Basic braking mode
The DBC7 ABS main braking mode used in this vehicle is a diagonally distributed system. In this system, one circuit of the master cylinder supplies pressure to the right front and left rear brakes, the other circuit supplies pressure to the left front and right rear brakes.
All hydraulic modulator valves are in their normal, non-energized condition.
Master brake cylinder. ABS braking mode - supply
In the hold or depressurize mode, the EMU determines that the wheel lock has been reduced. EMUT increases the voltage of the corresponding wheel by applying pressure to the brake master cylinder. The intake valve opens and the exhaust valve closes, allowing pressure from the master cylinder to be applied to the wheel.
Master brake cylinder. ABS braking mode - hold
If the EMU detects wheel lockup, the EMU closes the intake valve and keeps the exhaust valve closed in the brake pressure modulator valve to isolate the system. This keeps the pressure on the brake stable, so the hydraulic pressure neither increases nor decreases.
Master brake cylinder. ABS braking mode - reset
If, in pressure hold mode, the CMTF still detects wheel lockup, the CMFM reduces the pressure of the corresponding wheel. The intake valve remains closed while the exhaust valve opens. Excess fluid/pressure is temporarily stored in a reservoir in the brake pressure modulator valve until the pump can return fluid to the brake master cylinder reservoir.
Master brake cylinder. DDRP
(separate dynamic metered distribution to the rear wheels)
DDRP (separate dynamic metered distribution to the rear wheels) is a system for maintaining vehicle stability during braking. Under normal braking conditions, the same wheel speed must be maintained for effective and balanced braking. During emergency braking, the vehicle requires relatively less braking force on the rear wheel as the weight of the vehicle is shifted forward. DDRP maintains proper braking pressure at the rear wheel by using the rear ABS intake and exhaust valves to provide efficient braking and vehicle stability. The DDRP system supplies power to the rear valve from the ignition.
If the following faults occur, the red brake warning light comes on.
- Two wheel speed sensors on the same axle do not work.
- Rear intake solenoid not working.
- Battery short circuit 2 (motor input) to the mass. Open or shorted battery 1 (EMUT input) to the mass.
- Open or short circuit of the electric motor to the battery.
- Open or short circuit of the EMUT to the battery.
- Ignition open or short to ground.
DDRP system malfunctions
EMUT provides effective braking and vehicle stability. The DDRP system supplies power to the rear valve from the ignition. If the following faults occur, the red brake warning light comes on.
|
Detail |
Suspected malfunction |
DDRP |
||
|
ABS warning light |
Brake warning light |
D-DRP Status |
||
|
Right front wheel sensor |
Short circuit or open circuit |
On |
- |
Partial operability |
|
Left front wheel sensor |
Short circuit or open circuit |
On |
- |
Partial operability |
|
Right rear wheel sensor |
Short circuit or open circuit |
On |
- |
Partial operability |
|
Left rear wheel sensor |
Short circuit or open circuit |
On |
- |
Partial operability |
|
Two sensors on one axis |
Short circuit or open circuit |
On |
On |
Shutdown |
|
One front and one rear sensors |
Short circuit or open circuit |
On |
- |
Partial operability |
|
electric motor |
Short circuit to ground - low voltage circuit |
On |
- |
Partial operability |
|
Short circuit to ground - high voltage circuit |
On |
- |
Partial operability |
|
|
Short circuit to battery - low voltage circuit |
On |
- |
Partial operability |
|
|
Short circuit to battery - high voltage circuit |
- |
- |
No |
|
|
Open motor circuit |
On |
- |
Partial operability |
|
|
Stopping the motor |
On |
- |
Partial operability |
|
|
Front Wheel Engagement Solenoids |
Short circuit or open circuit |
On |
- |
Partial operability |
|
Front wheel release solenoids |
Short circuit or open circuit |
On |
- |
Partial operability |
|
Rear wheel grip solenoids |
Short circuit or open circuit |
On |
- |
Partial operability |
|
Rear Wheel Release Solenoids |
Short circuit or open circuit |
On |
On |
Partial operability |
|
System relay |
cliff (inability to turn on) |
On |
- |
Partial operability |
|
Short circuit (inability to turn off) |
- |
- |
No |
|
|
Battery 2 (motor) |
Short circuit to ground |
On |
On |
Partial operability |
|
Gap |
- |
- |
Low voltage |
|
|
«Weight» (Motor) |
Open or short to battery |
On |
- |
Inclusion |
|
Battery 1 (ECU, solenoids) |
Open or short to ground |
On |
On |
Shutdown |
|
«Weight» (ECU, solenoids) |
Open or short to battery |
On |
On |
Shutdown |
|
Ignition |
Open or short to ground |
On |
On |
Shutdown |
|
brake switch |
Not applicable |
- |
- |
Inclusion |
|
serial communication |
Open or short circuit |
On |
On |
Inclusion |