Brake Pressure Modulator Valve
Fig. 99 Modulator Replacement:
Refer to Fig. 99 when replacing modulator.
Removal/Installation
Removal:
- When removing the modulator unit or after removing it, be careful not to turn it upside-down or lean excessively.
- Do not spill brake fluid on the car; it may damage the paint; if brake fluid does contact the paint, wash it off immediately with water.
- Take care not to damage or deform the brake pipes during removal and installation.
- To prevent the brake fluid from flowing, plug and cover the hose ends and joints with a shop towel or equivalent material.
- Do not loosen the relief plug on the accumulator.
- Do not loosen the relief plug on the accumulator.
1. Disconnect the modulator unit 14P connector and pump motor 2P connector.
2. Remove the wire harness clip from the modulator bracket.
NOTE: When a new harness clip is installed after a wire harness or modulator unit replacement, adjust the harness clip to the dimensions shown below.
3. Remove the three 8 mm nuts, and remove the modulator unit from the bracket.
NOTE: When the pump motor or the modulator unit is replaced, bleed the high-pressure brake fluid first. Service and Repair
Installation:
1. Check whether the brake fluid level in the reservoir is at the MAX (upper) lever. If level is low, add fresh brake fluid to the MAX (upper) level.
2. Before installing the modulator unit on the car, be sure to bleed the air from the suction port in the modulator unit by leaning the modulator unit to one side slowly (about 45 degrees) as shown.
CAUTION: When installing the modulator unit, be careful not to turn it upside-down or lean excessively.
3. Install the modulator unit in the reverse order of removal.
NOTE: Check the letters stamped on the modulator body, and connect the brake pipes property. Tighten the flare nuts to 19 N.m (1.9 kgfm, 14 lbf-ft).
4. Start the engine and let it idle for a minute.
Check that:
- ABS indicator light is off.
- Brake fluid is not leaking from the brake pipe joints.
5. Stop the engine.
6. Check whether the brake fluid level in the reservoir is at the MAX (upper) level. If level is low add fresh fluid until the reservoir is refilled to the MAX (upper) level.
7. Bleed air from the brake system. Service and Repair
8. Check the ABS function using the ALB checker.
ABS Function Test
1. Raise the car off the ground and support it with safety stands ~see section 1).
2. Check that there is no brake drag.
3. Turn the ignition switch ON and confirm that the ABS indicator light comes on.
- If the ABS indicator light does not come on, follow the troubleshooting on page. Testing and Inspection
4. With the ignition switch OFF, disconnect the ABS inspection connector (6P) from the connector cover located under the glove box, and connect it to the ALB checker.
. Shift the transmission to neutral for manual transmission models, or to [P] position for automatic transmission models.
6. Start the engine and release the parking brake.
7. Turn the Mode Selector switch to "1".
8. Push the Start Test switch. The ABS indicator light should not come on while the Test in Progress light is on.
- If the ABS indicator light comes on, confirm the ABS code and perform the appropriate troubleshooting for the code.
NOTE: Do not turn the Mode Selector switch when the Test in Progress light is on. Damage to the ALB checker can result.
9. Turn the Mode Selector switch to "2".
10. Depress the brake pedal firmly and push the Start Test switch. The ABS indicator light should not come on while the Test in Progress light is on. There should be kickback on the brake pedal. Have the assistant check that the wheel controlled by the ABS can be rotated by hand when there is kickback on the brake pedal.
- If the ABS indicator light comes on, confirm the ABS code and perform the appropriate troubleshooting for the code.
- If the ABS indicator light does not come on and the wheel controlled by the ABS cannot be rotated, check the connection of the modulator wire harness connectors. If the connections are OK, replace the modulator unit.
NOTE: The kickback should occur approximately 20 seconds after the Start Test switch is pushed. The ABS can be checked with a brake tester, too, by checking the brake torque fluctuation of the wheel controlled by the ABS.
11. Turn the Mode Selector switch to "3", "4" and "5". Perform step 10 for each of the test mode positions.
Operation Sequence Simulated by Modes of ALB Checker
NOTE: The wheel sensors and sensor wire harnesses are not checked by the ALB checker.
Operation Sequence simulated by Modes of ABL Checker.
Mode 1: Sends the simulated driving signal 0 mph (0 km/h) 113 mph (180 km/h) 0 mph (0 km/h) of each wheel to the ABS control unit to check the system under the normal driving. There should be no kickback.
Mode 2: Sends the driving signal of each wheel, then sends the lock signal of the left-rear wheel to the ABS control unit to check the system under left-rear wheel lock. There should be kickback.
Mode 3: Sends the driving signal of each wheel, then sends the lock signal of the right-rear wheel to the ABS control unit to check the system under right-rear wheel lock. There should be kickback.
Mode 4: Sends the driving signal of each wheel, then sends the lock signal of the left-front wheel to the ABS control unit to check the system under left-front wheel lock. There should be kickback.
Mode 5: Sends the driving signal of each wheel, then sends the lock signal of the right-front wheel to the ABS control unit to check the system under right-front wheel lock. There should be kickback.
Inspection Points
If the ABS indicator light comes on and the system stops during the inspection, confirm the ABS code and perform the appropriate troubleshooting for the code. If there is no kickback in modes 2 through 5, and the ABS indicator light does not come on, the following items are probable causes:
- Pressure switch stuck ON
- Clogged or stuck solenoid outlet valve
- Modulator wire harness connectors improperly connected
Modulator Function Check
NOTE: This inspection determines whether the basic brake system continues to operate normally when the modulator unit fluid pressure is low.
CAUTION:
- This inspection is made by relieving the high-pressure fluid in the modulator unit and checking for brake operation. After inspection, be sure to add fresh brake fluid to the specified level of the reservoir, and start the engine to restore the ABS to its normal operating condition.
- Do not spill brake fluid on the car; it may damage the paint; if brake fluid does contact the paint, wash it off immediately with water.
- Do not reuse the drained brake fluid.
- Do not loosen the relief plug on the accumulator.
1. Remove the bleeder cap from the maintenance bleeder on the modulator unit.
2. Attach the wrench to the maintenance bleeder.
3. Connect a rubber tube of the appropriate diameter to the maintenance bleeder, and set the other end of the rubber tube in a suitable container.
4. While holding the rubber tube with your hand, slowly loosen the maintenance bleeder 1/8 to 1/4 turn to collect the brake fluid in the container.
CAUTION: Do not loosen the maintenance bleeder too much. The high-pressure brake fluid can burst out.
5. After the brake fluid stops flowing out, loosen the maintenance bleeder more to release the pressure completely.
6. Tighten the maintenance bleeder to the specified torque.
7 Raise the car off the ground and support with safety stands.
8. have an assistant depress the brake pedal firmly, and check that the wheels do not rotate.
9. Remove the cap and refill the reservoir to the MAX (upper) level with fresh brake fluid.
NOTE: Pour the brake fluid slowly so that it does not foam, and wait for a few minutes.
10. Start the engine and let it idle for a minute. Stop the engine.
11. Check the brake fluid level In the reservoir. It should be below the MAX (upper) level line. Refill the reservoir with fresh brake fluid to the MAX level line again.
12. After inspection, start the engine and make sure that the ABS indicator light goes off.