Haima M3. Chassis System. Service Manual - part 8
Brake system 2F-56
II. For the faults without fault codes, repair it.
If the faults occur to the brake system, but ESP has no stored fault codes, and this fault is called as a fault
without fault codes. The fault without fault codes is generally caused by basic faults of brake system. E.g.:
Leakage of brake fluid (it may cause the softening of brake, overlong stroke of brake pedal, and even
serious failure of brake)
Application of poor brake fluid(the use of poor brake fluid will corrode the brake pipe and elements
inside ESP hydraulic control module, and lead to the serious failure of brake)
Existence of air in brake pipe (it may cause the softening of brake and even brake failure)
Blockage of brake pipe (it may cause the hardening of brake and even brake failure)
Excessive wears of brake disc (it may cause the softening of brake and overlong stroke of brake pedal)
Faults of booster (it may cause the hardening or softening of brake, overlong stroke of brake pedal and
even still brake failure seriously)
Wrong connection of brake pipe (it may cause the reduction of ESP performances, whipping and long
braking distance,etc. For the correct installation methods, please refer to the marks near to oil holes in
ESP hydraulic control module: MC1 stands for #1 master cylinder oil pipe; MC2 stands for #2 master
cylinder oil pipe; FL stands for left front wheel cylinder oil pipe; FR stands for right front wheel
cylinder oil pipe; RL stands for left rear wheel cylinder oil pipe; RR stands for right rear wheel
cylinder oil pipe)
Note: no power or power failure of ESP will lead to the constant illumination of ABS and ESP warning
lamps, but it has no fault codes. Suggestions for fault removal: check the corresponding parts as per the
fault symptoms, and remove the faults as per the vehicle maintenance manual.
III. Repair of occasional faults
In the electronic system, the instant poor contact may appear in the electric circuit and input/output signals,
thus it may cause the occasional faults. Sometimes, the fault causes will disappear automatically, so it’s not
easy to check these problems. In case of meeting the occasional faults, first read the historical fault codes
with a diagnostic unit, check the conditions related to fault codes, simulate the faults as per the following
modes, and check whether the faults are regenerated.
S/N
Possible causes
of faults
Simulated faults
Remarks
1
When the
vibration may be
a major cause
● Shake ESP ECU connector lightly
up, down, left or right.
● Shake ESP wire lightly up, down,
left or right.
● Shake the sensor lightly up, down,
left or right.
● Shake other moving parts(e.g. wheel
bearing) lightly.
If the wire is twisted off or broken
due to its excessive tension, it
must be renewed.
The wheel speed sensor wire will
become shortly open-
circuited/short-circuited due to
upward/downward movement of
suspension system during the
movement of vehicle. Therefore,
the actual driving test of vehicle
must be performed while
checking the sensor wires.
2
When the
temperature may
be a major cause
● Heat the parts with possible faults
with an air blower.
● Check them for cold welding with
cold spraying agent.
3
When the
excessive
electricity load
may be a major
● Turn on all the switches of electric
appliances, including the lamp and
wiper, to make the power supply of
vehicle work at high load.