P54.21-2675-11
N3/9 CDI control unit
Location
The CDI control unit is located in the right side of the engine compartment at the rear.
Task
The CDI control unit controls the following systems depending on the information received:
Fuel supply
Glow system control at engine start and during normal driving
Injection quantity control at engine start and during normal driving
Emission control system
Charge pressure control
Shutoff of the refrigerant compressor (A9)
Shut-off control
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The CDI control unit reads the signals from the following components:
Oil temperature sensor (B1)
Hot film mass air flow sensor (B2/5)
Intake air temperature sensor (B2/5b1)
Rail pressure sensor (/)B4/6
Charge pressure sensor (B5/1)
Camshaft Hall sensor (B6/1)
Coolant temperature sensor (B11/4)
Charge air temperature sensor (B17/8)
Pressure sensor downstream of air filter (B28/5)
Accelerator pedal sensor (B37)
Fuel temperature sensor (B50)
Exhaust back pressure sensor (B60)
Crankshaft position sensor (L5)
O2 sensor upstream of CAT (G3/2)
Oil level check switch (S43)
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Temperature sensor upstream of turbocharger (B19/11)
Temperature sensor downstream TWC (B19/8), on vehicles with code (474) Particulate filter
Pressure differential sensor (DPF) (B28/8), on vehicles with code (474) Particulate filter
Condensation sensor for fuel filter with heating element (B76/1), for vehicles with code (71o) Retrofitted heated fuel filter
In addition, the following sensor is installed in the CDI control unit:
Internal atmospheric pressure sensor, for altitude adaptation
The CDI control unit actuates the following components:
O2 sensor heater upstream of catalytic converter
Throttle valve actuator (M16/6)
Engine intake port shutoff (M55), up to 31.8.07
Starter relay (N10/1kL)
Fuel pump relay (N10/2kA)
Vent line heater element (R39/1)
Left exhaust gas recirculation controller (Y27/9)
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EGR cooler bypass flap switchover flap (Y85), in vehicles except for code (474) Particulate filter and with transmission 716.6
Pressure regulator valve (Y74)
Right boost pressure positioner (Y100/1)
Cylinder 1 fuel injector (Y76y1)
Cylinder 2 fuel injector (Y76y2)
Cylinder 3 fuel injector (Y76y3)
Cylinder 4 fuel injector (Y76y4)
Intake port shutoff switchover valve (Y83), from 1.9.07
Quantity control valve (Y94)
Communication via the Local Interconnect Network (LIN) takes place via the following components:
Alternator (G2)
Glow time output stage (N14/3), control of various flow functions and transmission of system faults
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The CDI control unit communicates with the following components via the Controller Area Network bus Class C (engine compartment) (CAN C):
Instrument cluster (A1), output of fault messages via the multifunction display (A1p13), actuation of the preglow indicator lamp (A1e16), actuation of the engine diagnosis indicator lamp (A1e58)
Electronic selector lever module control unit (N15/5), with transmission 722.6
EIS [EZS] control unit (N73)
ESP control unit (N47-5)
Steering column module (N80), cruise control control over the CC [TPM] switch (S40/4)
Central gateway control unit (N93)
EGS control unit (N15/3), with transmission 722.6
The CDI control unit has a fault memory, which can be read out using STAR DIAGNOSIS.