Cruise Control (FGR)
OPERATIONThe Cruise Control (FGR) is activated by the cruise control switch. The control system uses the road speed signal (speed-A) from the instrument cluster. The five different switch positions of the FGR switch are detected by the Electronic Throttle Control (EML) control unit by way of different voltage values. In addition to the five different switch positions, the EML control unit also detects "interruption" or "short to ground". The EML control unit assigns the following values to the different voltage values:
Set/Accelerate
In the function "set/accelerate", the cruise control system accelerates until the FGR switch is released. After releasing the FGR switch, the cruise control system maintains the speed constant to the achieved value plus .3 - 1.2 mph (0.5 to 2 km/h). The achieved value plus .3 - 1.2 mph (0.5 to 2 km/h) forms the nominal FGR speed value which is stored in the EML control unit. After ignition "OFF" the stored nominal FGR speed value is 0 mph-km/h once again.
Set/Decelerate
In the function "set/decelerate", the cruise control system reduces the speed until the FGR switch is released. After releasing the FGR switch, the cruise control system maintains the speed constant to the achieved value minus .3 - 1.2 mph (0.5 to 2 km/h). The achieved value minus .3 - 1.2 mph (0.5 to 2 km/h) forms the nominal FGR speed which is stored in the EML control unit.
Call Function
In the "call" function, the cruise control systems sets the road speed to the nominal FGR speed value which is stored in the EML control unit.
OFF Function
In the "OFF" function, the cruise control system cuts out smoothly. Cruise control is also deactivated or cannot be activated when one of the following cut-out conditions occurs.
- Brake is operated
- Clutch is operated (manual transmission)
- Gear disengaged without clutch (manual transmission)
- Gear selector lever set in P or N or detected by control unit as engaged (automatic transmission)
- Control unit detects road speed <22mph (36 km/h)
- Actual speed is greater by 10 mph (16 km/h) or less by 8 km/h than the nominal FGR speed value
- Vehicle acceleration greater than 1.5 m/s*s (speed increase greater than 3.3 mph (5.4 km/h) per second)
- External safety path sends ground and therefore Idle Signal (LL) to DME and EML systems
If cruise control is deactivated by one of these conditions, it cannot be reactivated before the FGR switch has been set to "neutral position" and the cut-out condition no longer exists. This ensures that cruise control remains deactivated in the case of a permanently defective FGR switch (faulty control voltage).
Neutral Position
In "neutral position" (FGR switch not operated). the last activated function of the cruise control system is retained.
All functions are activated by briefly pressing the switch. In the case of the set/accelerate" and "set/decelerate" functions, by briefly pressing the switch (less than approx. 0.5 s) the speed is increased/decreased by .6 mph (1 km/h) each time the switch is pressed when "set/accelerate" or "set/decelerate" is already active.