PRECAUTION

id040300804100

With ABS (ABS/TCS)

1. The ABS warning light, BRAKE system warning light, TCS OFF light and/or TCS OFF 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)	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 for more than 60 s.	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 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 (ABS/TCS) HU/CM ignition terminal Z 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.

^*1 :

In cases where the light may illuminate, only when ABS (ABS/TCS) HU/CM detects that a rear wheel`s speed sensor is malfunctioning.

^*2 :

If battery voltage drops below 9 V while vehicle speed is greater than 6 km/h {3.7mph} , ABS (ABS/TCS) HU/CM records DTC B1318.


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 and TCS control
The following lights illuminate: • TCS OFF light	When the engine coolant temperature is below 0°C {32°F}.(^*1)	When engine is started and engine coolant temperature rises above 0°C {32°F}.)	ABS: Cuts control. EBD: Cuts control. TCS: 1. If TCS is operating, cuts control after gradually released TCS control value. 2. If TCS is not operating, cuts control.
All the following lights flash: • ABS warning light • BRAKE system warning light • TCS OFF light	When confirming DTC, PID/DATA and ACTIVE COMMAND MODES item using NGS tester.	When ABS ON-BOARD DIAGNOSTIC SYSTEM is released.	ABS: Cuts control. EBD: Cuts control. TCS: Cuts control.
The following light illuminates: • TCS OFF light	For 1 second after starting the engine.	More than 1 second after starting the engine.	ABS: Cuts control. EBD: Cuts control TCS: Cuts control.
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, TCS control.

^*1 :

DTC U2021 for past malfunction is not recorded in the ABS/TCS HU/CM. DTC U2021 for present malfunction displayed, but goes out when engine coolant temperature rises above 0°C {32°F}.

2. Precautions during servicing of ABS

The ABS (ABS/TCS) 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 (ABS/TCS) hydraulic unit and control module (ABS (ABS/TCS) 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 (ABS/TCS) HU/CM. This function can find malfunctions that do not occur during periodic inspections. Connect the WDS or equivalent to the DLC-2.The stored malfunction will be displayed in the order of occurrence. To find out the causes of ABS (ABS/TCS) 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 (ABS/TCS) 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 (ABS/TCS) HU/CM memory. Also, if the ABS (ABS/TCS) 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 (ABS/TCS) 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 rear wheel malformations.

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

• To protect the ABS (ABS/TCS) HU/CM, make sure the ignition is off before connecting or disconnecting the ABS (ABS/TCS) 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 (ABS/TCS) component or the conventional brake system.

• The ABS (ABS/TCS) 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).

With DSC

1. The ABS warning light and/or BRAKE system warning light and/or DSC indicator light and/or DSC OFF 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, TCS and DSC control
• ABS warning light • BRAKE system warning light • DSC indicator light • DSC OFF light	Under any of the following conditions: • When the front wheels are jacked up, struck, or placed on a chassis roller, and only the front wheel ABS wheel speed sensors are spun for more than 60 s.	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: Cuts control. • TCS: Cuts control. • DSC: Cuts control.
	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.)
	Battery voltage at DSC HU/CM ignition terminal drops below about 9.5 V.	Battery voltage rises above about 9.5 V.	ABS: Operates control. EBD: Operates control. TCS: Operates control. DSC: Operates control.
• Brake system warning light • DSC indicator light • DSC OFF light	Brake fluid amount is low.	Brake fluid level lower than recommended amount.	ABS: Operates control. EBD: Operates control. TCS: Cuts control. DSC: Cuts control.

2. Precautions during servicing of DSC The DSC is composed of electrical and mechanical parts. It is necessary to categorize malfunctions as being either electrical or hydraulic when performing troubleshooting.

(1) Malfunction in electrical system

• The control module has an on-board diagnostic function. With this function, the ABS warning light and/or BRAKE system warning light and/or DSC indicator light and/or DSC OFF light will come on when there is a problem in the electrical system.

Also, past and present malfunctions are recorded in the control module. This function can find malfunction that do not occur during periodic inspections. Connect the WDS or equivalent to the DLC-2. The stored malfunctions will be displayed in the order of occurrence. To fine out the causes of DSC 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 control module usually operates normally. Be careful when searching for the cause of malfunction.

• After repair, it is necessary to clear the DTC from the control module memory.

Also, if the DSC 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 control module, 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 the ABS warning light goes off, and then clear the DTC.

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

Caution

• In DSC vehicles, when any DSC HU/CM, steering angle sensor, combined sensor are replaced. Perform the sensor standard point installation of each sensor.

• To protect the control module, make sure the ignition is off before connecting or disconnecting the control module 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 a DSC component or the conventional brake system.

• The hydraulic unit contains delicate mechanical parts. If foreign materials get into the component, the DSC 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 DSC does not. Make sure foreign materials do not get inside when servicing the DSC (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 WDS or equivalent to DLC.

2. Turn ignition switch 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.

• If PID value is unstable, check for poor connection.

Inspection method for sensor connectors or wires

1. Connect WDS or equivalent to DLC.

2. Turn ignition switch 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.

• If PID value is unstable, check for poor connection.

Inspection method for sensors

1. Connect WDS or equivalent to DLC.

2. Turn ignition switch 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.