Airbag System Diagnosis System

Check the DLC3 (COROLLA_ZRE142 RM000000UZ20CBX.html).

VIBRATION METHOD: When a malfunction seems to occur as a result of vibration.

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.
   

   NOTICE:

   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.

Primary check

1. Turn the ignition switch off. Wait for at least 2 seconds, then turn the ignition switch to ON. The SRS warning light comes on for approximately 6 seconds and the diagnosis of the airbag system (including the seat belt pretensioners) is performed.
   

   HINT:

   If malfunctions are detected during the primary check, the SRS warning light remains on even after the primary check period of approximately 6 seconds.

Constant check

1. After the primary check, the airbag sensor assembly constantly monitors the airbag system for malfunctions.
   

   HINT:

   If malfunctions are detected during the constant check, the airbag sensor assembly functions as follows:

   1. The SRS warning light comes on.
      
   2. The SRS warning light goes off, and then comes on. This indicates a source voltage drop. The SRS warning light goes off 10 seconds after the source voltage returns to normal.
      

Review

1. When the airbag system is normal:
   The SRS warning light comes on only during the primary check period of approximately 6 seconds after the ignition switch is turned to ON.
   

2. When the airbag system is malfunctioning:
   

   1. The SRS warning light remains on even after the primary check period.
      
   2. The SRS warning light goes off after the primary check, but comes on again during the constant check.
      
   3. The SRS warning light does not come on when turning the ignition switch from off to ON.
      

   HINT:

   The airbag sensor assembly keeps the SRS warning light on if airbags have been deployed.

Turn the ignition switch to ON, and check that the SRS warning light comes on for approximately 6 seconds (primary check).

Check that the SRS warning light goes off approximately 6 seconds after the ignition switch is turned to ON (constant check).

HINT:

When any of the following symptoms occur, refer to Problem Symptoms Table (COROLLA_ZRE142 RM000000XFA0A5X.html).

1. The SRS warning light comes on occasionally after the primary check period.
   
2. The SRS warning light comes on, but a DTC is not output.
   
3. The ignition switch is turned from off to ON, but the SRS warning light does not come on.
   

Initial check

1. Turn the ignition switch to ON.
   

2. The passenger airbag ON/OFF indicator 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 be ON/OFF depending on the conditions listed below.
   
   

   Indicator Operation

   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 installed	OFF	ON	OFF
   Front passenger occupant classification failure	OFF	ON	ON

   HINT:

   1. The passenger airbag ON/OFF indicator is based on the timing chart below in order to check the indicator light circuit.
      
   2. When the occupant classification system is malfunctioning, 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. Then troubleshoot the occupant classification system if DTC B1650/32 is detected, and troubleshoot the passenger airbag ON/OFF indicator if DTC B1660/43 is detected.
      
   
   
   
   

Turn the ignition switch to ON.

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 indicator operation table in the preceding step regarding the passenger airbag ON/OFF indicator when the ignition switch is turned to ON and approximately 6 seconds have elapsed.

FUNCTION OF ACTIVATION PREVENTION MECHANISM

1. An activation prevention mechanism is built into the connector (on the center airbag sensor assembly side) of the airbag system squib circuit to prevent accidental airbag activation.
   

2. This mechanism closes the circuit when the connector is disconnected by bringing the short spring into contact with the terminals and insulating the circuit from external power sources to prevent accidental airbag activation.
   

RELEASING OF ACTIVATION PREVENTION MECHANISM

1. To release the activation prevention mechanism, insert a piece of paper with the same thickness as the male terminal (approximately 0.5 mm (0.0197 in.)) between the terminals and the short spring to break the connection.
   





2. Refer to the following illustrations concerning connectors utilizing the activation prevention mechanism and its release method.
   

   CAUTION:

   Never release the activation prevention mechanism on the squib connector even when performing an inspection with the squib disconnected.

   NOTICE:

   1. Do not release the activation prevention mechanism unless specifically instructed to by the troubleshooting procedure.
      
   2. To prevent the terminal and the short spring from being damaged, always use a piece of paper with the same thickness as the male terminal.