The Hydraulic Control Unit (HCU) and the Controller Antilock Brake (CAB) used with this antilock brake system are combined (integrated) into one unit, which is called the Integrated Control Unit (ICU). The HCU controls the flow of brake fluid to the brakes using a series of valves and accumulators. A pump/motor is mounted on the HCU to supply build pressure to the brakes during an ABS stop.
The ICU is located on the driver's side of the vehicle, below the master cylinder.
For servicing, refer to Integrated Control Unit (ICU) procedure in this section.
Disconnect the pump/motor wiring harness from the CAB.
Remove the 4 bolts attaching the CAB to the HCU.
Remove the CAB from the HCU.
Removal & Installation
- Before servicing the vehicle, refer to the Precautions section.
- Using a brake pedal holder, depress the brake pedal past its first one inch of travel and hold it in this position. This will isolate the master cylinder from the brake hydraulic system and will not allow the brake fluid to drain out of the master cylinder reservoir.
- Disconnect negative (ground) cable from the battery and isolate the cable.
- Disconnect the positive cable from the battery, then remove the battery from the battery tray. There is one nut securing the clamp on the backside of the battery holding it in place.
- Remove the one nut and one bolt securing the air cleaner box in place, then disconnect the wiring harness connector at the air inlet sensor.
- Lift the air cleaner box upward enough to clear its grommeted alignment post, then move the air cleaner box forward just enough to access the battery tray mounting bolts.
Remove the 2 bolts, then the 2 nuts mounting the battery tray to its bracket. Remove the battery tray.
Disconnect the primary and secondary brake tubes from the master cylinder. Install plugs in the master cylinder outlet ports.
Disconnect the 24-way connector from the Controller Antilock Brake (CAB) mounted on the Integrated Control Unit (ICU) and move it out of the way. The connector is disconnected by pulling outward on the connector lock. This will unlock and raise the 24-way connector out of the socket on the CAB.
- Tag the brake tubes coming from the master cylinder as primary and secondary. This is done to avoid mix-up once the tubes are removed from the vehicle.
- Disconnect and remove the primary and secondary brake tubes coming from the master cylinder at the ICU Hydraulic Control Unit (HCU).
- Disconnect the brake tubes going to each individual brake at the HCU.
Remove the 3 bolts attaching the ICU to its mounting bracket.
- Remove the ICU from the vehicle.
- If the CAB and HCU must be separated, refer to the DISASSEMBLY procedure in this section.
- Install the ICU onto its mounting bracket.
Install the 3 bolts attaching the ICU to the mounting bracket. Tighten the 3 mounting bolts to a torque of 97 inch lbs. (11 Nm)
Install the four brake tubes going to the brakes into their respective outlet ports on the ICU HCU. Using a crow foot on a torque wrench, tighten the four brake tube nuts to a torque of 13 ft. lbs. (17 Nm).
NOTEWhen installing the brake tubes from the master cylinder on the HCU, the brake tube with the small tube nut is to be installed in the forward-most port on the HCU with the small end going toward the master cylinder secondary port.
- Install the primary and secondary brake tubes from the master cylinder onto the HCU. Do not completely tighten the primary and secondary tubes at this time.
- Connect the primary and secondary brake tubes to the master cylinder ports.
Using a crow foot on a torque wrench, tighten the primary and secondary brake tube nuts at both the master cylinder and HCU to a torque of 13 ft. lbs. (17 Nm).
WARNINGBefore installing the 24-way connector in the CAB, be sure the seal is properly installed in the connector.
Install the 24-way connector into the socket of the CAB as follows:
Position the 24-way connector in the socket of the CAB and carefully push it down as far as possible.
- When the connector is fully seated into the CAB socket, push the connector lock inward. This pulls the connector into the socket of the CAB and locks it in the installed position.
- Position the 24-way connector in the socket of the CAB and carefully push it down as far as possible.
Position the battery tray back in place. Install the two bolts, then the two nuts mounting the battery tray to its bracket. Tighten the two bolts and nuts to a torque of 135 inch lbs. (15 Nm).
- Reinstall the air cleaner box onto its grommeted alignment post.
- Install the one nut and one bolt securing the air cleaner box in place, then connect the wiring harness connector at the air inlet sensor.
- Install the battery and clamp it in place. Tighten the hold-down clamp bolt to a torque of 105 inch lbs. (12 Nm).
Connect the positive, then the negative (ground) cable on the battery.
NOTEThe ICU may need to be initialized using the DRBIII® scan tool, or equivalent, after ICU installation.
- Bleed the base brakes and ABS hydraulic systems..
- Fill the master cylinder to the proper fill level.
- Road test the vehicle to ensure proper operation of the base and antilock brake systems.