Diagnosis System

1. The seat belt control ECU uses CAN and ISO 15765-4 communication protocol. The terminal arrangement of the DLC3 complies with SAE J1962 and matches the ISO 15765-4 format.
   Fig 1: Identifying DLC3 Connector Terminal

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
   SYMBOLS (TERMINALS NO.) CONDITION DESCRIPTION
   
   

   Symbols (Terminals 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	10 to 14 V
   CANH (6) - CANL	HIGH - level CAN bus line	Engine switch off	54 to 67 Ω
   CANH (6) - Battery positive	IGH - level CAN bus line	Engine switch off	1 MΩ or higher
   CANH (6) - CG (4)	HIGH - level CAN bus line	Engine switch off	3 MΩ or higher
   CANL (14) - Battery positive	LOW - level CAN bus line	Engine switch off	1 MΩ or higher
   CANL (14) - CG (4)	LOW - level CAN bus line	Engine switch off	3 MΩ or higher

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

HINT:

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

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

1. If the pre-collision safety system is not functioning properly, the driver is warned through the combination meter's master warning indicator and multi-information display warning message.
   Fig 2: Identifying Master And PCS Warning Indicator

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
2. Initial check.
   1. The initial check occurs when the engine switch is off for more than 2 seconds, and then the turned on (IG). The initial check consists of a pre-collision safety system diagnostic check with a duration of approximately 3 seconds.
   2. If a malfunction is detected during the initial check, the multi-information display will output "Check PCS" or "PCS DISABLED Now".
3. Constant check.
   1. The seat belt control ECU and cruise control ECU assembly (distance control ECU) constantly monitor the pre-collision safety system for malfunctions after the initial check (approximately 3 seconds after turning the engine switch on (IG).
   2. "Check PCS" or "PCS DISABLED Now" is displayed on the multi-information display in the combination meter assembly when the constant check detects malfunctions in the pre-collision safety system.
4. Review.
   MASTER WARNING INDICATOR CHART
   
   

   Master Warning Indicator	Warning	Message Detail	DTC	PCS Warning indicator
   ON	Check PCS	This message appears when the seat belt control ECU detects a system malfunction	x	ON
   Illuminate	PCS DISABLED Now	This message appears when the seat belt control ECU is in the fail-safe mode (see DTC CHECK / CLEAR  )	-	Blinking