ENGINE | 646 in MODEL 909 |
N07.08-2022-08
N3/21 | CDI control unit |
Location
The CDI control unit is located on the left in engine compartment.
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
– boost pressure control
– shutoff of the A/C compressor (Y38) (for vehicles with code (HH9) Regulated air conditioning, (Tempmatic))
- shutoff control
- European On-Board Diagnosis (EOBD)
The CDI control unit reads the signals from the following components:
– engine oil level sensor (B40/5)
– fuel pressure sensor (B4/6)
– boost pressure sensor (B5/1)
– rpm sensor (B6/19)
– coolant temperature sensor (B11)
– charge air temperature sensor (B17/9)
– intake manifold pressure sensor (B28/11)
– accelerator pedal module (B37/3)
– fuel temperature sensor (B50)
– fuel filter heater with condensation sensor (B76)
– crankshaft position sensor (L5/7)
- clutch pedal switch (S40/3)
– hot film MAF sensor (B2/5)
- catalytic converter temperature sensor (B19)
- temperature sensor upstream of diesel particulate filter (B19/12)
– diesel particulate filter differential pressure sensor (B28/8)
- exhaust back pressure sensor (B60)
– oxygen sensor (B85/2)
– AB control unit (A10), over a discrete line
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:
– fuel pump with fill level sensor (M18) over the fuel pump relay (K39) in the electrical center (A12)
– starter (M1) over the starter relay (K61) in the electrical center
– throttle valve actuator (M16/40)
– vent line heater element (R39/1)
– exhaust gas recirculation positioner (Y27/11)
– boost pressure control pressure transducer
– pressure regulating valve (Y74)
- cylinder 1 injector (Y761)
– cylinder 2 injector (Y76/2)
– cylinder 3 injector (Y76/3)
– cylinder 4 injector (Y76/4)
– boost pressure positioner (Y77/1)
– quantity control valve (Y94)
– glow plug (R14), glow plug (R15), glow plug (R16) and glow plug (R17) over the glow output stage (N14/2), controlling various glow functions
Communication via the drive LIN (LIN C1) takes place via the following components:
– alternator (G1)
The CDI control unit communicates via the engine CAN (CAN C) with the following components:
– Instrument cluster (P15)
– actuation of the preglow indicator lamp (P15e13)
– actuation of the indicator lamp EOBD (P15e17)
– outside temperature from the outside temperature sensor (B37)
– fuel level from the fuel fill level sensor (M18b1)
- climate control control and operating unit (A81) (for vehicles with code (HH9) Regulated air conditioning, (Tempmatic)):
– actuation of A/C compressor
– status of A/C compressor
– AB control unit, crash signal
– ESP control unit® (N30/4)
–brake lights switch status (S9/3)
– engine torque, raising/reducing request
– immobilizer control unit (A62), start enable from drive authorization system 3 (FBS 3)
The CDI control unit has a fault memory, which can be read out using a diagnostic system.