DTC B1774: Pressure Sensor Circuit Malfunction; DTC B1775: Pressure Sensor Power Source Circuit Malfunction: Procedure

1. Turn the power switch ON (IG).
2. Clear the DTCs stored in the occupant classification ECU. Refer to DTC CHECK / CLEAR .
3. Clear the DTCs stored in the center airbag sensor. Refer to DTC CHECK / CLEAR .
4. Turn the power switch OFF.
5. Turn the power switch ON (IG).
6. Check for the DTCs. Refer to DTC CHECK / CLEAR .

   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.

NG → See step   2 

OK → See step   10 

1. Turn the power switch OFF.
2. Disconnect the negative (-) terminal cable from the battery, and wait for at least 90 seconds.
3. Check that the connectors are properly connected to the occupant classification ECU and the occupant detection sensor.

   OK

   Connectors are properly connected.

NG → CONNECT CONNECTORS PROPERLY 

OK: Go to next step 

1. Disconnect the connectors from the occupant classification ECU and the occupant detection sensor.
2. Check that the connectors (on the occupant classification ECU side and occupant detection sensor side) are not damaged.

   OK

   Connectors are not deformed or damaged.

NG → REPAIR OR REPLACE FRONT SEAT WIRE RH 

OK: Go to next step 

Fig 1: Checking Front Seat Wire RH

Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

1. Connect the negative (-) terminal cable to the battery.
2. Turn the power switch ON (IG).
3. Measure the voltage according to the value(s) in the table below.

   Standard voltage

   Tester Connection	Switch Condition	Specified Condition
   a17-6 (PS) - Body ground	Power switch ON (IG)	Below 1 V
   a17-7 (VPS) - Body ground
   a17-15 (GPS) - Body ground

4. Turn the power switch OFF.
5. Disconnect the negative (-) terminal cable from the battery, and wait for at least 90 seconds.
6. Using 2 service wires, connect terminals 1 (GPS) and 3 (VPS), and connect terminals 2 (PS) and 3 (VPS) of connector C.
   NOTE:

   Do not forcibly insert the service wires into the terminals of the connector when connecting the wire.

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

   Standard resistance

   Tester Connection	Switch Condition	Specified Condition
   a17-6 (PS) - a17-7 (VPS)	Always	Below 1 Ω
   a17-7 (VPS) - a17-15 (GPS)

8. Disconnect the service wire from connector C.
9. Measure the resistance according to the value(s) in the table below.

   Standard resistance

   Tester Connection	Switch Condition	Specified Condition
   a17-6 (PS) - Body ground	Always	1 MΩ or higher
   a17-7 (VPS) - Body ground
   a17-15 (GPS) - Body ground
   a17-6 (PS) - a17-15 (GPS)
   a17-7 (VPS) - a17-15 (GPS)

NG → REPAIR OR REPLACE FRONT SEAT WIRE RH 

OK: Go to next step 

1. Connect the connectors to the occupant classification ECU and the occupant detection sensor.
2. Connect the negative (-) terminal cable to the battery.
3. Turn the power switch ON (IG).
4. Clear the DTCs stored in the occupant classification ECU. Refer to DTC CHECK / CLEAR .
5. Clear the DTCs stored in the center airbag sensor. Refer to DTC CHECK / CLEAR .
6. Turn the power switch OFF.
7. Turn the power switch ON (IG).
8. Check for the DTCs. Refer to DTC CHECK / CLEAR .

   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 → See step   6 

OK → See step   10 

1. Turn the power switch OFF.
2. Disconnect the negative (-) terminal cable from the battery, and wait for at least 90 seconds.
3. Replace the front seat cushion (with occupant classification ECU and occupant detection sensor). Refer to DISASSEMBLY .

   HINT: 

   Perform the inspection using parts from a normal vehicle if possible.

4. Connect the negative (-) terminal cable to the battery.
5. Turn the power switch ON (IG).
6. Clear the DTCs stored in the occupant classification ECU. Refer to DTC CHECK / CLEAR .
7. Clear the DTCs stored in the center airbag sensor. Refer to DTC CHECK / CLEAR
8. Turn the power switch OFF.
9. Turn the power switch ON (IG).
10. Check for the DTCs. Refer to DTC CHECK / CLEAR .

    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: Go to next step 

1. Connect the Techstream to the DLC3.
2. Turn the power switch ON (IG).
3. Using the Techstream, perform the zero point calibration. Refer to INITIALIZATION .
4. Turn the power switch OFF.
5. Turn the power switch ON (IG).
6. Clear the DTCs stored in the memory. Refer to DTC CHECK / CLEAR .

   HINT: 

   If DTC is not cleared at this time, past DTC will remain.

NEXT: Go to next step 

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. Refer to INITIALIZATION ):

• Zero point calibration is performed when the conditions for the calibration are not satisfied.
• Zero point calibration has failed.

1. Turn the power switch ON (IG).
2. Clear the DTCs stored in the occupant classification ECU. Refer to DTC CHECK / CLEAR .
3. Clear the DTCs stored in the center airbag sensor. Refer to DTC CHECK / CLEAR .
4. Turn the power switch OFF.
5. Turn the power switch ON (IG).
6. Check for the DTCs. Refer to DTC CHECK / CLEAR .

   OK

   DTC B1797 is not output.

NG → See step   11 

OK: Go to next step 

1. Perform the sensitivity check. Refer to INITIALIZATION .

NEXT → END