ABS does not Operate

DESCRIPTION

When the electronically controlled brake system is operating, as the input piston and output piston are not directly connected, the kickback of the brake pedal is minimal during ABS operation and the driver may not notice that ABS operated.

CAUTION / NOTICE / HINT

Note

After replacing the skid control ECU (brake booster with master cylinder assembly), perform linear solenoid valve offset learning, ABS holding solenoid valve learning, yaw rate and acceleration sensor zero point calibration and system information memorization after performing "Reset Memory".

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PROCEDURE

BRAKE PROBLEM CHECK

Check if the slip indicator light was illuminated or blinking when ABS did not operate.

Tech Tips

When the VSC system is normal and ABS is operating, the slip indicator light blinks.
When the VSC system is malfunctioning, the slip indicator light illuminates.

Result

Result	Proceed to
The slip indicator light was blinking.	A
The slip indicator light was illuminated.	B

A

END

B

CHECK DTC AND FREEZE FRAME DATA

Using the GTS, check DTCs and Freeze Frame Data.

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Chassis > ABS/VSC/TRC > Trouble Codes

Result

Result	Proceed to
DTCs are not output.	A
DTCs are output.	B

B

REPAIR CIRCUITS INDICATED BY OUTPUT DTCS Click here

A

PERFORM OPERATION CHECK DRIVING

Check that ABS operates using a drum tester or equivalent.

CAUTION:

When using a drum tester, enter Inspection Mode or VSC off mode and perform inspection with the TRC and VSC systems disabled to prevent the vehicle from moving suddenly due to TRC or VSC operation.

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OK
ABS operates.

Result

Proceed to
OK
NG

OK

END

NG

REPLACE BRAKE BOOSTER WITH MASTER CYLINDER ASSEMBLY for LHD: Click here
REPLACE BRAKE BOOSTER WITH MASTER CYLINDER ASSEMBLY for RHD: Click here

ELECTRONICALLY CONTROLLED BRAKE SYSTEM ABS does not Operate