Chevrolet New Sail (2010). Manual — part 25

98

Parts Assumed

Malfunctions

Decoupled Dynamic Rear Proportioning

ABS Warning

Light

Brake Warning

Light

DDRP Mode

Right Front Sensor

Short-Circuited or

Open-Circuited

Connected -

Performance

Reduction

Left Front Sensor

Short-Circuited or

Open-Circuited

Connected -

Performance

Reduction

Right Rear Sensor

Short-Circuited or

Open-Circuited

Connected -

Performance

Reduction

Left Rear Sensor

Short-Circuited or

Open-Circuited

Connected -

Performance

Reduction

Two Sensors On The

Same Axle

Short-Circuited or

Open-Circuited

Connected Connected

Closed

A Front Axle Sensor

And A Rear Axle

Sensor

Short-Circuited or

Open-Circuited

Connected -

Performance

Reduction

Motor

Short-Circuited Against
The Ground - Low Side

Connected -

Performance

Reduction

Short-Circuited Against

The Ground - High Side

Connected -

Performance

Reduction

Short-Circuited Against

The Accumulator - Low

Side

Connected -

Performance

Reduction

Short-Circuited Against

The Accumulator - High

Side

- - -

Open-Circuited Motor Connected

-

Performance

Reduction

Motor Speed Loss

Connected

-

Performance

Reduction

Front Connected

Solenoid Valve

Short-Circuited or

Open-Circuited

Connected -

Performance

Reduction

Front Separate

Solenoid Valve

Short-Circuited or

Open-Circuited

Connected -

Performance

Reduction

Rear Connected

Solenoid Valve

Short-Circuited or

Open-Circuited

Connected -

Performance

Reduction

Rear Separate

Solenoid Valve

Short-Circuited or

Open-Circuited

Connected -

Performance

Reduction

System Relay

Open-Circuited (Cannot

Be Connected)

Connected -

Performance

Reduction

Short-Circuited

( Connected At All Time

And Cannot Be

Disconnected)

Connected Connected

-

Accumulator 2

(Motor)

Short-Circuited Against

The Ground

Connected -

Performance

Reduction

Open-Circuited -

-

Too

Low

Voltage

Grounding (Motor)

Short-Circuited or

Short-Circuited against

the Accumulator

Connected - Activated

Accumulator 1,

Electronic Brake

Control Module,

Solenoid Valve

Open-Circuited or

Short-Circuited against

the Ground

- -

Closed

Grounding,

Electronic Brake

Control Module,

Short-Circuited or

Short-Circuited against

the Accumulator

Connected Connected

Closed

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Chevrolet 2010 New Sail New Technical Training

- Learner's Manual

Solenoid Valve

Ignition

Open-Circuited or

Short-Circuited against

the Ground

Connected

ConnectedConne

cted

Closed

Brake Switch

Not Applicable

Connected

-

Activated

Serial

Communication

Open-Circuited or

Short-Circuited

Connected Connected Activated

5.5 Electronic Brake Control Module

（EBCM）

The electronic brake control module

（EBCM）carries out the following major functions to accomplish

effective braking and vehicle stability. In the DDRP

（decoupled dynamic rear proportioning）system, the power of

the rear maintaining solenoid valve is supplied by the ignition circuit.

If one of the following malfunctions occurs, the red brake warning light will be illuminated.

z Wheel speed sensor input malfunction.

z Detection of wheel slip.

z Control braking system in anti-lock control mode malfunction.

z Electrical system operation malfunction.

The electronic brake control module continuously detects the rotation speed of each wheel to determine

whether there is a wheel that starts to slip. Provided that a wheel slip is detected, the electronic brake control
module will require the control valve to move to an appropriate position in order to regulate the pressure of part of
the oil circuit or the entire oil circuit so that the wheel slip is prevented and the best braking effect is obtained. The
electronic brake control module continuously controls the pressure of each oil circuit until the slip disappears. The
electronic brake control module

（EBCM） also continuously monitors whether the operation of the anti-lock

braking system

（ABS） is proper. If a malfunction is detected, the electronic brake control module will shut down

the functions of the anti-lock braking system and illuminate the ABS warning light on the dashboard. In diagnostic
mode, the electronic brake control module also controls the display of the fault diagnosis code of the anti-lock
braking system.

5.6 Solenoid Valve Relay

The solenoid valve relay supplies power for the pump motor and the solenoid valve. The relay switch is

normally open, and must be closed during initialization. As long as the fault diagnosis code that requires the
switch to be open is not set, then the relay switch will remain closed at all times. If the fault diagnosis code is set
to require the relay to be open, then the accumulator voltage of the pump motor and the solenoid valve will be cut
off and the anti-lock braking system

（ABS） won’t function. The relay and the electronic brake control module

are incorporated together and cannot be repaired individually.

5.7 Wheel Speed Sensor and Toothed Ring

Each wheel has a wheel speed sensor, and the sensor transmits the rotation speed of the wheel to the

electronic brake control module in the form of a low AC voltage signal through an interface. This interface might
input a false wheel speed sensor signal, or a wheel speed sensor signal input that contains noise into the electronic
brake control module.

100

5.8 Anti-Lock Braking System

（ABS）Warning Light

The anti-lock braking system warning light is mounted in the instrument cluster and is illuminated when the

electronic brake control module detects any malfunction in the anti-lock braking system. The anti-lock braking
system

（ABS） warning light informs the driver that there is a malfunction resulting in the shut-down of the

anti-lock braking system. If only the anti-lock braking system warning light is illuminated, then normal braking
function with full brake assist will still work.

The conditions for activating the anti-lock braking system warning light are as follows:

z As stated above, when a malfunction is found in the anti-lock braking system, the anti-lock braking

system warning light will be illuminated.

z During a lamp test of the dashboard instrument cluster: the anti-lock braking system

（ABS） warning

light will be illuminated approximately for 3 seconds and then go out when the ignition switch is closed.

5.9 Brake Warning Light

The red brake warning light in the instrument cluster is illuminated to warn the driver that there is a

（are）

malfunction condition

（s） in the braking system and the braking effect is therefore reduced. When the hand brake

is pulled up, not completely loose, or the brake fluid level switch is closed

（the switch will be closed when the

brake fluid level in the fluid storage tank of the Master Cylinder is too low

）, the warning light will also be

illuminated. When the brake level switch is closed, the indicating fluid level is too low. At this point, the
malfunction

（s） must be repaired, otherwise the brake warning light won't go out. Some malfunctions in the

MGH-25 system will also illuminate the warning light to inform the driver that the DDRP

（decoupled dynamic

rear proportioning

） is shut down.

5.10 Rear Drum Brake

The drum brake assembly employs the design of a leading trailing shoe brake. The two brake shoes are

firmly compressed on the brake wheel cylinder piston by the lower return spring and the fixed anchor plate next to
it. When the brake pedal is pressed, the brake wheel cylinder piston moves the two brake shoes outwards to allow
them to touch the brake drums. When wheels are advancing, the front brake shoes will stretch out inside the brake
drums and generate energizing effort. When wheels are reversing, the rear brake shoes will generate self
energizing effort. The force from the brake shoes is passed to the anchor plate, and then passed to the axle flange
through the bottom plate. Adjustment is automatically carried out, and it happens every time the brake pedal is
pressed. The positions of used shoe plates shall not be exchanged, otherwise the self-adjustment function will
disable and the pedal stroke will be increased.

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Chevrolet 2010 New Sail New Technical Training

- Learner's Manual

1. Brake Drum
2. Torsion Spring
3. Adjusting Bracket
4. Brake Shoe Alignment Pin Nut Cap
5. Brake Shoe Locating Pin Spring
6. Brake Shoe
7. Regulating Stem
8. Brake Wheel Cylinder
9. Brake Wheel Cylinder Air Outlet Valve

10. Brake Wheel Cylinder Air Outlet Valve Nut Cap
11. Brake Backing Plate
12. Brake Shoe Inspection Hole
13. Dust Cap
14. Brake Wheel Cylinder Fixing Screw
15. Brake Shoe Alignment Pin
16. Brake Shoe Lower Tense Return Spring
17. Adjusting Bracket Spring
18. Brake Shoe Upper Tense Return Spring

5.11 Drum Brakes Adjustment

z For brake drum dismounting, please refer to "brake drum replacement".

z Screw a rear brake adjusting nut into the regulator assembly until adequate elongation is generated on the

brake drums.

z Employ a stop block of the parking brake bar to support the edge of the web plate. If necessary, loosen

the hand brake cable at the balance arm. Please refer to "parking brake bar assembly replacement".

z Mount brake drums.