Diagnosis System

When troubleshooting a vehicle with the diagnosis system, the only difference from the usual troubleshooting procedure is connecting the Techstream to the vehicle and reading various data output from the vehicle's skid control ECU.

The skid control ECU records DTCs when the computer detects a malfunction in the ECU itself or in its circuits. To check for DTCs, connect the Techstream to the DLC3 on the vehicle. The Techstream enables you to clear the DTCs, activate the various actuators, and check the Freeze Frame Data and Data List.

1. Check 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.
   Fig 1: Identifying DLC3 Connector Terminals

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

   The ECU uses ISO 15765-4 for communication. The terminal arrangement of the DLC3 complies with SAE J1962 and matches the ISO 15765-4 format.

   If the result is not as specified, the DLC3 may have a malfunction. Repair or replace the harness and connector.

   Verify the conditions listed in the table below.

   Terminal No. (Symbol)	Terminal Description	Condition	Specified Condition
   7 (SIL) - 5 (SG)	Bus "+" line	During transmission	Pulse generation
   4 (CG) - Body ground	Chassis ground	Always	Below 1 Ω
   5 (SG) - Body ground	Signal ground	Always	Below 1 Ω
   16 (BAT) - Body ground	Battery positive	Always	11 to 14 V
   6 (CANH) - 14 (CANL)	CAN bus line	*Ignition switch off	54 to 69 Ω
   6 (CANH) - 4 (CG)	HIGH-level CAN bus line	*Ignition switch off	200 Ω or higher
   14 (CANL) - 4 (CG)	LOW-level CAN bus line	*Ignition switch off	200 Ω or higher
   6 (CANH) - 16 (BAT)	HIGH-level CAN bus line	*Ignition switch off	6 kΩ or higher
   14 (CANL) - 16 (BAT)	LOW-level CAN bus line	*Ignition switch off	6 kΩ or higher

   NOTE:

   *: Before measuring the resistance, leave the vehicle as is for at least 1 minute and do not operate the ignition switch, any other switches or the doors.

   HINT: 

   Connect the Techstream to the DLC3, turn the ignition switch on (IG) and attempt to use the Techstream. If the display indicates that a communication error has occurred, there is a problem either with the vehicle or with the Techstream.

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

1. If the skid control ECU detects a malfunction, the ABS warning, BRAKE warning and SLIP indicator lights will come on in order to warn the driver.
2. The DTCs are simultaneously stored in the memory. The DTCs can be read by connecting SST between terminals TC and CG of the DLC3 and observing the blinking pattern of the ABS warning and SLIP indicator lights, or by connecting the Techstream. Refer to DTC CHECK / CLEAR .
3. This system has a Test Mode (signal check) function.

   The DTCs can be read by connecting SST between terminals TS and CG of the ABS warning and SLIP indicator lights, or by connecting the Techstream. Refer to TEST MODE PROCEDURE .

1. Release the parking brake.
   NOTE:

   When releasing parking brake, move the shift lever to P for safety.

   HINT: 

   When 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 on (IG), check that the ABS warning, BRAKE warning, TRAC OFF indicator, VSC OFF indicator and SLIP indicator lights come on for approximately 3 seconds.

   HINT: 

   • If the warning light and indicator light initial check result is not normal, proceed to LIGHTING SYSTEM troubleshooting for the ABS warning, BRAKE warning, TRAC OFF indicator, VSC OFF indicator and SLIP indicator light circuits.
   • If the indicator remains on or does not come on, proceed to troubleshooting for the light circuits listed below.

   Trouble Area	See procedure
   ABS warning light circuit (Remains on)	Refer to ABS Warning Light Remains ON
   ABS warning light circuit (Does not comes on)	Refer to ABS Warning Light does not Come ON
   BRAKE warning light (Remains on)	Refer to Brake Warning Light Remains ON
   BRAKE warning light (Does not come on)	Refer to Brake Warning Light does not Come ON
   TRAC OFF indicator light circuit (Remains on)	Refer to TRAC OFF Indicator Light Remains ON
   TRAC OFF indicator light circuit (Does not come on)	Refer to TRAC OFF Indicator Light does not Come ON
   VSC OFF indicator light circuit (Remains on)	Refer to VSC OFF Indicator Light Remains ON
   VSC OFF indicator light circuit (Does not come on)	Refer to VSC OFF Indicator Light does not Come ON
   SLIP indicator light circuit (Remains on)	Refer to Slip Indicator Light Remains ON
   SLIP indicator light circuit (Does not come on)	Refer to Slip Indicator Light does not Come ON