ICU (Integrated Control Unit): Removal

2004 Toyota Matrix XR, FWD, StandardSECTION Removal
WARNING: This page is about a different car, the 2004 Chrysler Pacifica. However, it is still accessible from the selected car via links, so may be relevant.
  1. Disconnect negative (-) battery cable from battery post and isolate.
    CAUTION: Vacuum in power brake booster must be pumped down (removed) before removing master cylinder from power brake booster. This is necessary to prevent power brake booster from sucking in any contamination as master cylinder is removed. This can be done simply by pumping brake pedal, with vehicle's engine not running, until a firm feeling brake pedal is achieved.
  2. With engine, not running, pump brake pedal until a firm pedal is achieved (4-5 strokes).
  3. Remove nuts fastening coolant recovery bottle in place and reposition bottle with hoses attached out of way. (Refer to COOLANT RECOVERY PRESS CONTAINER ).
    CAUTION: Before removing master cylinder from power brake vacuum booster, master cylinder and vacuum booster must be thoroughly cleaned. This must be done to prevent dirt particles from falling into power brake vacuum booster.
  4. Thoroughly clean all surfaces of brake fluid reservoir and master cylinder, paying special attention to area where master cylinder attaches to power brake booster. Use only Mopar(R) Brake Parts Cleaner or equivalent.
  5. Disconnect wiring harness connector from brake fluid level switch in master cylinder brake fluid reservoir (Fig 1 ).
    Fig 1: Identifying Brake Fluid Level Switch Connector
    G03571352Courtesy of DAIMLERCHRYSLER CORP.
  6. Disconnect primary and secondary brake tubes coming from master cylinder at ABS ICU (Fig 2 ). Cap off brake tubes and install sealing plugs in open brake tube outlet ports of ICU.
    Fig 2: Disconnecting Primary And Secondary Brake Tubes
    G03571353Courtesy of DAIMLERCHRYSLER CORP.
  7. Remove two nuts attaching master cylinder to power brake booster (Fig 3 ).
  8. Slide master cylinder straight out of power brake booster.
    CAUTION: Seal on rear of master cylinder is used to create seal for holding vacuum in power brake vacuum booster. Vacuum seal on master cylinder MUST be replaced whenever master cylinder is removed from power brake vacuum booster.
  9. Remove vacuum seal located on mounting flange of master cylinder. Vacuum seal is removed from master cylinder by carefully  pulling it off rear of master cylinder. Do not attempt to pry seal off master cylinder by inserting a sharp tool between seal and master cylinder casting. 
  10. Disconnect four chassis brake tubes at ABS ICU (Fig 4 ). Cap off brake tubes and install sealing plugs in open brake tube outlet ports of ICU.
    Fig 3: Identifying Master Cylinder Mounting Components
    G03571354Courtesy of DAIMLERCHRYSLER CORP.
RENDER: 1.0x

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When to See a Mechanic

Stop DIY work and contact a certified mechanic immediately if any of the following apply:

  • You smell fuel, burning insulation, or see smoke.
  • Brakes feel soft, pull hard to one side, or make grinding noises.
  • The engine overheats, stalls repeatedly, or misfires under load.
  • You are missing required tools, torque specs, or safe lifting equipment.
  • You are not confident in the next step or safety outcome.