- Occupant classification ECU receives line short circuit signal, open circuit signal, short circuit to ground signal or short circuit to B+ signal in seat position sensor circuit for 2 seconds.
- Seat position sensor malfunction
- Occupant classification ECU malfunction
| Last Modified: 7-3-2017 | 6.8:8.0.40 | Doc ID: RM000001PK4006X |
| Model Year Start: 2007 | Model: LX470 | Prod Date Range: [08/2006 - ] |
| Title: SUPPLEMENTAL RESTRAINT SYSTEM: OCCUPANT CLASSIFICATION SYSTEM: B1772; Seat Position Sensor Circuit Malfunction; 2007 MY LX470 [08/2006 - ] | ||
|
DTC |
B1772 |
Seat Position Sensor Circuit Malfunction |
DESCRIPTION
The seat position sensor circuit consists of the occupant classification ECU and the seat position sensor.
The seat position sensor sends the seat position signal to the occupant classification ECU to control the dual stage deployment of the front passenger airbag.
DTC B1772 is recorded when a malfunction is detected in the seat position sensor circuit.
|
DTC No. |
DTC Detection Condition |
Trouble Area |
|---|---|---|
|
B1772 |
When one of following conditions is met: |
|
NOTICE:
Replace the occupant classification ECU, occupant classification sensor, seat cushion cover pad, seat cushion cover and seat cushion seat heater as a 5 part set (see supply set part no.).
HINT:
- When DTC B1650/32 is detected as a result of troubleshooting the supplemental restraint system, check the DTCs stored in the occupant classification ECU, and perform troubleshooting for those DTCs first.
- Use the intelligent tester to check for DTCs of the occupant classification ECU, otherwise the DTC cannot be read.
WIRING DIAGRAM
INSPECTION PROCEDURE
HINT:
- If troubleshooting (wire harness inspection) is difficult to perform, remove the passenger seat installation bolts to see the undersurface of the seat cushion.
- In the above case, hold the seat so that it does not tip over. Holding the seat up for a long period of time may cause problems, such as seat rail deformation. Hold the seat up only for as long as necessary.
PROCEDURE
|
1. |
CHECK FOR DTC |
(a) Turn the ignition switch ON.
(b)
Clear the DTCs stored in the memory
![2007 MY LX470 [08/2006 - ]; SUPPLEMENTAL RESTRAINT SYSTEM: OCCUPANT CLASSIFICATION SYSTEM: DTC CHECK / CLEAR](../../../../stylegraphics/info.gif "2007 MY LX470 [08/2006 - ]; SUPPLEMENTAL RESTRAINT SYSTEM: OCCUPANT CLASSIFICATION SYSTEM: DTC CHECK / CLEAR")
.
HINT:
First clear DTCs stored in the occupant classification ECU and then in the center airbag sensor.
(c) Turn the ignition switch OFF.
(d) Turn the ignition switch ON.
(e)
Check the DTCs
.
OK:
DTC B1772 is not output.
HINT:
DTCs other than B1772 may be output at this time, but they are not related to this check.
| OK |
|
|
|
2. |
CHECK CONNECTOR |
(a) Turn the ignition 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 seat position sensor.
OK:
The connectors are properly connected.
(d) Disconnect the connectors from the occupant classification ECU and the seat position sensor.
(e) Check that the terminals of the connectors are not damaged.
OK:
The terminals are not deformed or damaged.
HINT:
If the connectors are not connected securely, reconnect the connectors and proceed to the next inspection.
| NG |
|
|
|
3. |
CHECK NO. 1 SEAT WIRE (TO B+) |
|
(a) Disconnect the connectors from the occupant classification ECU and the seat position sensor. |
|
(b) Connect the cable to the negative (-) battery terminal.
(c) Turn the ignition switch ON.
(d) Measure the voltage of the wire harness side connector.
Standard voltage:
|
Tester Connection |
Specified Condition |
|---|---|
|
O5-4 (SP) - Body ground |
Below 1 V |
|
O5-3 (GSP) - Body ground |
Below 1 V |
| NG |
|
|
|
4. |
CHECK NO. 1 SEAT WIRE (FOR OPEN) |
|
(a) Turn the ignition switch OFF. |
|
(b) Disconnect the cable from the negative (-) battery terminal, and wait for at least 90 seconds.
(c) Using a service wire, connect terminals S39-2 (SP) and S39-1 (GSP) of connector C.
NOTICE:
Do not forcibly insert the service wire into the terminals of the connector when connecting.
(d) Measure the resistance of the wire harness side connector.
Standard resistance:
|
Tester Connection |
Specified Condition |
|---|---|
|
O5-4 (SP) - O5-3 (GSP) |
Below 1 Ω |
| NG |
|
|
|
5. |
CHECK NO. 1 SEAT WIRE (TO GROUND) |
|
(a) Disconnect the service wire from connector C. |
|
(b) Measure the resistance of the wire harness side connector.
Standard resistance:
|
Tester Connection |
Specified Condition |
|---|---|
|
O5-4 (SP) - Body ground |
1 MΩ or higher |
|
O5-3 (GSP) - Body ground |
1 MΩ or higher |
| NG |
|
|
|
6. |
CHECK NO. 1 SEAT WIRE (FOR SHORT) |
|
(a) Measure the resistance of the wire harness side connector. Standard resistance:
|
|
| NG |
|
|
|
7. |
CHECK FOR DTC |
(a) Connect the connectors to the occupant classification ECU and the seat position sensor.
(b) Connect the cable to the negative (-) battery terminal.
(c) Turn the ignition switch ON.
(d)
Clear the DTCs stored in the memory
.
HINT:
First clear DTCs stored in the occupant classification ECU and then in the center airbag sensor.
(e) Turn the ignition switch OFF.
(f) Turn the ignition switch ON.
(g)
Check the DTCs
.
OK:
DTC B1772 is not output.
HINT:
DTCs other than B1772 may be output at this time, but they are not related to this check.
| OK |
|
|
|
8. |
REPLACE SEAT POSITION SENSOR |
(a) Turn the ignition switch OFF.
(b) Disconnect the cable from the negative (-) battery terminal, and wait for at least 90 seconds.
(c)
Replace the seat position sensor
.
HINT:
- Perform the inspection using parts from a normal vehicle if possible.
- The seat position sensor is installed on the driver side.
(d) Connect the cable to the negative (-) battery terminal.
(e) Turn the ignition switch ON.
(f)
Clear the DTCs stored in the memory
.
HINT:
First clear DTCs stored in the occupant classification ECU and then in the center airbag sensor.
(g) Turn the ignition switch OFF.
(h) Turn the ignition switch ON.
(i)
Check the DTCs
.
OK:
DTC B1772 is not output.
HINT:
DTCs other than B1772 may be output at this time, but they are not related to this check.
| OK |
|
|
|
9. |
REPLACE OCCUPANT CLASSIFICATION ECU |
(a) Connect the intelligent tester (with CAN VIM) to the DLC3.
(b) Turn the ignition switch ON.
(c)
Store the occupant classification ECU data into the intelligent tester
.
HINT:
If the ECU data cannot be stored in the intelligent tester, replace the front seat cushion (with occupant classification ECU and occupant classification sensor).
(d) Turn the ignition switch OFF.
(e) Disconnect the cable from the negative (-) battery terminal, and wait for at least 90 seconds.
(f)
Replace the occupant classification ECU
.
(g) Connect the cable to the negative (-) battery terminal.
(h) Turn the ignition switch ON.
(i)
Load the data from the previous ECU stored in the tester into the newly installed ECU
.
(j) Turn the ignition switch OFF.
(k) Turn the ignition switch ON.
(l)
Clear the DTCs stored in the memory
.
HINT:
If DTCs are not cleared at this time, past DTCs will remain.
|
|
10. |
PERFORM SENSITIVITY CHECK |
(a)
Perform the sensitivity check
.
| NEXT |
|
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