DESCRIPTION
The front occupant classification sensor RH circuit consists of the occupant detection ECU and the front occupant classification sensor RH.
DTC B1781 is set when a malfunction is detected in the front occupant classification sensor RH circuit.
DTC No. |
DTC Detecting Conditions |
Trouble Areas |
---|---|---|
B1781 |
|
|
HINT:
WIRING DIAGRAM
CAUTION / NOTICE / HINT
HINT:
PROCEDURE
1. |
CHECK DTC |
(a) Turn the ignition switch to the ON position.
(b) Clear any DTCs stored in the memory (See page ).
HINT:
(c) Turn the ignition switch to the LOCK position.
(d) Turn the ignition switch to the ON position.
(e) Using the Techstream, check for DTCs of the occupant detection ECU (See page ).
OK:
DTC B1781 is not output.
HINT:
DTCs other than B1781 may be output at this time, but they are not related to this check.
OK |
USE SIMULATION METHOD TO CHECK |
|
2. |
CHECK CONNECTION OF CONNECTORS |
(a) Turn the ignition switch to the LOCK position.
(b) Disconnect the negative (-) terminal cable from the battery, and wait for at least 90 seconds.
(c) Check that the connectors are properly connected to the occupant detection ECU and the front occupant classification sensor RH.
OK:
The connectors are properly connected.
NG |
OTHERS CONNECTORS |
|
3. |
CHECK CONNECTORS |
(a) Check that the connectors (on the occupant detection ECU side and front occupant classification sensor RH side) are not damaged (See page ).
OK:
The connectors are not deformed or damaged.
NG |
REPAIR OR REPLACE WIRE HARNESS |
|
4. |
CHECK NO. 1 SEAT WIRE (TO B+) |
(a) Disconnect the connectors from the occupant detection ECU and the front occupant classification sensor RH. |
|
(b) Connect the negative (-) terminal cable to the battery.
(c) Turn the ignition switch to the ON position.
(d) Measure the voltage.
Standard voltage:
Tester Connection |
Condition |
Specified Condition |
---|---|---|
O4-2 (SGD2) - Body ground |
Ignition switch ON |
Below 1 V |
O4-8 (SIG2) - Body ground |
Ignition switch ON |
Below 1 V |
O4-12 (SVC2) - Body ground |
Ignition switch ON |
Below 1 V |
NG |
REPAIR OR REPLACE NO. 1 SEAT WIRE |
|
5. |
CHECK NO. 1 SEAT WIRE (FOR OPEN) |
(a) Turn the ignition switch to the LOCK position. |
|
(b) Disconnect the negative (-) terminal cable from the battery, and wait for at least 90 seconds.
(c) Using service wires, connect O7-1 (SVC2) and O7-3 (SGD2), and connect O7-2 (SIG2) and O7-3 (SGD2) of connector C.
NOTICE:
Do not forcibly insert the service wires into the terminals of the connector when connecting.
(d) Measure the resistance.
Standard resistance:
Tester Connection |
Condition |
Specified Condition |
---|---|---|
O4-8 (SIG2) - O4-2 (SGD2) |
Always |
Below 1 Ω |
O4-12 (SVC2) - O4-2 (SGD2) |
Always |
Below 1 Ω |
NG |
REPAIR OR REPLACE NO. 1 SEAT WIRE |
|
6. |
CHECK NO. 1 SEAT WIRE (FOR SHORT) |
(a) Disconnect the service wires from connector C. |
|
(b) Measure the resistance.
Standard resistance:
Tester Connection |
Condition |
Specified Condition |
---|---|---|
O4-8 (SIG2) - O4-2 (SGD2) |
Always |
1 MΩ or higher |
O4-12 (SVC2) - O4-2 (SGD2) |
Always |
1 MΩ or higher |
O4-8 (SIG2) - O4-12 (SVC2) |
Always |
1 MΩ or higher |
NG |
REPAIR OR REPLACE NO. 1 SEAT WIRE |
|
7. |
CHECK NO. 1 SEAT WIRE (TO GROUND) |
(a) Measure the resistance. Standard resistance:
|
|
NG |
REPAIR OR REPLACE NO. 1 SEAT WIRE |
|
8. |
CHECK DTC |
(a) Connect the connectors to the occupant detection ECU and the front occupant classification sensor RH.
(b) Connect the negative (-) terminal cable to the battery.
(c) Turn the ignition switch to the ON position.
(d) Clear any DTCs stored in the memory (See page ).
HINT:
(e) Turn the ignition switch to the LOCK position.
(f) Turn the ignition switch to the ON position.
(g) Using the Techstream, check for DTCs of the occupant detection ECU (See page ).
OK:
DTC B1781 is not output.
HINT:
DTCs other than B1781 may be output at this time, but they are not related to this check.
OK |
USE SIMULATION METHOD TO CHECK |
|
9. |
REPLACE OCCUPANT DETECTION ECU |
(a) Turn the ignition switch to the LOCK position.
(b) Disconnect the negative (-) terminal cable from the battery, and wait for at least 90 seconds.
(c) Replace the occupant detection ECU (See page ).
HINT:
Perform the inspection using parts from a normal vehicle when possible.
|
10. |
PERFORM ZERO POINT CALIBRATION |
(a) Connect the negative (-) terminal cable to the battery.
(b) Connect the Techstream to the DLC3.
(c) Turn the ignition switch to the ON position.
(d) Using the Techstream, perform the zero point calibration (See page ).
OK:
"Zero Point Calibration is complete." is displayed on the Techstream.
NG |
GO TO STEP 13 |
|
11. |
PERFORM SENSITIVITY CHECK |
(a) Using the Techstream, perform the sensitivity check (See page ).
Standard value:
27 to 33 kg (59.52 to 72.75 lb)
NG |
GO TO STEP 13 |
|
12. |
CHECK DTC |
(a) Connect the negative (-) terminal cable to the battery.
(b) Turn the ignition switch to the ON position.
(c) Clear any DTCs stored in the memory (See page ).
HINT:
(d) Turn the ignition switch to the LOCK position.
(e) Turn the ignition switch to the ON position.
(f) Using the Techstream, check for DTCs of the occupant detection ECU (See page ).
OK:
DTC B1781 is not output.
HINT:
DTCs other than B1781 may be output at this time, but they are not related to this check.
OK |
USE SIMULATION METHOD TO CHECK |
|
13. |
REPLACE FRONT SEAT WITH ADJUSTER FRAME ASSEMBLY RH |
(a) Turn the ignition switch to the LOCK position.
(b) Disconnect the negative (-) terminal cable from the battery, and wait for at least 90 seconds.
(c) Replace the front seat with adjuster frame assembly RH (See page ).
|
14. |
PERFORM ZERO POINT CALIBRATION |
(a) Connect the negative (-) terminal cable to the battery.
(b) Connect the Techstream to the DLC3.
(c) Turn the ignition switch to the ON position.
(d) Using the Techstream, perform the zero point calibration (See page ).
OK:
"Zero Point Calibration is complete." is displayed on the Techstream.
|
15. |
PERFORM SENSITIVITY CHECK |
(a) Using the Techstream, perform the sensitivity check (See page ).
Standard value:
27 to 33 kg (59.52 to 72.75 lb)
NEXT |
USE SIMULATION METHOD TO CHECK |
Problem Symptoms Table
PROBLEM SYMPTOMS TABLE
HINT:
Use the table below to help determine the cause of problem symptoms.
If multiple suspected areas are listed, the potential causes of the symptoms
are listed in order of probability in the "Suspected Area" column of the
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Precaution
PRECAUTION
1. EXPRESSIONS OF IGNITION SWITCH
HINT:
The type of ignition switch used on this model differs according to the specifications
of the vehicle. The expressions listed in the table below are used in this section.
Expression
Ignition Switch
(Position)
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