Starting, Function - GF07.10-D-1001HD
ENGINES 651.955/956/957 in MODEL 906
with CODE (XZ1) Model generation 1
with CODE (MZ0) Blue EFFICIENCY
Function requirements
- Start enable for DAS stage 3 (FBS 3)
- Circuit 87 ON
- Circuit 50 ON
- Engaged selector lever position "P" or "N", for vehicles with transmission 722.6
General
The CDI control unit (N3/28) actuates the following components to start the engine:
- Starter (M1)
- Pressure regulator valve (Y74/5)
- Cylinder 1 injector (Y76/14)
- Cylinder 2 injector (Y76/15)
- Cylinder 3 injector (Y76/16)
- Cylinder 4 injector (Y76/17)
- Quantity control valve (Y94/3)
- Fuel pump with fuel level sensor (M3/5) (for model 906)
The starter control in the CDI control unit takes on actuation and cutout of the starter.
For starting, the CDI control unit reads the following sensors and signals:
- Engine oil level sensor (B40/6), for the engine oil level
- Engine oil temperature sensor (B40/9), for the engine oil temperature
- Atmospheric pressure sensor, integrated in the CDI control unit, for detection of the atmospheric pressure
- Crankshaft sensor (L5/10), for the engine RPM
- Rail pressure sensor (B4/16), for the rail pressure
- Camshaft sensor (B6/23), for the camshaft position
- Coolant temperature sensor (B11/17), coolant temperature
- EGS control unit (N15/3) (for vehicles with transmission 722.6), selector lever position via engine compartment CAN (CAN C)
- EZS control unit (N73), "circuit 50 signal" via CAN C
The CDI control unit coordinates the injection sequence during starting based on the signals from the crankshaft sensor and the camshaft sensor.
The start quantity control in the CDI serves to calculate to a specific start quantity at an engine start independently of the position of the accelerator pedal module (B37/3) (for model 906).
Function sequence
The function sequence is subdivided into the following steps:
- Function sequence for start begin
- Function sequence for start end
Function sequence for start begin
For "circuit 15 ON" the CDI control unit receives the "circuit 50 signal" from the EZS control unit via CAN C.
The CDI control unit actuates the circuit 50 starter relay (K40/9k5) by means of a ground signal. The power contact on the starter relay circuit 50 closes and the solenoid switch for the starter is supplied with a voltage at "circuit 50" from "circuit 30".
If the CDI control unit detects that the engine is running via the crankshaft sensor and the message "circuit 61 ON" and that the start process has ended via the message "circuit 50 OFF", then the driver can regulate the injection quantity and thus the engine speed using the accelerator pedal module.
Function sequence for start end
Starter control is carried out automatically by the CDI control unit (touch start). If the starting procedure is initiated, "circuit 50 OFF" does not have any further influence on the starting procedure. When engine cranking speed has reached 400 to 700 RPM, or after a starting time of 5 to 40 s (depending on coolant temperature), the CDI control unit interrupts negative activation of the circuit 50 starter relay and thus terminates the starting procedure.
If there is a repeat start after the end of starting procedure, a cutoff period of about 1.5 to 3 s is applied. This takes place in order to prevent tracking of the turning starter drive pinion in the ring gear.
| CDI control unit, component description | N3/28 | GF07.16-D-6000HD |
| Component description for rail pressure sensor | B4/16 | GF07.04-D-6210HD |
| Component description for camshaft position sensor | B6/23 | GF07.04-D-6021HD |
| Component description for coolant temperature sensor | B11/17 | GF07.04-D-6040HD |
| Component description for an engine oil level sensor | B40/6 | GF18.40-D-4109HD |
| Component description for oil temperature sensor | B40/9 | GF18.30-D-2011HD |
| Component description for the crankshaft position sensor | L5/10 | GF07.04-D-6011HD |
| Component description for fuel pump | M3/3 With engine 651.940 | GF47.20-S-2000S |
| Component description for pressure regulating valve | Y74/5 | GF07.05-D-6020HD |
| Component description for fuel injectors | Y76/14, Y76/15, Y76/16, Y76/17 | GF07.03-D-6120HD |
| Component description for quantity control valve | Y94/3 | GF07.05-D-6010HD |