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 it detects a malfunction in the ECU itself or in its circuits.

To check the 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 auxiliary battery voltage.

   Standard Voltage

   11 to 14 V

   If the voltage is below 11 V, recharge the auxiliary battery before proceeding to the next step.

2. Check the DLC3. Refer to GENERAL INFORMATION .

1. If the skid control ECU detects a malfunction, the ABS warning, brake warning / red (malfunction), brake warning / yellow (minor malfunction) and slip indicator lights will come on in order to warn the driver.
   Fig 1: Identifying ABS Warning Lights

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
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, brake warning / yellow (minor malfunction) 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 DLC3 and observing the blinking pattern of the ABS warning, brake warning / yellow (minor malfunction) and slip indicator lights, or by connecting the Techstream. TEST MODE PROCEDURE .

1. Release the parking brake.
   NOTE:

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

   HINT: 

   When the parking brake is applied or the brake fluid level is low, the brake warning light / red (malfunction) comes on.

2. When the power switch is turned on (IG), check that the VSC OFF indicator light comes on for approximately 3 seconds, and ABS warning, brake warning / red (malfunction), brake warning / yellow (minor malfunction) and slip indicator lights remain on until the power switch is turned on (READY).
   Fig 2: Identifying ABS Warning, Brake Warning & VSC OFF Indicator Lights

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

   HINT: 

   • If the warning light and indicator light check result is not normal, proceed to troubleshooting for the ABS warning, brake warning / red (malfunction), brake warning / yellow (minor malfunction), 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 come on)	Refer to ABS Warning Light does not Come ON
   Brake warning light / red (malfunction) circuit (Remains on)	Refer to Brake Warning Light Remains ON
   Brake warning light / red (malfunction) circuit (Does not come on)	Refer to Brake Warning Light does not Come ON
   Brake warning light / yellow (minor malfunction) circuit (Remains on)	Refer to Brake Control Warning Light Remains ON
   Brake warning light / yellow (minor malfunction) circuit (Does not come on)	Refer to Brake Control Warning 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