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B1771








SUPPLEMENTAL RESTRAINT SYSTEMS: OCCUPANT CLASSIFICATION SYSTEM: B1771: Passenger Side Buckle Switch Circuit Malfunction

DTC B1771 - Passenger Side Buckle Switch Circuit Malfunction

DESCRIPTION

The passenger side buckle switch circuit consists of the occupant classification ECU and the front seat inner belt RH.
DTC B1771 is stored when a malfunction is detected in the passenger side buckle switch circuit.





HINT: When DTC B1650 is stored as a result of troubleshooting for the "Airbag System", check the DTCs stored in the occupant classification ECU. When DTC B1771 is output, perform troubleshooting for it first.

WIRING DIAGRAM





INSPECTION PROCEDURE
HINT:
- If troubleshooting (wire harness inspection) is difficult to perform, remove the front passenger seat installation bolts to see the undersurface of the seat cushion.
- In the above case, hold the seat so that it does not fall down.

PROCEDURE

1. CHECK FOR DTC
(a) Turn the engine switch on (IG).
(b) Clear the DTCs stored in the occupant classification ECU. Reading and Clearing Diagnostic Trouble Codes
(c) Clear the DTCs stored in the center airbag sensor. DTC Check / Clear
(d) Turn the engine switch off.
(e) Turn the engine switch on (IG).
(f) Check for DTCs. Reading and Clearing Diagnostic Trouble Codes
OK:
DTC B1771 is not output.
HINT: Codes other than B1771 may be output at this time, but they are not related to this check.

NG -- CHECK CONNECTION OF CONNECTOR
OK -- USE SIMULATION METHOD TO CHECK
2. CHECK CONNECTION OF CONNECTOR
(a) Turn the engine switch off.
(b) Disconnect the cable from the negative (-) battery terminal, and wait for at least 90 seconds.
(c) Check that the connectors are properly connected to the occupant classification ECU and the front seat inner belt RH.
OK:
Connectors are properly connected.
NG -- CONNECT CONNECTORS PROPERLY
OK -- Continue to next step.
3. CHECK CONNECTOR
(a) Disconnect the connectors from the occupant classification ECU and front seat inner belt RH.
(b) Check that the connectors (on the center airbag sensor side and front seat inner belt RH side) are not damaged.
OK:
Connectors are not deformed or damaged.
HINT: If the connectors are not connected securely, reconnect the connectors and proceed to the next inspection.

NG -- REPLACE FRONT SEAT WIRE RH
OK -- Continue to next step.
4. CHECK FRONT SEAT WIRE RH (FRONT SEAT INNER BELT RH - OCCUPANT CLASSIFICATION ECU)





(a) Connect the cable to the negative (-) battery terminal, and wait for at least 2 seconds.
(b) Turn the engine switch on (IG).
(c) Measure the voltage according to the value(s) in the table below.
Standard Voltage:





(d) Turn the engine switch off.
(e) Disconnect the cable from the negative (-) battery terminal, and wait for at least 90 seconds.
(f) Using a service wire, connect terminals 1 (RBE+) and 2 (RBE-) of connector C.
NOTE: Do not forcibly insert the service wire into the terminals of the connector when connecting a service wire.
(g) Measure the resistance according to the value(s) in the table below.
Standard Resistance:





(h) Disconnect the service wire from connector C.
(i) Measure the resistance according to the value(s) in the table below.
Standard Resistance:






NG -- REPLACE FRONT SEAT WIRE RH
OK -- Continue to next step.
5. CHECK FOR DTC
(a) Connect the connectors to the occupant classification ECU and the front seat inner belt RH.
(b) Connect the cable to the negative (-) battery terminal, and wait for at least 2 seconds.
(c) Turn the engine switch on (IG).
(d) Clear the DTCs stored in the occupant classification ECU. Reading and Clearing Diagnostic Trouble Codes
(e) Clear the DTCs stored in the center airbag sensor. DTC Check / Clear
(f) Turn the engine switch off.
(g) Turn the engine switch on (IG).
(h) Check for DTCs. Reading and Clearing Diagnostic Trouble Codes
OK:
DTC B1771 is not output.
HINT: Codes other than DTC B1771 may be output at this time, but they are not related to this check.

NG -- REPLACE FRONT SEAT INNER BELT ASSEMBLY RH (PASSENGER SIDE BUCKLE SWITCH)
OK -- USE SIMULATION METHOD TO CHECK
6. REPLACE FRONT SEAT INNER BELT ASSEMBLY RH (PASSENGER SIDE BUCKLE SWITCH)
(a) Turn the engine switch off.
(b) Disconnect the cable from the negative (-) battery terminal, and wait for at least 90 seconds.
(c) Replace the front seat inner belt RH.
HINT: Perform the inspection using parts from a normal vehicle if possible.
(d) Connect the cable to the negative (-) battery terminal, and wait for at least 2 seconds.
(e) Turn the engine switch on (IG).
(f) Clear the DTCs stored in the occupant classification ECU. Reading and Clearing Diagnostic Trouble Codes
(g) Clear the DTCs stored in the center airbag sensor. DTC Check / Clear
(h) Turn the engine switch off.
(i) Turn the engine switch on (IG).
(j) Check for DTCs. Reading and Clearing Diagnostic Trouble Codes
OK:
DTC B1771 is not output.
HINT: Codes other than DTC B1771 may be output at this time, but they are not related to this check.

NG -- REPLACE NO. 1 SEAT CUSHION ASSEMBLY (OCCUPANT CLASSIFICATION ECU)
OK -- END
7. REPLACE NO. 1 SEAT CUSHION ASSEMBLY (OCCUPANT CLASSIFICATION ECU)
(a) Connect the Techstream to the DLC3.
(b) Turn the engine switch on (IG).
(c) Using the Techstream, save the ECU data from the ECU which is installed in the vehicle. Registration
(d) Turn the engine switch off.
(e) Disconnect the cable from the negative (-) battery terminal, and wait for at least 90 seconds.
(f) Replace the No. 1 seat cushion (occupant classification ECU).
(g) Connect the cable to the negative (-) battery terminal, and wait for at least 2 seconds.
(h) Turn the engine switch on (IG).
(i) Using the Techstream, load the previous ECU data stored in the Techstream into the new ECU. Registration
(j) Turn the engine switch off.
(k) Turn the engine switch on (IG).
(l) Clear the DTCs stored in the memory. Reading and Clearing Diagnostic Trouble Codes
HINT: If DTCs are not cleared at this time, past DTCs will remain.

NEXT -- Continue to next step.
8. PERFORM ZERO POINT CALIBRATION
(a) Connect the Techstream to the DLC3.
(b) Turn the engine switch on (IG).
(c) Using the Techstream, perform zero point calibration. Initialization
(d) Turn the engine switch off.
(e) Turn the engine switch on (IG).
(f) Clear the DTCs stored in the occupant classification ECU. Reading and Clearing Diagnostic Trouble Codes
HINT: If the DTCs are not cleared at this time, past DTCs will remain.

NEXT -- Continue to next step.
9. PERFORM SENSITIVITY CHECK
(a) Perform the sensitivity check. Initialization
NEXT -- END
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