Montero XLS 4WD V6-3.5L SOHC (2001)
Part 2 of 2
CIRCUIT OPERATION
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The ABS-ECU controls the buzzer by turning the power transistor in the control unit ON and OFF.
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The ABS-ECU outputs the buzzer-sounding signal at the malfunction of the Hydraulic Brake Booster (HBB). (Also the ABS-ECU turns on the
brake warning light at the same time.)
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The buzzer will sound under the following cases:
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When the pump motor is locked
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When the pump motor is energized abnormally for long period.
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When the accumulator pressure is abnormally low.
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When the pressure switch circuit (for pump motor control) is open, and the pressure switch circuit (for low-pressure warning) is open or short.
TECHNICAL DESCRIPTION (COMMENT)
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The open circuit of the buzzer power supply circuit and the buzzer drive circuit of ABS-ECU, malfunction of the buzzer and the failure of buzzer
drive transistor in the ABS-ECU could be the cause of trouble.
TROUBLESHOOTING HINTS (The most likely causes for this condition:)
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Damaged wiring harness or connector
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Malfunction of the buzzer
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Malfunction of the ABS-ECU
DIAGNOSIS
Required Special Tool:
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MB991223: Harness Set
STEP 1. Check the buzzer circuit at ABS-ECU connector E-106.
1. Disconnect the ABS-ECU connector E-106 and measure at the harness side.
2. Turn the ignition switch to "ON" position.
3. Measure the voltage between terminal 44 and ground.
Q: Does the buzzer sound during the measurement?
YES: Replace the ABS-ECU and then go to Step 8.
NO: Go to Step 2.
STEP 2. Check the buzzer.
1. Remove the buzzer.
2. Connect the battery to the buzzer as shown on the illustration.
Q: Does the buzzer sound?
