Renault Scenic 3 Chassis. Manual - part 47
38C
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1
ANTI-LOCK BRAKING SYSTEM
Introduction
38C
The vehicle is fitted with a BOSCH 8.0. ABS system.
Depending on the vehicle equipment, the BOSCH 8.0
system consists of the ABS system only or the Anti-lock
Braking System in conjunction with the Electronic Sta-
bility Program (ESP).
I - DESCRIPTION OF THE ABS SYSTEM WITH
ELECTRONIC STABILITY PROGRAM
The ABS system / Electronic Stability Program compri-
ses:
- a brake servo assembly,
- a pump assembly comprising:
• a hydraulic pump,
• a pressure modulation unit (twelve solenoid valves),
• a computer,
• a pressure sensor,
- a steering wheel angle sensor built into the electric
power assisted steering,
- a combined yaw speed and transverse acceleration
sensor,
- four wheel speed sensors,
- aneElectronic stability program deactivation pressure
button.
II - PRINCIPLE OF OPERATION OF THE ABS
SYSTEM WITH ELECTRONIC STABILITY
PROGRAM
The reference status is calculated continuously from
wheel speed and steering wheel angle measurements.
The reference status represents the desired correct be-
haviour.
This reference status is compared to the actual status
of the vehicle from the yaw speed and transverse acce-
leration measurements.
Where there is a difference between the desired trajec-
tory and the actual trajectory, the appropriate wheel is
braked. In certain cases, the understeer monitoring
brakes two wheels at the same time. The torque gene-
rated sets the vehicle on the desired trajectory.
In some cases, the anti-skid control modifies the engine
torque.
III - ELECTRONIC STABILITY PROGRAM
OPERATION SPECIAL FEATURES
The ESP function can be disconnected via the switch
located on the dashboard.
This function can not be deactivated above a threshold
of approximately 50 km per hour.
This function is automatically reactivated when the ve-
hicle is switched on, or at speeds above approximately
50 km/h.
Equipment required
Diagnostic tool
IMPORTANT
After any operation on the ESP system, it is essen-
tial to confirm the repair with a road test and a check
with the Diagnostic tool (CLIP).