Diagnosis System

1. Inspect the battery voltage.

   Standard voltage: 

   11 to 14 V 

   If the voltage is below 11 V, recharge the battery before proceeding.

2. Check the DLC3.

   The skid control ECU uses CAN and the ISO 9141-2 for communication protocol. The terminal arrangement of the DLC3 complies with SAE J1962 and matches the ISO 9141-2 format. Verify the conditions listed in the table below.

   Fig 1: Identifying DLC3 Connector Terminal

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
   CONNECTOR TERMINAL VOLTAGE SPECIFICATION TABLE
   
   

   Symbols (Terminal No.)	Terminal Description	Condition	Specified Condition
   SIL (7) - SG (5)	Bus "+" line	During transmission	Pulse generation
   CG (4) - Body ground	Chassis ground	Always	Below 1 Ω
   SG (5) - Body ground	Signal ground	Always	Below 1 Ω
   BAT (16) - Body ground	Battery positive	Always	11 to 14 V
   CANH (6) - CANL (14)	HIGH-level CAN bus line	Ignition switch off	54 to 67 Ω
   CANH (6) - BAT (16)	HIGH-level CAN bus line	Ignition switch off	6 kΩ or higher
   CANH (6) - CG (4)	HIGH-level CAN bus line	Ignition switch off	200 Ω or higher
   CANL (14) - BAT (16)	LOW-level CAN bus line	Ignition switch off	6 kΩ or higher
   CANL (14) - CG (4)	LOW-level CAN bus line	Ignition switch off	200 Ω or higher

   HINT:

   If the display shows a communication error message when the cable of the intelligent tester is connected to the DLC3, the ignition switch is turned to the ON position and the intelligent tester is operated, there is a problem on either the vehicle side or the tester side.

   • If communication is normal when the tester is connected to another vehicle, inspect the DLC3 on the original vehicle.
   • If communication is still not possible when the tester is connected to another vehicle, the problem is probably in the tester itself. Consult the Service Department listed in the tester's operator's manual.

1. If the skid control ECU detects a malfunction, the ABS, VSC, BRAKE warning lights and SLIP indicator light will come on, in order to warn the driver.
   Fig 2: Identifying ABS, BRAKE, VSC Warning Lights & SLIP Indicator Light

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

   The table below indicates which lights will come on when there is a malfunction in a particular function.

   TROUBLESHOOTING TABLE
   
   

   Item/Trouble Area	ABS	EBD	BA	TRAC	VSC
   ABS Warning Light	◦	◦	◦	-	-
   BRAKE Warning Light	-	◦	-	-	-
   VSC Warning Light	◦	◦	◦	◦	◦
   SLIP Indicator Light	◦	◦	◦	◦	◦
   ◦: Light ON
   -: Light OFF

   • DTCs are simultaneously stored in the memory. The DTCs can be read by connecting the SST between terminals TC and CG of the DLC3 and observing the blinking pattern of the ABS warning light by connecting the intelligent tester (See DTC CHECK/CLEAR  ).
   • This system has a signal check function (TEST MODE).

     The DTC can be read by connecting the intelligent tester and observing the blinking pattern of the ABS warning light.

1. Release the parking brake.
   NOTE: Before releasing the parking brake, move the shift lever to the P position for safety.

   HINT:

   When the parking brake is applied or the level of the brake fluid is low, the BRAKE warning light comes on.

2. When the ignition switch is turned to the ON position, check that the ABS, VSC, and BRAKE warning lights and SLIP indicator light come on for approximately 3 seconds.

   HINT:

   If the ECU stores any DTCs, the ABS, BRAKE, and VSC warning lights and SLIP indicator light come on.

   Fig 3: Identifying ABS, BRAKE, VSC Warning Lights & SLIP Indicator Light

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

   If the indicator remains on or does not come on, proceed to troubleshooting for the light circuits listed below.

   TROUBLESHOOTING TABLE
   
   

   Trouble Area
   ABS WARNING LIGHT REMAINS ON
   ABS WARNING LIGHT DOES NOT COME ON
   BRAKE WARNING LIGHT REMAINS ON
   BRAKE WARNING LIGHT DOES NOT COME ON
   VSC WARNING LIGHT REMAINS ON
   VSC WARNING LIGHT DOES NOT COME ON
   SLIP INDICATOR LIGHT REMAINS ON
   SLIP INDICATOR LIGHT DOES NOT COME ON

HINT:

The most difficult case in troubleshooting is when no symptoms occur. In such cases, a thorough customer problem analysis must be carried out. Then the same or similar conditions and environment in which the problem occurred in the customer's vehicle should be reproduced. No matter how experienced or skilled a technician may be, if he proceeds to troubleshoot without confirming the problem symptoms, he will likely overlook something important and make a wrong guess at some points in the repair operation. This leads to a standstill in troubleshooting.

1. Vibration method: When vibration seems to be the major cause.

   HINT:

   Perform the simulation method only during the primary check period (for approximately 6 seconds after the ignition switch is turned to the ON position).

   1. Slightly vibrate the part of the sensor considered to be the problem cause with your fingers and check whether the malfunction occurs.
   2. Slightly shake the connector vertically and horizontally.

      HINT:

      Shaking the relays too strongly may result in open relays.

   3. Slightly shake the wire harness vertically and horizontally. The connector joint and fulcrum of the vibration are the major areas to be checked thoroughly.
      Fig 4: Symptom Simulation Vibration Method

      Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002