Geely EC715 2009, Workshop Manual

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6.6.2 Description and Operation
6.6.2.1 Description and Operation
This vehicle is equipped with anti-lock braking system (ABS)
and electronic brake-force distribution (EBD) system. In
addition to in the original brake system, the following
components are added:
Hydraulic Electronic Control Unit (HECU):
Note
Between hydraulic electronic control unit installation
bolts and bracket, there are rubber anti-vibration pads,
which are used to avoid the hydraulic electronic control
unit being affected by the vehicle vibration. The hydraulic
electronic control unit can not be disassembled, and
must be replaced as an assembly.
The hydraulic electronic control unit (HECU) controls system
function and detect faults. When the ignition switch is turned
on and there are no anti-lock braking system DTC codes, the
system provides power to the relay, so the battery positive
voltage is provided to the solenoid valve and pump. Hydraulic
electronic control unit (HECU) continuously tests the wheels
status to control wheel slip rate within a certain range so as to
maintain the vehicle stability. Hydraulic control piping uses
diagonal configuration, so that from the brake master cylinder
one channel fluid flows along the left front to right rear wheel,
the other flows from the right front to the left rear wheel. Two
channels are isolated, so that when one brake channel fails or
leaks, the other will make sure the continuous braking ability.
Hydraulic electronic control unit (HECU) includes the following
main components:
– ABS control module
– ABS Pump and Relay
–
Inlet Valve, each valve controls one wheel
– Outlet Valve, each valve controls one wheel
– Electromagnetic Coil Relay
Wheel Speed Sensor:
Wheel speed sensor is a Hall-type speed sensor. With the
wheels rotating, ABS control module uses the wheel speed
signal to calculate the wheel speed. Wheel speed sensor can
be individually replaced, but the signal plate (Gear) is fitted on
the axle and must be replaced together with the axle.
Brake Lamp Switch:
Press the brake pedal, the brake lamps are lit, while signals are
sent to the ABS brake control module.
ABS Warning Lamp:
Located on the instrument cluster, light to notify the driver the
ABS failure when the following events occurs:
– ABS control module detects the ABS system malfunction,
the instrument cluster receives a request for lighting the
ABS warning lamp through the CAN bus from the ABS
control module.
–
Instrument cluster carry out self-test in the beginning of
each ignition cycle, the indicator light about 3s.
– Instrument cluster detects the communication to the ABS
control module is lost.
EBD Warning Lamp:
Located on the instrument cluster, light to notify the driver EBD
failure. When the ABS Warning Lamp is lit, but EBD warning
lamp is not lit, the system will still have EBD function. When the
ABS Warning Lamp and EBD warning lamp are all lit, ABS and
EBD function all fail.
Self-diagnostic Test:
ABS control module performs a self-diagnostic test each time
the ignition switch is turned to on. As long as the ABS is
provided power and in a working status, it monitors the
performance. Once a fault is detected, it will trigger an alarm
until the fault disappears. ABS error code will be stored in
memory until being manually erased.
6-70 ABS / TCS / EBD / ESP Brake System
EC718/EC718RV EC715/EC715RV 10/2009