Inspection Using A Lexus Hand-Held Tester
ON-VEHICLE INSPECTION1. Check hydraulic brake booster fluid pressure change.
a. Inspect the battery positive voltage.
Battery positive voltage: 10 - 14 Volts
b. Turn the ignition switch OFF, depress the brake pedal more than 40 times.
HINT: When a pressure in power supply system is released, reaction force becomes light and stroke becomes longer.
c. Install Load Sensing Proportioning Valve (LSPV) gauge Special Service Tool (SST) 09709-29018 or equivalent, and brake pedal effort gauge, bleed air.
d. When booster does not operate:
- Depress the brake pedal and check fluid pressure.
At 245 N (55 lbs.):
- Front brake pressure: 2,700 kPa (391 psi) or more
- Rear brake pressure: 0 kPa (0 psi)
At 343 N (77 lbs.):
- Front brake pressure: 3,950 kPa (568 psi) or more
- Rear brake pressure: 0 kPa (0 psi)
e. When booster operates:
1) Turn the ignition switch ON and wait until the pump motor has stopped.
2) Depress the brake pedal and check fluid pressure.
At 49 N (11 lbs.):
Front brake pressure: 1,821 - 3,146 kPa (234 - 405 psi)
Rear brake pressure: 1,931 - 3,256 kPa (249 - 419 psi)
At 98 N (22 lbs.):
Front brake pressure: 4,967 - 6,291 kPa (639 - 809 psi)
Rear brake pressure: 3,587 - 4,911 kPa (462 - 632 psi)
At 147 N (33 lbs.):
Front brake pressure: 8,112 - 9,437 kPa (1,043 - 1,214 psi)
Rear brake pressure: 5,187 - 6,511 kPa (667 - 838 psi)
At 196 N (44 lbs.):
Front brake pressure: 11,147 - 12,471 kPa (1,434 - 1,604 psi)
Rear brake pressure: 6,789 - 8,112 kPa (873 - 1,044 psi)
2. Inspect hydraulic brake booster operation.
a. Inspect the battery positive voltage.
Battery positive voltage: 10 - 14 Volts
b. Turn the ignition switch OFF, depress the brake pedal more than 40 times.
HINT: When a pressure in power supply system is released, reaction force becomes light and stroke becomes longer.
c. Turn the ignition switch ON, check the pump motor operation noise.
- If the pump motor does not operate, check and replace the wire harness and pump motor.
d. Connect the Lexus hand-held tester.
1) Connect the Lexus hand-held tester to the DLC3.
2) Turn the ignition switch ON.
3) Select the "ACTIVE TEST" mode on the Lexus hand-held tester.
HINT: Please refer to the Lexus hand-held tester operator's manual for further details. To protect the solenoids, hand-held tester turns OFF automatically for 2 secs. after every solenoid has been turned ON.
e. Inspect the front ABS switching solenoid operation.
1) Select "SAT" and "SA2" on the Lexus hand-held tester.
2) With "SAT" and "SA2" turned ON simultaneously with the Lexus hand-held tester, depress the brake pedal with stable force and check that the pedal cannot be depressed.
HINT: To protect the solenoids, Lexus hand-held tester turns OFF automatically for 2 secs. after every solenoid has been turned ON.
- If the pedal can be depressed, replace the hydraulic brake booster.
NOTICE: When operating it continuously, set an interval of more than 20 seconds.
3) Once, release the brake pedal.
4) When the solenoids are OFF, after depressing the brake pedal again and check that the brake pedal can be depressed.
- If the pedal cannot be depressed, replace the hydraulic brake booster.
f. Inspect the front ABS solenoid operation.
1) Select "SFRH" and "SFLH" on the Lexus handheld tester.
2) With "SFRH" and "SFLH" turned ON simultaneously with the Lexus hand-held tester, depress the brake pedal with stable force and check that the brake pedal cannot be depressed.
HINT: To protect the solenoids, Lexus hand-held tester turns OFF automatically for 2 secs. after every solenoid has been turned ON.
- If the pedal can be depressed, replace the hydraulic brake booster.
3) Once, release the brake pedal when the solenoids are OFF, check that the brake pedal can be depressed.
- If the pedal cannot be depressed, replace the hydraulic brake booster.
4) Once, release the brake pedal. After depressing and holding the brake pedal with stable force, turn the SFRH and SFRR solenoids ON simultaneously.
HINT: To protect the solenoids, Lexus hand-held tester turns OFF automatically for 2 secs. after every solenoid has been turned ON.
5) When the solenoids are OFF, check that the brake pedal can be depressed.
- If the pedal cannot be depressed, replace the hydraulic brake booster.
6) Once, release the brake pedal. After depressing and holding the brake pedal with stable force, turn the SFLH and SFLR solenoids ON simultaneously.
HINT: To protect the solenoids, Lexus hand-held tester turns OFF automatically for 2 secs. after every solenoid has been turned ON.
7) Once release the brake pedal when the solenoids are OFF, check that the brake pedal can be depressed.
- If the pedal cannot be depressed, replace the hydraulic brake booster.
g. Jack up and support the vehicle.
h. Release the parking brake lever.
i. Inspect the rear ABS solenoid.
1) Select the "SRH" on the Lexus hand-held tester.
2) Turn the "SRH" ON with the Lexus hand-held tester and depress the brake pedal with stable force, and check that the right rear wheel by rotating it by hand.
HINT: To protect the solenoids, Lexus hand-held tester turns OFF automatically for 2 secs. after every solenoid has been turned ON.
When rotating the wheel fast, the fail-safe function is activated and judgement cannot be made properly. So rotate the wheel as slowly as possible.
- When solenoid is OFF, the wheel might stop temporarily. However if the wheel rotates again, the function works normally.
- If the rear wheels stop, replace the hydraulic brake booster.
3) Once, release the brake pedal and turn the "SRH" OFF, after depressing the brake pedal with stable force and check that the light rear wheels by stopping it by hand.
HINT: To protect the solenoids, Lexus hand-held tester turns OFF automatically for 2 secs. after every solenoid has been turned ON.
When rotating the wheel fast, the fail-safe function is activated and judgement cannot be made properly. So rotate the wheel as slowly as possible.
- If the rear wheels rotate, replace the hydraulic brake booster.
4) Depress the pedal with stable force, then turn the "SRH" and "SRR" ON simultaneously.
5) When the solenoids are ON, check that the right rear wheel can be rotated by hand.
j. Lower the vehicle.
k. Disconnect the Lexus hand-held tester.