| Last Modified: 08-21-2023 | 6.11:8.1.0 | Doc ID: RM100000001BKDB |
| Model Year Start: 2019 | Model: Avalon | Prod Date Range: [04/2018 - ] |
| Title: SUPPLEMENTAL RESTRAINT SYSTEMS: OCCUPANT CLASSIFICATION SYSTEM (for Gasoline Model): B1780; Front Occupant Classification Sensor LH Circuit Malfunction; 2019 - 2022 MY Avalon [04/2018 - ] | ||
|
DTC |
B1780 |
Front Occupant Classification Sensor LH Circuit Malfunction |
DESCRIPTION
The front occupant classification sensor LH circuit consists of the occupant detection ECU and front occupant classification sensor LH.
DTC B1780 is stored when a malfunction is detected in the front occupant classification sensor LH circuit.
|
DTC No. |
Detection Item |
DTC Detection Condition |
Trouble Area |
|---|---|---|---|
|
B1780 |
Front Occupant Classification Sensor LH Circuit Malfunction |
|
|
- *: The front occupant classification sensor LH is built into the separate type front seat cushion spring assembly RH.
WIRING DIAGRAM
CAUTION / NOTICE / HINT
NOTICE:
After turning the engine switch off, waiting time may be required before disconnecting the cable from the negative (-) battery terminal. Therefore, make sure to read the disconnecting the cable from the negative (-) battery terminal notices before proceeding with work.
Click here
![2019 - 2022 MY Avalon Avalon HV [04/2018 - ]; INTRODUCTION: REPAIR INSTRUCTION: PRECAUTION](/t3Portal/stylegraphics/info.gif)
HINT:
- When DTC B1650 is stored as a result of troubleshooting for the airbag system, check the DTCs stored in the occupant detection ECU. When DTC B1780 is output, perform troubleshooting for this DTC first.
- If it is difficult to perform troubleshooting (wire harness inspection), remove the front passenger seat installation bolts to see under the seat cushion.
- In the above case, lift and hold the seat so that it does not fall down. Hold the seat only as necessary because holding the seat for a long period of time may cause seat rail deformation.
PROCEDURE
|
1. |
CHECK CONNECTORS |
(a) Turn the engine switch off.
(b) Disconnect the cable from the negative (-) battery terminal.
(c) Check that the connectors are properly connected to the occupant detection ECU and front occupant classification sensor LH.
OK:
The connectors are properly connected.
HINT:
If the connectors are not properly connected, reconnect the connectors and proceed to the next inspection.
(d) Disconnect the connectors from the occupant detection ECU and front occupant classification sensor LH.
(e) Check that the terminals of the connectors are not deformed or damaged.
OK:
The terminals are not deformed or damaged.
| NG |
|
REPLACE FRONT SEAT WIRE RH |
|
|
2. |
CHECK FRONT SEAT WIRE RH |
|
(a) Connect the cable to the negative (-) battery terminal. |
|
(b) Turn the engine switch on (IG).
(c) Measure the voltage according to the value(s) in the table below.
Standard Voltage:
|
Tester Connection |
Condition |
Specified Condition |
|---|---|---|
|
R8-1 (SVC1) - Body ground |
Engine switch on (IG) |
Below 1 V |
|
R8-3 (SIG1) - Body ground |
Engine switch on (IG) |
Below 1 V |
|
R8-5 (SGD1) - Body ground |
Engine switch on (IG) |
Below 1 V |
(d) Turn the engine switch off.
(e) Disconnect the cable from the negative (-) battery terminal.
(f) Using service wires, connect terminals 1 (SVC1) and 3 (SGD1), and terminals 2 (SIG1) and 3 (SGD1) of connector C.
NOTICE:
Do not forcibly insert the service wire into the terminals of the connector when connecting the wire.
(g) Measure the resistance according to the value(s) in the table below.
Standard Resistance:
|
Tester Connection |
Condition |
Specified Condition |
|---|---|---|
|
R8-1 (SVC1) - R8-5 (SGD1) |
Always |
Below 1 Ω |
|
R8-3 (SIG1) - R8-5 (SGD1) |
Always |
Below 1 Ω |
(h) Disconnect the service wires from connector C.
(i) Measure the resistance according to the value(s) in the table below.
Standard Resistance:
|
Tester Connection |
Condition |
Specified Condition |
|---|---|---|
|
R8-1 (SVC1) - R8-5 (SGD1) |
Always |
1 MΩ or higher |
|
R8-3 (SIG1) - R8-5 (SGD1) |
Always |
1 MΩ or higher |
|
R8-1 (SVC1) - R8-3 (SIG1) |
Always |
1 MΩ or higher |
|
R8-1 (SVC1) - Body ground |
Always |
1 MΩ or higher |
|
R8-3 (SIG1) - Body ground |
Always |
1 MΩ or higher |
|
R8-5 (SGD1) - Body ground |
Always |
1 MΩ or higher |
| NG |
|
REPLACE FRONT SEAT WIRE RH |
|
|
3. |
CHECK DTC |
(a) Connect the connectors to the occupant detection ECU and front occupant classification sensor LH.
(b) Connect the cable to the negative (-) battery terminal.
(c) Turn the engine switch on (IG), and wait for at least 60 seconds.
(d) Clear the DTCs stored in the occupant detection ECU.
Body Electrical > Occupant Detection > Clear DTCs
(e) Clear the DTCs stored in the airbag ECU assembly.
Body Electrical > SRS Airbag > Clear DTCs
(f) Turn the engine switch off.
(g) Turn the engine switch on (IG), and wait for at least 10 seconds.
(h) Check for DTCs.
Body Electrical > Occupant Detection > Trouble Codes
OK:
DTC B1780 is not output.
HINT:
Codes other than DTC B1780 may be output at this time, but they are not related to this check.
(i) Turn the engine switch off.
| OK |
|
|
|
4. |
CHECK OCCUPANT DETECTION ECU |
(a) Disconnect the cable from the negative (-) battery terminal.
(b) Replace the occupant detection ECU with a known good one.
Click here
HINT:
Perform the following inspection using known good parts from another vehicle if possible.
(c) Connect the cable to the negative (-) battery terminal.
(d) Turn the engine switch on (IG), and wait for at least 60 seconds.
(e) Clear the DTCs stored in the occupant detection ECU.
Body Electrical > Occupant Detection > Clear DTCs
(f) Clear the DTCs stored in the airbag ECU assembly.
Body Electrical > SRS Airbag > Clear DTCs
(g) Turn the engine switch off.
(h) Turn the engine switch on (IG), and wait for at least 10 seconds.
(i) Check for DTCs.
Body Electrical > Occupant Detection > Trouble Codes
OK:
DTC B1780 is not output.
HINT:
Codes other than DTC B1780 may be output at this time, but they are not related to this check.
(j) Turn the engine switch off.
(k) Disconnect the cable from the negative (-) battery terminal.
(l) Restore the occupant detection ECU that was installed for testing to its original location.
Click here
| NG |
|
|
|
5. |
REPLACE OCCUPANT DETECTION ECU |
(a) Turn the engine switch off.
(b) Disconnect the cable from the negative (-) battery terminal.
(c) Replace the occupant detection ECU with a new one.
Click here
(d) Connect the cable to the negative (-) battery terminal.
|
|
6. |
PERFORM ZERO POINT CALIBRATION |
(a) Using the Techstream, perform Zero Point Calibration.
Click here
| NEXT |
|
END |
|
7. |
REPLACE SEPARATE TYPE FRONT SEAT CUSHION SPRING ASSEMBLY RH |
(a) Turn the engine switch off.
(b) Disconnect the cable from the negative (-) battery terminal.
(c) Replace the separate type front seat cushion spring assembly RH.
Click here
(d) Connect the cable to the negative (-) battery terminal.
|
|
8. |
PERFORM ZERO POINT CALIBRATION |
(a) Using the Techstream, perform Zero Point Calibration.
Click here
| NEXT |
|
END |
|
|