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 computer itself or in its circuits.

To check the DTCs, connect the Techstream to the DLC3 on the vehicle. The Techstream enables you to erase 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 to the next step.

2. Check the DLC3 (See HOW TO TROUBLESHOOT ECU CONTROLLED SYSTEMS ).

1. If the skid control ECU detects a malfunction, the ABS warning and brake warning will blink in order to warn the driver.

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

   Fig 1: Identifying ABS Warning Light And Brake Warning Light

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
   DIAGNOSTIC PROCEDURE CHART
   
   

   Item / Trouble Area	ABS	EBD
   ABS warning light	◦	◦
   Brake warning light	-	◦
   ◦: Light ON -: Light OFF

   • The 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, or by connecting a Techstream.
   • This system has a Test Mode (signal check) function (See TEST MODE PROCEDURE  ).

1. Release the parking brake.
   NOTE: When releasing the parking brake, move the shift lever to the P position for safety (for automatic transaxle model) or set chocks to hold the vehicle for safety (for manual transaxle model).

   HINT:

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

   Fig 2: Identifying ABS Warning Light And Brake Warning Light

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
2. When the ignition switch is turned to ON, check that the ABS warning and brake warning light come on for approximately 3 seconds.

   HINT:

   If the warning light and indicator light check result is not normal, proceed to troubleshooting for the ABS warning and brake warning light circuits.

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

   DIAGNOSTIC PROCEDURE CHART
   
   

   Trouble Area	See procedure
   ABS warning light circuit (Remains on)	ABS WARNING LIGHT REMAINS ON
   ABS warning light circuit (Does not come on)	ABS WARNING LIGHT DOES NOT COME ON
   Brake warning light circuit (Remains on)	BRAKE WARNING LIGHT REMAINS ON
   Brake warning light circuit (Does not come on)	BRAKE WARNING LIGHT DOES NOT COME ON