ETS, ABS control mode, function - GF42.35-P-3000A

MODEL 210.08 /28 with CODE (212a) Electronic Traction System (ETS)

Braking process in normal mode

ABS control mode pressure increase

Each ABS control process starts with a normal braking process which the driver performs via the brake pedal. The ETS control module recognizes the braking process via the stop lamp switch and decelerated wheel speeds.

The brake pressure is first increased via the switchover solenoid valves (y18 and y19) and then at the front axle via the solenoid valves (y6 and y8) and at the rear axle via the solenoid valves (y10 and y12).

The pressure is reduced via the same solenoid valve during a normal braking process.

Fig 1: Identifying ETS, ABS Control Mode, Function Flow Chart

Courtesy of MERCEDES-BENZ OF NORTH AMERICA.

ABS control mode pressure holding

The control process or valve positions shown in the example relate to the VR brake.

If a wheel tends towards locking during the braking process, ABS prevents a further pressure increase. The ETS control module introduces the pressure holding phase from the slip values of the braked wheels.

The pressure holding phase is introduced by actuation of the solenoid valve (y8). The solenoid valves (y8 and y9) are closed in this control phase, as a result pressure in the VR brake caliper remains constant.

Fig 2: Identifying ETS, ABS Control Mode, Function Flow Chart (ABS Control Mode Pressure Holding)

Courtesy of MERCEDES-BENZ OF NORTH AMERICA.

ABS control mode pressure reduction

Fig 3: Identifying ETS, ABS Control Mode, Function Flow Chart (ABS Control Mode Pressure Reduction)

Courtesy of MERCEDES-BENZ OF NORTH AMERICA.

ABS control mode pressure reduction

The control process or valve positions shown in the example relate to the VR brake.

The ETS control module introduces the pressure reduction phase from the slip values of the braked wheels.

The pressure reduction phase is introduced by actuation (opening) of the solenoid valve (y9). The solenoid valve (y8) remains actuated (closed) in this control phase.

During the pressure reduction phase, brake fluid flows back into the high pressure/return pump (p1) via the accumulator (11). From there the high pressure/return pump in the front axle brake circuit delivers brake fluid back to the master brake cylinder against the existing pressure. A silencer (10) is fitted for each brake circuit to reduce delivery noise

	ETS control mode, function		GF42.35-P-3500A
	Location/purpose/design/function of ETS hydraulic unit		GF42.35-P-4000A
	Location/purpose/design/function of ETS control module		GF42.35-P-4500A