Dtc B1774 Pressure Sensor Circuit Malfunction

Vehicle Interior. Corolla. Zre142 Aze141
Supplemental Restraint Systems. Corolla. Zre142 Aze141

DESCRIPTION

WIRING DIAGRAM

INSPECTION PROCEDURE

CHECK CONNECTORS

CHECK FRONT SEAT WIRE RH (SHORT TO B+)

CHECK FRONT SEAT WIRE RH (OPEN)

CHECK FRONT SEAT WIRE RH (SHORT TO GROUND)

CHECK FRONT SEAT WIRE RH (SHORT)

CHECK FOR DTC

REPLACE OCCUPANT CLASSIFICATION SENSOR (FRONT SEAT CUSHION ASSEMBLY)

PERFORM ZERO POINT CALIBRATION

CHECK FOR DTC

PERFORM SENSITIVITY CHECK

DTC B1774 Pressure Sensor Circuit Malfunction

DTC B1775 Pressure Sensor Power Source Circuit Malfunction


DESCRIPTION

The pressure sensor circuit consists of the occupant classification ECU and the occupant classification sensor.
The occupant classification sensor sends the pressure signal to the occupant classification ECU.
DTC B1774 and B1775 are recorded when a malfunction is detected in the pressure sensor circuit.

DTC No.
DTC Detecting Condition
Trouble Area
B1774
B1775
  1. The occupant classification ECU receives a short circuit signal, open circuit signal and short circuit to ground signal or a short circuit to B+ signal in the pressure sensor circuit for 2 seconds.
  2. Occupant classification sensor malfunction
  3. Occupant classification ECU malfunction
  1. Front seat wire RH
  2. Occupant classification sensor
  3. Occupant classification ECU
HINT:
When DTC B1650/32 is detected as a result of troubleshooting for the airbag system, check the DTCs stored in the occupant classification ECU. When DTC B1774 and B1775 are output, perform troubleshooting for those DTCs.

WIRING DIAGRAM


Corolla. Zre142 Aze141.Supplemental Restraint Systems.Airbag System. Dtc B1774 Pressure Sensor Circuit Malfunction


INSPECTION PROCEDURE

HINT:
  1. If troubleshooting (wire harness inspection) is difficult to perform, remove the passenger seat installation bolts to access the underside of the seat cushion.
  2. In the above case, hold the seat so that it does not fall down. Holding the seat for a long period of time may damage the seat and deform the seat rails. Hold the seat only as necessary.
  3. After performing the zero point calibration, check for DTCs to confirm that the calibration is completed normally. (If it fails, DTC B1797 will be output.)
1.CHECK CONNECTORS

  1. Turn the ignition switch off.

  1. Disconnect the cable from the negative (-) battery terminal.

  1. Check that the connectors are properly connected to the occupant classification ECU and the occupant classification sensor.

    OK:
    The connectors are properly connected.
    HINT:
    If the connectors are not connected securely, reconnect the connectors and proceed to the next inspection.

  1. Disconnect the connectors from the occupant classification ECU and the occupant classification sensor.

  1. Check that the terminals of the connectors are not damaged.

    OK:
    The terminals are not deformed or damaged.


NG
REPLACE FRONT SEAT WIRE RH
OK


2.CHECK FRONT SEAT WIRE RH (SHORT TO B+)


    Corolla. Zre142 Aze141.Supplemental Restraint Systems.Airbag System. Dtc B1774 Pressure Sensor Circuit Malfunction

  1. Connect the cable to the negative (-) battery terminal.

  1. Turn the ignition switch to ON.

  1. Measure the voltage according to the value(s) in the table below.

    Standard Voltage:
    Tester Connection
    		Switch Condition
    		Specified Condition
    R2-6 (PS) - Body ground
    		Ignition switch ON
    		Below 1 V
    R2-7 (VPS) - Body ground
    		Ignition switch ON
    		Below 1 V
    R2-15 (GPS) - Body ground
    		Ignition switch ON
    		Below 1 V


NG
REPLACE FRONT SEAT WIRE RH
OK


3.CHECK FRONT SEAT WIRE RH (OPEN)


  1. Turn the ignition switch off.


    Corolla. Zre142 Aze141.Supplemental Restraint Systems.Airbag System. Dtc B1774 Pressure Sensor Circuit Malfunction

  1. Disconnect the cable from the negative (-) battery terminal.

  1. Using SST, connect terminals 1 (GPS) and 3 (VPS), and connect terminals 2 (PS) and 3 (VPS) of connector C.

    NOTICE:
    Do not forcibly insert SST into the terminals of the connector when connecting the wire.
SST
09843-18040

  1. Measure the resistance according to the value(s) in the table below.

    Standard Resistance:
    Tester Connection
    		Condition
    		Specified Condition
    R2-6 (PS) - R2-7 (VPS)
    		Always
    		Below 1 Ω
    R2-7 (VPS) - R2-15 (GPS)
    		Always
    		Below 1 Ω


NG
REPLACE FRONT SEAT WIRE RH
OK


4.CHECK FRONT SEAT WIRE RH (SHORT TO GROUND)


    Corolla. Zre142 Aze141.Supplemental Restraint Systems.Airbag System. Dtc B1774 Pressure Sensor Circuit Malfunction

  1. Disconnect SST from connector C.

  1. Measure the resistance according to the value(s) in the table below.

    Standard Resistance:
    Tester Connection
    		Condition
    		Specified Condition
    R2-6 (PS) - Body ground
    		Always
    		1 MΩ or higher
    R2-7 (VPS) - Body ground
    		Always
    		1 MΩ or higher
    R2-15 (GPS) - Body ground
    		Always
    		1 MΩ or higher


NG
REPLACE FRONT SEAT WIRE RH
OK


5.CHECK FRONT SEAT WIRE RH (SHORT)


    Corolla. Zre142 Aze141.Supplemental Restraint Systems.Airbag System. Dtc B1774 Pressure Sensor Circuit Malfunction

  1. Measure the resistance according to the value(s) in the table below.

    Standard Resistance:
    Tester Connection
    		Condition
    		Specified Condition
    R2-6 (PS) - R2-15 (GPS)
    		Always
    		1 MΩ or higher
    R2-7 (VPS) - R2-15 (GPS)
    		Always
    		1 MΩ or higher


NG
REPLACE FRONT SEAT WIRE RH
OK


6.CHECK FOR DTC

  1. Connect the connectors to the occupant classification ECU and the occupant classification sensor.

  1. Connect the cable to the negative (-) battery terminal.

  1. Turn the ignition switch to ON.

  1. Clear the DTCs stored in the occupant classification ECU (COROLLA_ZRE142 RM0000010VK07TX.html).

  1. Clear the DTCs stored in the center airbag sensor assembly (COROLLA_ZRE142 RM000000XFE0H1X.html).

  1. Turn the ignition switch off.

  1. Turn the ignition switch to ON.

  1. Check for DTCs (COROLLA_ZRE142 RM0000010VK07TX.html).

    OK:
    DTCs B1774 and B1775 are not output.
    HINT:
    Codes other than B1774 and B1775 may be output at this time, but they are not related to this check.


NG
Go to step 7
OK

USE SIMULATION METHOD TO CHECK (COROLLA_ZRE142 RM0000010VJ07XX.html)

7.REPLACE OCCUPANT CLASSIFICATION SENSOR (FRONT SEAT CUSHION ASSEMBLY)

  1. Turn the ignition switch off.

  1. Disconnect the cable from the negative (-) battery terminal.

  1. Replace the front seat cushion assembly (with occupant classification ECU and occupant classification sensor) with a known good part (COROLLA_ZRE142 RM000001Q5I017X.html).

    HINT:
    Perform an inspection using known good parts from another vehicle if possible.

  1. Connect the cable to the negative (-) battery terminal.

  1. Turn the ignition switch to ON.

  1. Clear the DTCs stored in the occupant classification ECU (COROLLA_ZRE142 RM0000010VK07TX.html).

  1. Clear the DTCs stored in the center airbag sensor assembly (COROLLA_ZRE142 RM000000XFE0H1X.html).

  1. Turn the ignition switch off.

  1. Turn the ignition switch to ON.

  1. Check for DTCs (COROLLA_ZRE142 RM0000010VK07TX.html).

    OK:
    DTC B1774 and B1775 are not output.
    HINT:
    Codes other than B1774 and B1775 may be output at this time, but they are not related to this check.

NEXT


8.PERFORM ZERO POINT CALIBRATION

  1. Connect the Techstream to the DLC3.

  1. Turn the ignition switch to ON.

  1. Using the Techstream, perform the zero point calibration (COROLLA_ZRE142 RM0000010VN07SX.html).

  1. Turn the ignition switch off.

  1. Turn the ignition switch to ON.

  1. Clear the DTCs stored in the memory (COROLLA_ZRE142 RM0000010VK07TX.html).

    HINT:
    If the DTCs are not cleared at this time, past DTCs will remain.

NEXT


9.CHECK FOR DTC
HINT:
Check that the zero point calibration is completed normally. If any of the following conditions is met, DTC B1797 will be output (Refer to Initialization: COROLLA_ZRE142 RM0000010VN07SX.html).

  1. Clear the DTCs stored in the center airbag sensor assembly (COROLLA_ZRE142 RM000000XFE0H1X.html).

  1. Turn the ignition switch off.

  1. Turn the ignition switch to ON.

  1. Check for DTCs (COROLLA_ZRE142 RM0000010VK07TX.html).

    OK:
    DTC B1797 is not output.


NG
GO TO DTC B1797 (COROLLA_ZRE142 RM000001PK802UX.html)
OK


10.PERFORM SENSITIVITY CHECK

  1. Perform the sensitivity check (COROLLA_ZRE142 RM0000010VN07SX.html).


NEXT

END