- The occupant classification ECU receives a line short circuit signal, open circuit signal, short circuit to ground signal or short circuit to B+ signal in the occupant detection sensor circuit for 2 seconds.
- An occupant detection sensor malfunction.
- An occupant classification ECU malfunction.
| Last Modified: 11-27-2007 | 1.6 C | |
| Service Category: Vehicle Interior | Section: Supplemental Restraint Systems | |
| Model Year: 2008 | Model: LX570 | Doc ID: RM000001PK600WX |
| Title: SUPPLEMENTAL RESTRAINT SYSTEMS: OCCUPANT CLASSIFICATION SYSTEM: DESCRIPTION (2008 LX570) | ||
|
DTC |
B1774 |
Pressure Sensor Circuit Malfunction |
|
DTC |
B1775 |
Pressure Sensor Power Source Circuit Malfunction |
DESCRIPTION
The pressure sensor circuit consists of the occupant classification ECU and the occupant detection sensor.
The occupant detection sensor sends the pressure signal to the occupant classification ECU.
DTC B1774 and B1775 are stored when a malfunction is detected in the pressure sensor circuit.
|
DTC Code |
DTC Detection Condition |
Trouble Area |
|---|---|---|
|
B1774 B1775 |
When one of the following conditions is met: |
|
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 B1774 and B1775 are output, perform troubleshooting for those DTCs first.
WIRING DIAGRAM
INSPECTION PROCEDURE
NOTICE:
-
w/ Navigation system:
After the engine switch is turned off, the HDD navigation system requires approximately 6 minutes to record various types of memory and settings. As a result, after turning the engine switch off, wait 6 minutes or more before disconnecting the cable from the negative (-) battery terminal.
-
When disconnecting the cable from the negative (-) battery terminal while performing repairs, some systems need to be initialized after the cable is reconnected
.
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 fall down.
- After performing the zero point calibration, check for DTCs to confirm that the calibration is completed normally (if it fails, DTC B1797 will be output).
PROCEDURE
|
1. |
CHECK FOR DTC |
(a) Turn the engine switch on (IG).
(b) Clear the DTCs stored in the occupant classification ECU
.
(c) Clear the DTCs stored in the center airbag sensor
.
(d) Turn the engine switch off.
(e) Turn the engine switch on (IG).
(f) Check for DTCs
.
OK:
DTC B1774 and B1775 are not output.
HINT:
Codes other than DTC B1774 and B1775 may be output at this time, but they are not related to this 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 occupant detection sensor.
OK:
Connectors are properly connected.
|
|
3. |
CHECK CONNECTOR |
(a) Disconnect the connectors from the occupant classification ECU and the occupant detection sensor.
(b) Check that the connectors (on the center airbag sensor and occupant detection sensor side) are not damaged.
OK:
Connectors are not deformed or damaged.
|
|
4. |
CHECK FRONT SEAT WIRE RH (OCCUPANT DETECTION SENSOR - 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:
|
Tester Connection |
Switch Condition |
Specified Condition |
|---|---|---|
|
c8-6 (PS) - Body ground |
Engine switch on (IG) |
Below 1 V |
|
c8-7 (VPS) - Body ground |
||
|
c8-15 (GPS) - Body ground |
(d) Turn the engine switch off.
(e) Disconnect the cable from the negative (-) battery terminal, and wait for at least 90 seconds.
(f) Using 2 service wires, connect terminals 1 (GPS) and 3 (VPS), and connect terminals 2 (PS) and 3 (VPS) of connector C.
NOTICE:
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:
|
Tester Connection |
Condition |
Specified Condition |
|---|---|---|
|
c8-6 (PS) - c8-7 (VPS) |
Always |
Below 1 Ω |
|
c8-7 (VPS) - c8-15 (GPS) |
(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 |
|---|---|---|
|
c8-6 (PS) - Body ground |
Always |
1 MΩ or higher |
|
c8-7 (VPS) - Body ground |
||
|
c8-15 (GPS) - Body ground |
||
|
c8-6 (PS) - c8-15 (GPS) |
||
|
c8-7 (VPS) - c8-15 (GPS) |
|
|
5. |
CHECK FOR DTC |
(a) Connect the connectors to the occupant classification ECU and the occupant detection sensor.
(b) Connect the cable to the negative (-) battery terminal.
(c) Turn the engine switch on (IG).
(d) Clear the DTCs stored in the occupant classification ECU
.
(e) Clear the DTCs stored in the center airbag sensor
.
(f) Turn the engine switch off.
(g) Turn the engine switch on (IG).
(h) Check for DTCs
.
OK:
DTC B1774 and B1775 are not output.
HINT:
Codes other than DTC B1774 and B1775 may be output at this time, but they are not related to this check.
|
|
6. |
REPLACE NO. 1 SEAT CUSHION ASSEMBLY (OCCUPANT CLASSIFICATION ECU AND OCCUPANT DETECTION SENSOR) |
(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
.
(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 and occupant detection sensor)
.
(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
.
(j) Turn the engine switch off.
(k) Turn the engine switch on (IG).
(l) Clear the DTCs stored in the memory
.
HINT:
If the DTCs are not cleared at this time, past DTCs will remain.
|
|
7. |
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
.
(d) Turn the engine switch off.
(e) Turn the engine switch on (IG).
(f) Clear the DTCs stored in the memory
.
HINT:
If DTCs are not cleared at this time, past DTCs will remain.
|
|
8. |
CHECK FOR DTC |
HINT:
Check that the zero point calibration is completed normally. If one of the following conditions is met, DTC B1797 will be output (refer to Initialization
):
- Zero point calibration is performed when the conditions for the calibration are not satisfied.
- Zero point calibration has failed.
(a) Turn the engine switch on (IG).
(b) Clear the DTCs stored in the occupant classification ECU
.
(c) Clear the DTCs stored in the center airbag sensor
.
(d) Turn the engine switch off.
(e) Turn the engine switch on (IG).
(f) Check for DTCs
.
OK:
DTC B1797 is not output.
HINT:
Codes other than DTC B1797 may be output at this time, but they are not related to this check.
|
|
9. |
PERFORM SENSITIVITY CHECK |
(a) Perform the sensitivity check
.
|
|
|