as country and exhaust gas variants, are activated with the Diagnosis Assistance System (DAS) using the variant coding function.
Replacement of the CDI control unit is not necessary.
Assembly operations
Ensure before unplugging the plug on the CDI control unit that the ignition is switched off and computer run-on has ended. This is to prevent damage to the CDI control unit and save errors in the control units linked to the CAN.
| Wiring diagram for common rail diesel injection (CDI) control unit | N3/9 Engine plug | PE07.16-P-2101-97SAF | |
| N3/9 Vehicle plug | PE07.16-P-2101-97SAE |