Diagnosis System

1. Check the DLC3. Refer to GENERAL INFORMATION .

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 the environment in which the problem occurred in the customer's vehicle should be simulated. No matter how experienced or skilled a technician may be, if he/she proceeds to troubleshooting without confirming the problem symptoms, he/she 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 a malfunction seems to occur as a result of vibration.
   Fig 1: Symptom Simulation Vibration Method

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

   HINT: 

   Perform this simulation method only during the primary check period of approximately 6 seconds after the ignition switch is turned to ON.

   1. PARTS OR SENSORS

      Apply slight vibration with a finger to the part or sensor suspected to be the cause of the problem, and check whether the malfunction occurs.

      NOTE:

      Applying strong vibration to relays may open the relays.

   2. CONNECTORS

      Slightly shake the connector vertically and horizontally.

   3. WIRE HARNESS

      Slightly shake the wire harness vertically and horizontally.

      HINT: 

      The connector joint and fulcrum of the vibration are the major areas that should be checked thoroughly.

1. Initial check
   1. Turn the ignition switch to ON.
   2. The passenger airbag ON/OFF indicator ("ON" and "OFF") comes on for approximately 4 seconds, then goes off for approximately 2 seconds.
   3. Approximately 6 seconds after the ignition switch is turned to ON, the passenger airbag ON/OFF indicator will indicate ON or OFF depending on the conditions listed below.

      Front Passenger Seat Condition	Passenger Airbag ON/OFF Indicator		SRS Warning Light
      	ON indicator	OFF indicator
      Vacant	OFF	OFF	OFF
      Adult is seated.	ON	OFF	OFF
      Child is seated.	OFF	ON	OFF
      Child restraint system is set.	OFF	ON	OFF
      Front passenger occupant classification failure	OFF	ON	ON

      HINT: 

      • The passenger airbag ON/OFF indicator is based on the timing chart below in order to check the indicator light circuit.
      • When the occupant classification system has trouble, both the SRS warning light and the passenger airbag ON/OFF indicator ("OFF") come on. In this case, check the DTCs in the airbag system first.
      Fig 2: Passenger Airbag ON/OFF Indicator Timing Chart

      Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

1. Turn the ignition switch to ON.
   Fig 3: Identifying Passenger Airbag ON/OFF Indicator

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
2. Check that the passenger airbag ON/OFF indicator ("ON" and "OFF") comes on for approximately 4 seconds, then goes off for approximately 2 seconds.

   HINT: 

   Refer to the table in the previous step regarding the passenger airbag ON/OFF indicator when the ignition switch is turned to ON and approximately 6 seconds pass.