Function Check
Before commencing an electrical check as specified in the checking program (see section 5.4), first make a test drive - even if the malfunctions reported by the customer are probably minor. During the test drive, observe all legislation regarding road traffic safety.
Test procedure:
· Check Bowden cable position and correct if necessary; check engine system idle speed. (Section 5.8)
· Check that control unit / actuator is correctly installed
· Check wiring harness for corrosion
· Check the routing of the Bowden cable between the actuator and the throttle valve.
At no point may it be bent to a radius of less than 150 mm/6 in.
· Check adjustment of Bowden cable and readjust Bowden cable if necessary. (Section 5.8)
· Check brake lamps. Brake lamps must function.
Switch on cruise control
- Actuate tip switch "I" (control switch closed)
- Actuate tip switch "R" (control switch closed), if a speed value has been previously stored.
If, however, one of the following conditions is fulfilled, it will not be possible to switch on the cruise control:
- Tip switch "O" actuated (control switch open)
- Brake pedal actuated (brake lamp switch closed)
- Vehicle speed lower than 25 km/h (15 mph) or higher than 220 km/h (136 mph)
- Clutch pedal actuated (clutch switch open)
- "D" "3" "2" "1" signal from selector lever position switch (AT) not present.
Switch off or automatically quit cruise control
When the cruise control is switched off or has been quitted because of one of the above conditions, the servo motor returns to the 0 position. This means that the throttle valve is not actuated by the servo motor:
- Tip switch "O" of control switch open (control switch actuated)
- Brake lamp switch closed (service brakes actuated)
- Vehicle speed higher than 225 km/h (139 mph) or lower than 16 km/h (10 mph).
- Clutch switch open (clutch actuated)
or "D" "3" "2" "1" signal from selector lever position switch not present.
- Acceleration/deceleration greater than or equal to 4.5 m/s² (hard braking)
In case of a defect, an electro-magnetic safety clutch in the control unit/actuator ensures that the cruise control is decoupled.
The automatic transmission receives information about whether the cruise control is switched on or not.
Actuation of the tip switch can call up different cruise control functions:
I = Activate and maintain constant speed (fix)
When the "I" tip switch is actuated, the current vehicle speed is stored and maintained (fixed) by the cruise control.
R = Call up memory
When the "R" tip switch is actuated, the cruise control is activated and automatically returns the vehicle to the previously stored speed.
I = Accelerate and fix
Regular speed increase:
- Extended actuation (longer than 0.5 s) of tip switch "I" increases the vehicle speed. When tip switch "I" is released, the speed attained is automatically stored.
Increase speed by 2 km/h (1.25 mph):
- Brief actuation (not longer than 0.5 s) of tip switch "I" increases the vehicle speed by 2 km/h (1.25 mph). The speed thus attained is automatically stored.
R = Decelerate and fix
Regular reduction of speed:
- Extended actuation (longer than 0.5 s) of tip switch "R" decreases the vehicle speed. When tip switch "R" is released, the speed attained is automatically stored.
Decrease speed by 2 km/h (1.25 mph):
- Brief actuation (not longer than 0.5 s) of tip switch "R" decreases the vehicle speed by 2 km/h (1.25 mph). The speed thus attained is automatically stored.
O = Deactivate
When tip switch "O" is actuated, the cruise control is switched off.