CDI control unit, component description

D07.16-1348-08

N3/30 CDI control unit

Location

The CDI control unit is located in the front right of the engine compartment.

Task

The CDI control unit operates in an electrical network of sensors and actuators to form the engine control system for engine 642.

The following systems and functions are controlled and coordinated by the CDI control unit according to input signals:

- fuel supply

- glow system control

- injected quantity control

- diagnosis and fault storage

- drive authorization system and immobilizer

- torque interface

- alternator interface

- exhaust gas recirculation (EGR)

- exhaust gas cleaning

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 The CDI control unit has an internal atmospheric pressure sensor.

Input and output signals

The following input signals are evaluated by the engine control system and respective output signals are issued:

 Direct input signals

 Direct output signals

 Drive LIN (LIN C1) signals

 Engine compartment CAN (CAN C) input signals

 Drive train sensor CAN (CAN I) input signals

 Engine compartment CAN output signals

 Drive train sensor CAN output signals

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Direct input signals

- circuit 15

- circuit 30

- circuit 31

- circuit 87

- hot film mass air flow sensor (B2/14)

- intake air temperature sensor (B2/14b1)

- rail pressure sensor (B4/17)

- boost pressure sensor (B5/8)

- camshaft sensor (B6/24)

- temperature sensor upstream of SCR catalytic converter (B16/12)

- coolant temperature sensor (B11/19)

- charge air temperature sensor (B17/15)

- temperature sensor upstream of catalytic converter (B19/18)

- temperature sensor upstream of diesel particulate filter (B19/19)

- temperature sensor upstream of turbocharger (B16/11)

- intake manifold pressure sensor (B28/19)

- diesel particulate filter differential pressure sensor (B28/20)

- accelerator pedal module (B37/3)

- fuel temperature sensor (B50/6)

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- left EKAS end position measurement sensor (B90/2)

- right EKAS end position measurement sensor (B90/3)

- exhaust back pressure sensor (B60/4)

- fuel filter heater with water level sensor (R53/1)

- oxygen sensor (B85/3)

- crankshaft sensor (B70/1)

- engine oil sensor (B40/8)

- actual value potentiometer for throttle valve (M16/48r1)

- actual value potentiometer for drive (M16/48r2)

- actual value potentiometer (sliding contact 1) (M16/48r3)

- actual value potentiometer (sliding contact 2) (M16/48r4)

- crash signal from AB Lowliner control unit (N2/14), except code (SH6) Thoraxbag for driver (in the backrest), except code (SH7) Thoraxbag for driver and front passenger (in the backrest), except code (SH9) Windowbag for driver and front passenger or AB Lowliner control unit (N2/15), with code (SH6) Thoraxbag for driver (in the backrest), with code (SH7) Thoraxbag for driver and front passenger (in the backrest), with code (SH9) Windowbag for driver and front passenger

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Direct output signals

- viscous fan (A27/2)

- actuator motor (M16/48m1) for the throttle flap positioner (M16/48)

- fuel pump relay (K40/9k3)

- circuit 50 starter relay (K40/9k5)

- engine timing circuit 87 relay (K40/9k7)

- intake port shutoff actuator (M72/2)

- vent line heater element (R39/4)

- accelerator pedal module

- exhaust gas recirculation positioner (Y27/17)

- pressure regulator valve (Y74/6)

- cylinder 1 injector (Y76/18)

- cylinder 2 injector (Y76/19)

- cylinder 3 injector (Y76/20)

- cylinder 4 injector (Y76/21)

- cylinder 5 injector (Y76/22)

- cylinder 6 injector (Y76/23)

- boost pressure actuator (Y77/8)

- quantity control valve (Y94/4)

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Drive LIN signals

- ALT with LIN bus (G2/7), communication

- glow output stage (N14/3), communication

Engine compartment-CAN input signals

Instrument cluster (A1)

- fuel reserve signal

AB Lowliner control unit, except code (SH6) Thoraxbag for driver (in the backrest), except code (SH7) Thoraxbag for driver and front passenger (in the backrest), except code (SH9) Windowbag for driver and front passenger or AB Lowliner control unit, with code (SH6) Thoraxbag for driver (in the backrest), with code (SH7) Thoraxbag for driver and front passenger (in the backrest), with code (SH9) Windowbag for driver and front passenger

- crash signal

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EGS control unit (N15/3) (with transmission 722.6) or control unit (Y3/8n4) (with transmission 722.9)

- 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

- limp-home mode EGS or fully integrated transmission control (VGS)

KLA control and operating unit (S98), with code (HH9) Regulated air conditioning (Tempmatic)

- request for fan nominal rotational speed of A/C 1 additional fan (M4/13) and A/C 2 additional fan (M4/14)

- A/C, status

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For EZS control unit (N73)

- start enable by the drive authorization system (FBS)

PSM control unit (N26/15) (with code (ED5) Parameterizable special module (PSM) or code (ED8) Preinstallation for a parameterizable special module (PSM))

- Working speed control, adaptation of the engine rpm

ESP control unit (N30/4)

- vehicle speed

- wheel speed signal

- brake recognition

- cruise control request, with code (MS1) CC

- engine torque request

ESM [EWM] control unit (N15/5)

- selector lever module position

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Drive train sensor CAN input signals

AdBlue® control unit (N141)

- injected reduction agent quantity for nitrogen oxides (NOX) reduction

- reduction agent quantity to be injected for cooling the AdBlue® injection valve

- fill level status in the AdBlue® tank

- diagnosis communication

NOx sensor control unit upstream of SCR CAT (A97/1) and NOx sensor control unit downstream of SCR CAT (A97/2)

- NOX concentration in the exhaust

- oxygen concentration in the exhaust

- diagnosis communication

Engine compartment CAN output signals

Instrument cluster

- messages in the display (A1p1)

- actuation of CHECK ENGINE indicator lamp (A1e41)

- circuit 61 signal

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EGS control unit (with transmission 722.6) or control unit (with transmission 722.9)

- requests for shift line displacement for CAT heating

Switching request

- engine torque

- engine coolant temperature

- engine speed

- engine load

- kickdown

- engine speed limitation active

- limp-home mode engine control

EZS control unit

- query regarding start enable by the FBS

PSM control unit () (with code (ED5) Parameterizable special module (PSM) or code (ED8) Preinstallation for a parameterizable special module (PSM))

- Working speed control, feedback

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 If the CDI control unit receives the signal "circuit 15 OFF" a processor run-on of approx. 4 seconds is started. However, it may also last for several minutes due to various functions (such as OBD, FBS).

Drive train sensor CAN output signals

AdBlue® control unit

- 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 communication

NOx sensor control unit upstream of SCR CAT and NOx sensor control unit downstream of SCR CAT

- diagnosis communication