Shown: engine 651 from the front |
N3/9 | CDI control unit |
P07.16-3689-12
Location
The CDI control unit is located on the side on the air filter housing.
Tasks
The CDI control unit operates in an electrical network of sensors and actuators to form the engine management system for engine 651.
The following systems and functions are controlled and coordinated by the CDI control unit according to input signals:
Fuel supply
Control of glow system
Injection quantity control
Diagnosis and fault storage
Drive authorization system (FBS) and immobilizer
Heat management
Alternator interface
Exhaust gas recirculation
Exhaust treatment
ECO start/stop function
The CDI control unit has an internal atmospheric pressure sensor.
Input and output signals
The following input signals are evaluated by the engine management, which also issues the corresponding output signals:
Direct input signals
Direct output signals
LIN signals
CAN input signals
CAN output signals
Evaluation of input factors
The input factors that have been read in are evaluated by the integrated microprocessor and the affected components are then actuated.
Output of signals and actuation of components
Initial parameter are output over the following connections:
On vehicles up to model year 2016 one suspension CAN is present independently of the equipment. On vehicles as of model year 2016 one suspension CAN is present depending on equipment installed.
Variant 1
If the vehicle does not have equipment codes named in variant 2, one suspension CAN (CAN E) is present as up to model year 2016.
Variant 2
If the vehicle has one of the following equipment codes, there are two suspension CANs (suspension CAN 1 (CAN E1), suspension CAN 2 (CAN E2)):
Code 218 (Reversing camera)
Code 234 (Blind Spot Assist)
Code 459 (Steel suspension with adjustable damping)
Code 476 (Lane Keeping Assist)
Code 513 (Traffic Sign Assist)
Code 614 (Bi-xenon headlamps)
CODE 615 (Bi-xenon headlamp with active curve lights)
CODE 618 (Bi-xenon headlamp)
Code 621 (Intelligent Light System (left-hand traffic))
code 622 (Intelligent Light System)
Code 631 (Static LED headlamps for left-hand traffic system)
Code 632 (Static LED headlamps for right-hand traffic system)
CodeP44 (Parking Package)
Direct line
Drive-LIN (LIN C1)
Drive train CAN (CAN C)
suspension CAN (Variant 1) or suspension CAN 1 (Variant 2)
Drive train sensor CAN (CAN I)
The electronic ignition lock control unit (N73) is the central interface (Gateway) for exchange of function-relevant data for control units which are connected to the various Control Area Network (CAN) bus systems.
Input factors and initial parameters for the following assembly parts are read in or output over direct lines by the CDI control unit and are needed by the engine management:
Input factors over a direct line | Initial parameters over a direct line | Supplemental information |
Terminal 15 | – | – |
Circuit 30 (fused) | – | – |
Circuit 31 | – | – |
Circuit 87 | – | – |
Cylinder 3+4 knock sensor (A16/1) | – | – |
Cylinder 1+2 knock sensor (A16/4) | – | – |
Engine oil temperature sensor (B1) | – | – |
Hot film mass air flow sensor (B2/5) | – | – |
Intake air temperature sensor (B2/5b1) | – | – |
Rail pressure sensor (B4/6) | – | Fuel high-pressure circuit |
Boost pressure sensor (B5/1) | – | – |
Camshaft Hall sensor (B6/1) | – | – |
Coolant temperature sensor (B11/4) | – | – |
Temperature sensor upstream of catalytic converter (B16/22) | – | For code 927 (Emissions standard EU6) |
Charge air temperature sensor (B17/8) | – | – |
Temperature sensor upstream of diesel particulate filter (B19/9) | – | For code 474 (Diesel particulate filter) |
Temperature sensor upstream of ATL (B19/11) | – | – |
Pressure sensor downstream of air filter (B28/5) | – | – |
DPF differential pressure sensor (B28/8) | – | For code 474 (Diesel particulate filter) |
Accelerator pedal sensor (B37) - potentiometer 1 | – | – |
Accelerator pedal sensor - potentiometer 2 | Accelerator pedal sensor - potentiometer 2 | – |
Fuel temperature sensor (B50) | – | – |
Exhaust pressure sensor (B60) | – | – |
Crankshaft Hall sensor (B70) | – | – |
Fuel filter condensation sensor with heating element (B76/1) | Fuel filter condensation sensor with heating element (B76/1) | – |
Manual transmission main shifter shaft position sensor (B79/3) | – | with manual transmission |
– | Starter circuit 50 relay (F58kM) | – |
Circuit relay87M (F58kN) | Circuit relay87M (F58kN) | – |
Transmission cooling coolant circulation pump relay (F58kO) | – | |
Circuit 15 relay (F58kR) | – | – |
Oxygen sensor upstream of catalytic converter (G3/2) | – | – |
– | Fan motor (M4/7) | – |
Actual value potentiometer 1 (M16/6r1), throttle valve | Actuator motor (M16/6m1), throttle valve | – |
– | Intake port shutoff actuator motor (M55) | – |
Supplemental Restraint System control unit (N2/10) | – | – |
– | Fuel system control unit (N118) | – |
– | Vent line heater element (R39/1) | – |
– | Coolant thermostat heating element(R48) | – |
Clutch pedal switch (S40/3) | – | with manual transmission |
Start enable clutch pedal switch (S40/5) | – | For a manual transmission, with code B03 (ECO start/stop function), with code 494 (USA version) |
Oil level check switch (S43) | – | – |
Exhaust gas recirculation actuator actual value potentiometer (Y27/9r1) | Exhaust gas recirculation actuator motor (Y27/9m1) | – |
– | Pressure regulating valve (Y74) | – |
– | Cylinder 1 fuel injector (Y76/1) | – |
– | Cylinder 2 fuel injector (Y76/2) | – |
– | Cylinder 3 fuel injector (Y76/3) | – |
– | Cylinder 4 fuel injector (Y76/4) | – |
– | Boost pressure control pressure transducer (Y77/1) | – |
– | Radiator shutters actuator (Y84) | – |
– | Exhaust gas recirculation cooler bypass switchover valve (Y85) | – |
– | Quantity control valve (Y94) | – |
– | Engine oil pump valve (Y130) | – |
– | Oil spray nozzle shutoff valve (Y131) | – |
– | Coolant pump switchover valve (Y133) | – |
Input and initial parameters for the following assembly parts and control units are transmitted or received by the CDI control unit via the LIN or CAN and are needed by the engine management system:
Input factors via the drive-LIN (LIN C1) | Initial parameters via the drive-LIN (LIN C1) | Supplemental information |
Alternator (G2) | Alternator (G2) | – |
Glow output stage (N14/3) | Glow output stage (N14/3) | – |
Input factors via drive CAN (CAN C) | Output factors via drive CAN (CAN C) | Supplemental information |
Fuel system control unit (N118) | Fuel system control unit (N118) | – |
Dual-clutch transmission fully integrated transmission control unit (Y3/14n4) | Dual-clutch transmission fully integrated transmission control unit (Y3/14n4) | For code 429 (7G-DCT) |
Input factors via suspension CAN (CAN E) | Output factors via suspension CAN (CAN E) | Supplemental information |
Instrument cluster (A1) | Instrument cluster (A1) | – |
DISTRONIC electric controller unit (A89) (for code 239 (DISTRONIC PLUS)) | – | – |
Supplemental Restraint System control unit (N2/10) | – | – |
SAM control unit (N10) | – | via interior CAN (CAN B) and electronic ignition lock control unit (N73) |
AAC control and operating unit (N22/7) | – | via interior CAN (CAN B) and electronic ignition lock control unit (N73) |
Electronic Stability Program control unit (N30/4) | – | – |
Left front door control unit (N69/1) | – | via interior CAN (CAN B) and electronic ignition lock control unit (N73) |
Upper control panel control unit (N72/1) | – | Via battery sensor LIN (LIN B15), SAM control unit (N10), interior CAN (CAN B) and electronic ignition lock control unit (N73) |
Electronic ignition lock control unit (N73) | Electronic ignition lock control unit (N73) | – |
Steering column tube module control unit (N80) | – | – |
Diagnostics connection (X11/4) | Diagnostics connection (X11/4) | Via diagnostic CAN (CAN D) and electronic ignition lock control unit (N73) |
Input factors via drive train sensor CAN (CAN I) | Initial parameters via drive train sensor CAN (CAN I) | Supplemental information |
Powertrain control unit (N127) | Powertrain control unit (N127) | – |
Structure
The housing of the CDI control unit is made of diecast aluminum and the cover is made of corrosion-proof sheet steel. The CDI control unit is water proof and dust proof. The inside contains the 32-bit measuring and control electronics for the engine management.
Voltage supply
The CDI control unit is circuit 30 fused and also energized by circuit 87 when the ignition is switched on. In the operating voltage range it has both short-circuit protection and reversed polarity protection. Power is supplied through several pins connected in parallel to relieve the plug connections.
Ground connection
"Circuit 31" ground connection is connected through multiple ground lines to the firewall ground point (W11).
Assembly operations
Ensure before unplugging the connector on the CDI control unit that the ignition is switched off and processor 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.
Variants
The engine management variants, for example national versions and exhaust variants, are activated using XENTRY Diagnosis via the variant coding. Replacement of the CDI control unit is not necessary.