Variable Speed Limiter, function - GF30.30-P-3001LEA
ENGINE 156, 273, 275 in MODEL 216 as of Model Year 09/AEJ 08 with CODE (219) Distronic (DTR)
ENGINE 156, 272, 273, 275, 642, 629 in MODEL 221 as of Model Year 09/AEJ 08 with CODE (219) Distronic (DTR)
View of instrument cluster (A1) with Variable Speed Limiter activated
Function requirements of Variable Speed Limiter in general
- Circuit 61 ON (engine running)
- CC [TPM] (cruise control) coded in central gateway control unit (N93)
- Electronic Stability Program (ESP) not deactivated
- Vehicle speed > 30 km/h
- Parking brake not applied
- Gear range "D" engaged
- CC push button (S40/4) in variable speed limiter position LIM indicator lamp (LIMI TER) is lit
Variable Speed Limiter, general
The Variable Speed Limiter (also called the variable speed limiter or SPEEDTRONIC) is an additional function of the Distronic, which is integrated in the ESP control unit (N47-5).
The Variable Speed Limiter allows the driver to set his/her own maximum speed, in a range from 30 km/h up to vehicle maximum speed.
The signals from the CC push button switch are detected by the steering column tube module (N80) and transmitted to the ESP control unit over the chassis CAN (CAN E).
The ESP control unit sends the selected maximum speed over the chassis CAN and central CAN (CAN F) to the instrument cluster.
The ESP control unit sends the accelerate/decelerate requests (for intervention by the engine control) over the chassis CAN to the CDI control unit (N3/9) or ME-SFI control unit (N3/10).
The ESP control unit sends a shift request for the automatic transmission over the chassis CAN and drive train CAN (CAN C) to the ETC control unit (N15/3) or electric controller unit (VGS) (Y3/8).
Variable Speed Limiter, function sequence
The function sequence is described in the following steps:
- Maximum speed function sequence
- Activation function sequence
- Deactivation function sequence
Maximum speed function sequence
The engine performance is reduced if the vehicle approaches the set maximum speed.
If this is inadequate, the service brake is actuated proportionately and if necessary, the automatic transmission shifts to a lower gear so that the set maximum speed is not exceeded (e.g. in case of steep declivity).
Activation function sequence
Pulling or moving the CC [TPM] push button switch up or down activates the Variable Speed Limiter. At this time, the current vehicle speed is set as the maximum speed and moving the CC [TPM] push button switch increases or decreases it.
The CC [TPM] switch can be moved up or down to increase or reduce the maximum speed in 1 km/h or 10 km/h increments (two settings).
If the Variable Speed Limiter is activated at a speed of <30 km/h, the maximum speed is automatically set to 30 km/h.
When the Variable Speed Limiter is activated, the segments in the speedometer arc are illuminated from the beginning of the scale up to the set maximum speed. The set maximum speed is marked with an orange-colored triangle.
If a switchover to the Variable Speed Limiter takes place at the CC [TPM] push button switch, DISTRONIC is simultaneously deactivated.
Deactivation function sequence
The Variable Speed Limiter is deactivated by:
- Moving the CC [TPM] push button to the "OFF" position
- switching over to DISTRONIC LIM indicator lamp off
- operating the service brakes
- Operating the parking brake
- Engaging gear range "N" or "R"
- ESP control intervention function
- deactivating ESP
- Kickdown (accelerator pedal pressed by > 90% and vehicle speed <20 km/h away from selected maximum speed)
- Vehicle speed <30 km/h
- Circuit 61 OFF (engine off)
| ESP control unit, component description | N47-5 | GF42.45-P-5118LE |