B1771

SUPPLEMENTAL RESTRAINT SYSTEM: OCCUPANT CLASSIFICATION SYSTEM: B1771: Passenger Side Buckle Switch Circuit Malfunction
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 assembly RH.

DTC B1771 is recorded when a malfunction is detected in the passenger side buckle switch circuit.

Troubleshoot DTC B1771 first when the DTC B1771 and B1795 are output simultaneously.





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 B1771 in output, perform troubleshooting for the DTC.

WIRING DIAGRAM





INSPECTION PROCEDURE

HINT
* If troubleshooting (wire harness inspection) is difficult to perform, remove the front passenger seat installation bolts to see the under surface of seat cushion.
* In the above case, hold the seat so that it does not fall down. Holding the seat for a long period of time may cause a problem, such as seat rail deformation. Hold the seat only as necessary.

PROCEDURE

1. CHECK DTC

(a) Turn the ignition switch on (IG).

(b) Clear the DTCs stored in the occupant classification ECU Reading and Clearing Diagnostic Trouble Codes.

(c) for TMC made:

Clear the DTCs stored in the center airbag sensor assembly Airbag System (for TMC Made).

(d) except TMC made:

Clear the DTCs stored in the center airbag sensor assembly Airbag System (except TMC Made).

(e) Turn the ignition switch off.

(f) Turn the ignition switch on (IG).

(g) Check the 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.

OK -- USE SIMULATION METHOD TO CHECK Diagnosis System
NG -- Continue to next step.

2. CHECK CONNECTION OF CONNECTORS

(a) Turn the ignition switch off.

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

(c) Check that the connectors are properly connected to the occupant classification ECU and the front seat inner belt assembly RH.

OK:

The connectors are properly connected.

NG -- CONNECT CONNECTORS PROPERLY, THEN GO TO STEP 1
OK -- Continue to next step.

3. CHECK WIRE HARNESS (SHORT TO B+)

(a) Disconnect the connectors from the occupant classification ECU and the front seat inner belt assembly RH.





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

(c) Turn the ignition switch on (IG).

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

Standard voltage:

for Power seat
for Manual seat
Result














B -- REPAIR OR REPLACE FLOOR WIRE NO. 2

A -- REPAIR OR REPLACE FRONT SEAT WIRE RH
C -- Continue to next step.

4. CHECK WIRE HARNESS (OPEN)

(a) Turn the ignition switch off.





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

(c) Using a service wire, connect terminals 2 and 1 of connector C.

NOTICE:
Do not forcibly insert a service wire into the terminals of the connector when connecting.

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

Standard resistance:

for Power seat
for Manual seat
Result














B -- REPAIR OR REPLACE FLOOR WIRE NO. 2

A -- REPAIR OR REPLACE FRONT SEAT WIRE RH
C -- Continue to next step.

5. CHECK WIRE HARNESS (SHORT)

(a) Disconnect the service wire from connector C.





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

Standard resistance:

for Power seat
for Manual seat
Result














B -- REPAIR OR REPLACE FLOOR WIRE NO. 2

A -- REPAIR OR REPLACE FRONT SEAT WIRE RH
C -- Continue to next step.

6. CHECK WIRE HARNESS (SHORT TO GROUND)

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





Standard resistance:

for Power seat
for Manual seat
Result














B -- REPAIR OR REPLACE FLOOR WIRE NO. 2

A -- REPAIR OR REPLACE FRONT SEAT WIRE RH
C -- Continue to next step.

7. CHECK DTC

(a) Connect the connectors to the occupant classification ECU and the front seat inner belt assembly RH.

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

(c) Turn the ignition switch on (IG).

(d) Clear the DTCs stored in the occupant classification ECU Reading and Clearing Diagnostic Trouble Codes.

(e) for TMC made:

Clear the DTCs stored in the center airbag sensor assembly Airbag System (for TMC Made).

(f) except TMC made:

Clear the DTCs stored in the center airbag sensor assembly Airbag System (except TMC Made).

(g) Turn the ignition switch off.

(h) Turn the ignition switch on (IG).

(i) Check the 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.

OK -- USE SIMULATION METHOD TO CHECK Diagnosis System
NG -- Continue to next step.

8. REPLACE FRONT SEAT INNER BELT ASSEMBLY RH

(a) Turn the ignition switch off.

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

(c) Replace the front seat inner belt assembly RH Removal.

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

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

(e) Turn the ignition switch on (IG).

(f) Clear the DTCs stored in the occupant classification ECU Reading and Clearing Diagnostic Trouble Codes.

(g) for TMC made:

Clear the DTCs stored in the center airbag sensor assembly Airbag System (for TMC Made).

(h) except TMC made:

Clear the DTCs stored in the center airbag sensor assembly Airbag System (except TMC Made).

(i) Turn the ignition switch off.

(j) Turn the ignition switch on (IG).

(k) Check the 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.

OK -- END
NG -- Continue to next step.

9. REPLACE OCCUPANT CLASSIFICATION ECU

(a) Turn the ignition switch off.

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

(c) Replace the occupant classification ECU Removal.

NEXT -- Continue to next step.

10. PERFORM ZERO POINT CALIBRATION

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

(b) Connect Techstream to the DLC3.

(c) Turn the ignition switch on (IG).

(d) Using Techstream, perform "zero point calibration" Programming and Relearning.

OK:

"Zero Point Calibration is complete." is displayed.

NEXT -- Continue to next step.

11. PERFORM SENSITIVITY CHECK

(a) Using Techstream, perform "sensitivity check" Programming and Relearning.

Standard value:

27 to 33 kg (59.52 to 72.75 lb)

NEXT -- END