DDRP (De-coupled Dynamic Rear Proportioning) is proportioning system to maintain vehicle stability during braking. In normal braking condition, equal wheel speed should be maintained for efficient and balanced braking. In hard braking conditions, a vehicle requires relatively less brake force at the rear wheel due to vehicle's weight transfer to the front. DDRP maintains desired brake pressure to the rear wheel by using the ABS rear inlet and outlet valve in order to provide efficient braking and vehicle stability. In the DDRP system, power to the rear hold valve solenoid is provided from the ignition. If the following fault conditions are existing. The red brake warning lamp will be illuminated.

The EBCM performs the following primary functions in order to provide efficient braking and vehicle stability. in the DDRP system, power to the rear hold valve solenoid is provided from the ignition. If the following fault conditions are existing. The red brake warning lamp will be illuminated.

The EBCM continuously checks the speed of each wheel to determine if any wheel is beginning to slip. If any wheel slip tendency is detected, the EBCM commands appropriate valve positions to modulate brake fluid pressure in some or all of the hydraulic circuits to prevent wheel slip and provide optimum braking. The EBCM continues to control pressure in individual hydraulic circuits until a slipping tendency is no longer present. Also the EBCM continuously monitors the ABS for proper operation. If the EBCM detects an error, it can disable the ABS function and turn on the ABS Warning Lamp in the instrument cluster. The EBCM also controls the display of the ABS DTCs (Diagnostic Trouble Codes) while in diagnostic mode.

The solenoid relay, provides power to the pump motor and solenoids. The switch in the relay is normally open, but is commanded to close during initialization. The relay switch will remain closed for the remainder of the drive cycle as long as no DTCs (Diagnostic Trouble Codes) set which required the switch to open. If a DTC sets which requires the relay to be commanded off, battery voltage will be removed from the pump motor and solenoids for the remainder of the current drive cycle and ABS cannot function. The relay is an integral part of the EBCM and cannot be serviced separately.

A wheel speed sensor is present at each wheel. The sensors transmit wheel speed information to the EBCM by means of a small AC voltage. This voltage is generated by magnetic induction caused by passing a toothed sensor ring past a stationary sensor. The magnitude and frequency of the AC voltage are proportional to the speed of the wheel and both will increase with increasing speed. The signal is transmitted to the EBCM through interface that can cause false or noisy wheel speed sensor input to the EBCM. Two different types of wheel speed sensors are used for DBC 7 system.

The ABS warning lamp is located in the instrument cluster and will illuminate if a malfunction in the ABS is detected by the EBCM. The ABS warning lamp informs the driver that a condition exists which results in turning off the antilock brake function. If only the ABS warning lamp is on, normal braking with full power assist is available.

Conditions for the ABS warning lamp to turn on are as follows.

The red brake warning lamp is in the instrument cluster and will illuminate to warn the driver of conditions in the brake system, which may result in reduced braking ability. The lamp will illuminate when the parking brake is applied or not fully released, or if the brake fluid level switch is closed (closed is when the brake fluid is low in the master cylinder reservoir). When the brake fluid level switch is closed (low condition) a brake warning lamp will stay illuminated until the condition has been repaired. Also some failure modes in DBC 7 system will illuminate the lamp to let the drivers know DDRP (De-coupled Dynamic Rear Proportioning) is disabled.