Component description for a CDI control unit

P07.08-2098-02

Illustrated on model 203.0

N3/9 CDI control unit

Location

The CDI control unit is installed in the electrical systems box in the engine compartment.

Task

The CDI control unit controls the following systems according to the input information:

 Fuel supply

 Control of the glow system during engine start and during driving mode

 Control of the injection quantities during engine start and during driving mode

 Emission control system

 Charge pressure control

 Shutoff of the coolant compressor (A9)

 Shutoff control

The CDI control unit reads the signals from the following components:

 Oil temperature sensor (B1)

 Left hot film mass air flow sensor (B2/6)

 Intake air temperature sensor (B2/6b1)

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 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)

 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 Hall sensor (B70)

 O2 sensor upstream of TWC (G3/2)

 Oil level indicator switch (S43)

 Temperature sensor upstream TWC (B19/7) on models with code (474) particulate filter

 Temperature sensor upstream diesel particles (B19/9) on models with code (474) particulate filter

 Differential pressure sensor (DPF) (B28/8) on models with code (474) particulate filter

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In addition, the following sensors are built into the CDI control unit:

 Internal temperature sensor, for control unit temperature

 Internal atmospheric pressure sensor, for altitude adaptation

The CDI control unit actuates the following components:

 Heater for O2 sensor

 Throttle valve actuator (M16/6)

 Inlet port shutoff motor (M55)

 Starter relay (N10/1kS)

 Fuel pump relay (N10/2kA)

 Vent line heater element(R39/1)

 Left exhaust gas recirculation positioner (Y27/9)

 Pressure control valve (Y74)

 Charge pressure positioner(Y77/1)

 Fuel injector cylinder 1 (Y76y1)

 Fuel injector cylinder 2 (Y76y2)

 Fuel injector cylinder 3 (Y76y3)

 Fuel injector cylinder 4 (Y76y4)

 Fuel injector cylinder 5 (Y76y5)

 Fuel injector cylinder 6 (Y76y6)

 Quantity control valve (Y94)

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With the following components, communication takes place via a Local Interconnect Network (LIN):

 Alternator (G2)

 Glow output stage (N14/3), control of various glow functions and transmission of system faults

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 multifunction display (A1p13), actuation of engine diagnosis malfunction indicator lamp (A1e58)

 Electronic selector lever module control unit (N15/5) with transmission 722.9

 ESP and BAS control unit (N47-5)

 for EIS control unit (N73)

 Steering column module (N80), cruise control controlling over the CC [TPM] with variable speed limiter switch (S40/4) (model 203) or TPM switch (S40/4) (model 209)

 Fully integrated transmission control control unit (Y3/8n4), with transmission 722.9

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The CDI control unit has a fault memory, which can be output via STAR DIAGNOSIS.