PRECAUTION [ABS]

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1.  The ABS warning light, brake system warning light illuminate 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)	Only the front wheels rotate under the following condition while jacked up, stuck, or on the chassis dynamometer: •  Detected 8 times for a continuous 20 s while at a vehicle speed of 20 km/h {12 mph} or more (One detection period is when ignition is switched from ON to off).	After turning off the ignition once and then restarting the engine, vehicle is driven at 10 km/h {6.2 mph} or more ,and then normal operation is verified.	•  ABS: Cuts control. •  EBD: 1.  Cuts control, in cases where the light may illuminate, only when ABS HU/CM detects that a wheel speed sensor determines that more than the two rear 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.
	Sudden acceleration/deceleration.
	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 AF drops below about 9 to 10 V.(*2)	Battery voltage rises above about 10 V. (Only brake system warning light goes out.)	•  ABS: Operates control. •  EBD: Operates control.
•  Brake system warning light	Brake fluid amount is low.	Brake fluid level within the specification.	•  ABS: Operates control •  EBD: Operates control
	Vehicles without malfunction warning light(*3) Improper brake switch input to PCM. (Stuck ON or OFF)*4	Correct brake signal input to PCM.

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 malfunction will be displayed in the order of occurrence. To find out the causes of ABS malfunction, 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 HU/CM (ABS motor or ABS motor relay or solenoid valve), the ABS warning light may not go off (^*) even when the ignition is switched to 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 rear wheel malformations.

•  When repairing, if the ABS related connectors are disconnected and the ignition is switched to ON, the ABS HU/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 HU/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 check 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 checked.

Inspection method for switch connectors or wires

1.  Connect the M-MDS to the DLC-2.

2.  Switch the ignition 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, check for poor connection.

Inspection method for sensor connectors or wires

1.  Connect the M-MDS to the DLC-2.

2.  Switch the ignition 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, check for poor connection.

Inspection method for sensors

1.  Connect the M-MDS to the DLC-2.

2.  Switch the ignition 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, check 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 check method

1.  Check the connection condition of each female terminal.

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

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