Hydraulic Control Unit (HCU)

The anti-lock hydraulic control unit (2C215) is located in the front of the engine compartment on the left frame rail. It consists of a valve body assembly, a pump and a motor assembly. During normal braking, fluid from the brake master cylinder (2140) enters the anti-lock hydraulic control unit through two inlet ports located at the top of the anti-lock hydraulic control unit. The fluid then passes through three normally open inlet valves, one to each wheel in the front and one line to the rear wheels. If the anti-lock brake electronic control module senses that a wheel is about to lock, the anti-lock brake electronic control module pulses the appropriate inlet valve which closes that valve. This prevents any more fluid from entering the affected brake. The anti-lock brake electronic control module then looks at that wheel again. If it is still decelerating, the anti-lock brake electronic control module pulses the normally closed outlet valve which decreases the pressure trapped in the line.

The valve body, the pump and the motor are not serviceable separately.

Item	Part Number	Description
1	2B112	Brake Pressure Control Valve Inlet Tube
2	2234	Tube
3	2C215	Anti-Lock Hydraulic Control Unit
4	W611633	Screw
5	2263	Front Brake Tube
6	2264	Front Brake Tube
7	2B523	Tube
8	N606703	Hydraulic Control Unit Mounting Bracket-to-Frame Bolt
9	N801107	U-Nut
A	—	Tighten to 34-46 Nm (25-33 Lb-Ft)

Hydraulic Schematic

Item	Part Number	Description
1	2005	Power Brake Booster
2	—	Outlet, Pressure Control Valve (Part of 2C215)
3	—	Outlet, Front Brake (Part of 2C215)
4	—	Outlet, Front Right (Part of 2C215)
5	—	Outlet, Front Left (Part of 2C215)
6	—	Outlet, Rear Axle (Part of 2C215)
7	2C215	Anti-Lock Hydraulic Control Unit
8	—	Pump Motor (Part of 2C215)
9	2140	Brake Master Cylinder