View of engine from front left |
N3/9 | CDI control unit |
P07.16-3775-82
Location
The CDI control unit is located on the engine.
Tasks
The CDI control unit performs the following tasks:
Controlling the engine basic functions
Reading in of signals
Evaluation of input factors
Output of signals and actuation of components
The CDI control unit also acts as the interface (gateway) between the three connected CAN bus systems.
Controlling the engine basic functions
Fuel supply
Glow system
Injection quantity control
Electronic accelerator
Diagnosis and fault storage
Drive authorization system and immobilizer
Heat management
Exhaust gas recirculation
Exhaust treatment
Torque coordination
Engine management Start-Stop function
Reading in of signals
Input factors are read in over the following connections:
Direct line
Drive-LIN (LIN C1)
Engine CAN (CAN C)
Drive train CAN (CAN C1)
Drive train sensor CAN (CAN I)
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:
Direct line
Drive train LIN
Engine CAN
Drive train CAN
Drive train sensor CAN
The powertrain control unit (N127) is the central interface (Gateway) for exchanging the function-relevant data of the control units that are connected to the various CAN bus systems.
Input parameters and initial parameters for the following components are read in or output over direct lines by the CDI control unit and are required by the engine management system:
Input factors over a direct line | Initial parameters over a direct line | Supplemental information |
Terminal 15 | – | – |
Circuit 30 (fused) | – | – |
Circuit 31 | – | – |
Terminal 87 | – | – |
Engine oil temperature sensor (B1) | – | – |
Left hot film mass air flow sensor (B2/6) | – | – |
Left intake air temperature sensor (B2/6b1) | – | – |
Right hot film mass air flow sensor (B2/7) | – | – |
Right intake air temperature sensor (B2/7b1) | – | – |
– high pressure fuel pressure sensor (B4/6) | – | Fuel high-pressure circuit |
Cylinder 1 combustion chamber pressure sensor (B4/34) | – | – |
Cylinder 2 combustion chamber pressure sensor (B4/35) | – | – |
Cylinder 3 combustion chamber pressure sensor (B4/36) | – | – |
Cylinder 4 combustion chamber pressure sensor (B4/37) | – | – |
Cylinder 5 combustion chamber pressure sensor (B4/38) | – | – |
Cylinder 6 combustion chamber pressure sensor (B4/39) | – | – |
Boost pressure sensor (B5/1) | – | – |
Camshaft Hall sensor (B6/1) | – | – |
Coolant temperature sensor (B11/4) | – | – |
Temperature sensor upstream of SCR catalytic converter (B16/15) | – | With CODE U77 (BLUETEC (SCR) diesel exhaust treatment) |
Charge air temperature sensor (B17/8) | – | – |
Temperature sensor upstream of catalytic converter (B19/7) | – | |
Temperature sensor upstream of diesel particulate filter (B19/9) | – | |
Temperature sensor upstream of ATL (B19/11) | – | – |
Pressure sensor downstream of air filter (B28/5) | – | – |
DPF differential pressure sensor (B28/8) | – | |
Accelerator pedal sensor (B37) | – | – |
Fuel temperature sensor (B50) | – | – |
Exhaust pressure sensor (B60) | – | – |
Crankshaft Hall sensor (B70) | – | – |
– | Starter circuit 50 relay (K40/8kH) | – |
– | Circuit 87M relay (K40/8kN) | – |
– | Engine compartment circuit 15 relay (K40/8kG) | – |
Oxygen sensor upstream of catalytic converter (G3/2) | Oxygen sensor upstream of catalytic converter (G3/2) | – |
Throttle valve actuator (M16/6) | Throttle valve actuator (M16/6) | – |
– | Intake port shutoff actuator motor (M55) | – |
Supplemental Restraint System control unit (N2/10) | – | – |
– | Fuel system control unit (N118) | – |
– | Vent line heater element (R39/1) | – |
Oil level check switch (S43) | – | – |
– | Exhaust gas recirculation actuator (Y27/9) | – |
– | 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) | – |
– | Cylinder 5 fuel injector (Y76/5) | – |
– | Cylinder 6 fuel injector (Y76/6) | – |
– | Boost pressure positioner (Y77/1) | – |
– | Exhaust gas recirculation cooler bypass switchover valve (Y85) | – |
– | Quantity control valve (Y94) | – |
– | Left switchable engine mount (Y123) and right switchable engine mount (Y123/1) | – |
– | Engine oil pump valve (Y130) | – |
– | Coolant pump switchover valve (Y133) | – |
Input parameters and initial parameters for the following components 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 train CAN (CAN C1) | Initial parameters via drive train CAN (CAN C1) | Supplemental information |
Fuel system control unit (N118) | Fuel system control unit (N118) | – |
Powertrain control unit (N127) | Powertrain control unit (N127) | – |
Fully integrated transmission control unit (Y3/8n4) | Fully integrated transmission control unit (Y3/8n4) | With code 427 (7G-TRONIC) or with code 421 (9G-TRONIC) |
Input factors over engine CAN (CAN C) | Initial parameters via engine CAN (CAN C) | Supplemental information |
Instrument cluster (A1) | Instrument cluster (A1) | Via user interface CAN (CAN HMI), electronic ignition lock control unit (N73), chassis FlexRay (Flex E) and powertrain control unit (N127) |
Supplemental Restraint System control unit (N2/10) | – | Via user interface CAN (CAN HMI), electronic ignition lock control unit (N73), chassis FlexRay (Flex E) and powertrain control unit (N127) |
Front SAM control unit (N10/6) | – | Via interior CAN (CAN B), electronic ignition lock control unit (N73), suspension FlexRay (Flex E) and powertrain control unit (N127) |
Climate control control unit (N22/1) | – | Via interior CAN (CAN B), electronic ignition lock control unit (N73), suspension FlexRay (Flex E) and powertrain control unit (N127) |
Electronic Stability Program control unit (N30/4) | – | Via suspension FlexRay (Flex E) and powertrain control unit (N127) |
AIRmatic control unit (N51/3) | – | Via suspension FlexRay (Flex E) and powertrain control unit (N127) |
Radar sensors control unit (N62/1) (with CODE P20 (Driving assistance package)) | – | Via suspension FlexRay (Flex E) and powertrain control unit (N127) |
Left front door control unit (N69/1) | – | Via interior CAN (CAN B), electronic ignition lock control unit (N73), suspension FlexRay (Flex E) and powertrain control unit (N127) |
Electronic ignition lock control unit (N73) | Electronic ignition lock control unit (N73) | Via suspension FlexRay (Flex E) and powertrain control unit (N127) |
Steering column tube module control unit (N80) | – | Via suspension FlexRay (Flex E) and powertrain control unit (N127) |
Powertrain control unit (N127) | Powertrain control unit (N127) | |
Diagnostic connector (X11/4) | Diagnostic connector (X11/4) | Via diagnostic CAN (CAN D), electronic ignition lock control unit (N73), suspension FlexRay (Flex E) and powertrain control unit (N127) |
Input factors via drive train sensor CAN (CAN I) | Initial parameters via drive train sensor CAN (CAN I) | Supplemental information |
NOx sensor control unit downstream of diesel particulate filter (N37/7) | NOx sensor control unit downstream of diesel particulate filter (N37/7) | With CODE U77 (BLUETEC (SCR) diesel exhaust treatment) |
NOx sensor control unit downstream of SCR catalytic converter (N37/8) | NOx sensor control unit downstream of SCR catalytic converter (N37/8) | With CODE U77 (BLUETEC (SCR) diesel exhaust treatment) |
AdBlue® control unit (N118/5) | AdBlue® control unit (N118/5) | With CODE U77 (BLUETEC (SCR) diesel exhaust treatment) |
Body
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.
The CDI control unit has an internal atmospheric pressure sensor.
Voltage supply
The CDI control unit is supplied with power by "circuit 30 fused" and, with the ignition on, by "circuit 87". In the operating voltage range it has both short-circuit protection and reversed polarity protection.
Power is supplied through several engaged parallel pins connected in parallel to relieve the electrical connections.
Computer power-down
When the CDI control unit receives the signal "circuit 15 OFF", a processor run-on of approx. 300 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 variants of the engine management, for exampled country and exhaust variants, are activated with XD over the variant coding.
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.