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 

 

99 

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.     

 

101 

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.