PRECAUTION [ABS]

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1.  The ABS warning light, BRAKE system warning light even when the system is normal.

Warning lights that may illuminate and/or flash	Cases in which the light may illuminate	Conditions in which the light will go out	ABS, EBD, control
Any or all the following light(s) illuminate: •  ABS warning light •  BRAKE system warning light(*1)	Under any of the following conditions: •  When the front wheels are jacked up, stuck, or placed on a chassis roller, and only the front wheel ABS wheel speed sensors are spun.	After turning ignition switch OFF, vehicle is driven at speed greater than 10 km/h {6.2 mph} and normal operation is confirmed.	•  ABS: Cuts control. •  EBD: 1.  Cuts control, in cases where the light may illuminate, only when ABS CM detects that a wheel speed sensor determines that more than the two wheels are malfunctioning. 2.  Operates control, if wheel speed sensor determines that more than 3 wheels are functioning correctly.
	Parking brake is not fully released while driving.
	Brake drag.
	Left/right or front/rear tires are different. (Size, radius, tire pressure, or wear is other than that listed on tire label.)
All the following lights illuminate: •  ABS warning light •  BRAKE system warning light	Battery voltage at ABS HU/CM ignition terminal N drops below approx. 8 V.(*2)	Battery voltage rises above approx. 8 V.	ABS: Cuts control. EBD: Cuts control.

2.  Precautions during servicing of ABS

The ABS is composed of electrical and mechanical parts.It is necessary to categorize malfunctions as being either electrical or hydraulic when performing troubleshooting.

(1)  Malfunctions in electrical system

•  The ABS hydraulic unit and control module (ABS HU/CM) has an on-board diagnostic function. With this function, the ABS warning light and/or BRAKE system warning light will come on when there is a problem in the electrical system. Also, past and present malfunctions are recorded in the ABS HU/CM. This function can find malfunctions that do not occur during periodic inspections. Connect the M-MDS to the DLC-2.The stored malfunctions will be displayed in the order of occurrence.To find out the causes of ABS malfunctions, use these on-board diagnostic results.

•  If a malfunction occurred in the past but is now normal, the cause is likely a temporary poor connection of the harness. The ABS HU/CM usually operates normally. Be careful when searching for the cause of malfunction.

•  After repair, it is necessary to clear the

DTC from the ABS HU/CM memory. Also, if the ABS related parts have been replaced, verify that the no DTC has been displayed after repairs.

•  After repairing the ABS wheel-speed sensor or ABS sensor rotor, or after replacing the ABS CM (ABS motor or ABS motor relay or solenoid valve), the ABS warning light may not go off (^*) even when the ignition switch is turned on. In this case, drive the vehicle at a speed of more than 10 km/h {6.2 mph}, make sure that ABS warning light goes off, and then clear the DTC.

* The BRAKE system warning light also illuminates when any two wheels malformations, or battery voltage drops below 8 V.

•  When repairing, if the ABS related connectors are disconnected and the ignition switch is turned on, the ABS CM will mistakenly detect a fault and record it as a malfunction.

•  To protect the ABS HU/CM, make sure the ignition is off before connecting or disconnecting the ABS CM connector.

(2)  Malfunctions in hydraulic system

•  Symptoms in a hydraulic system malfunction are similar to those in a conventional brake malfunction. However, it is necessary to determine if the malfunction is in an ABS component or the conventional brake system.

•  The ABS hydraulic unit contains delicate mechanical parts. If foreign materials get into the component, the ABS may fail to operate. Also, it will likely become extremely difficult to find the location of the malfunction in the event that the brakes operate but the ABS does not. Make sure foreign materials do not get inside when servicing the ABS (e.g. brake fluid replacement, pipe removal).

Intermittent Concern Troubleshooting

Vibration method

•  If malfunction occurs or becomes worse while driving on a rough road or when engine is vibrating, perform the steps below.

Note

•  There are several reasons why vehicle or engine vibration could cause an electrical malfunction. Some of the things to inspect for are:

―  Connectors not fully seated.

―  Wire harnesses not having full play.

―  Wires laying across brackets or moving parts.

―  Wires routed too close to hot parts.

•  An improperly routed, improperly clamped, or loose harness can cause wiring to become pinched between parts.

•  The connector joints, points of vibration, and places where wire harnesses pass through the firewall, body panels, etc. are the major areas to be inspected.

Inspection method for switch connectors or wires

1.  Connect M-MDS to DLC-2.

2.  Turn ignition key to ON (Engine OFF).

Note

•  If engine starts and runs, perform the following steps at idle.

3.  Access PIDs for the switch you are inspecting.

4.  Turn switch on manually.

5.  Shake each connector or wire harness a bit vertically and horizontally while monitoring the PID.

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•  If PID value is unstable, inspect poor connection.

Inspection method for sensor connectors or wires

1.  Connect M-MDS to DLC-2.

2.  Turn ignition key to ON (Engine OFF).

Note

•  If engine starts and runs, perform the following steps at idle.

3.  Access PIDs for the switch you are inspecting.

4.  Shake each connector or wire harness a bit vertically and horizontally while monitoring the PID.

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•  If PID value is unstable, inspect poor connection.

Inspection method for sensors

1.  Connect M-MDS to DLC-2.

2.  Turn ignition key to ON (Engine OFF).

Note

•  If engine starts and runs, perform the following steps at idle.

3.  Access PIDs for the switch you are inspecting.

4.  Vibrate the sensor slightly with your finger.

•  If PID value is unstable or malfunction occurs, inspect sensor for poor connection and/or poorly mounted sensor.

Malfunction data monitor method

1.  Perform malfunction reappearance test according to malfunction reappearance mode and malfunction data monitor. The malfunction cause is found in the malfunction data.

Connector terminal inspection method

1.  Inspect the connection condition of each female terminal.

2.  Insert male terminal; fit female terminal size to female terminal and inspect to see whether malfunction is in female terminal or not.

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