- Occupant classification ECU receives line short circuit signal, open circuit signal, short circuit to ground signal or short circuit to +B signal in center airbag sensor communication circuit for 2 seconds
- Center airbag sensor malfunction
- Occupant classification ECU malfunction
| Last Modified: 11-29-2007 | 1.6 C | |
| Service Category: Vehicle Interior | Section: Supplemental Restraint Systems | |
| Model Year: 2008 | Model: Sequoia | Doc ID: RM00000158000JX |
| Title: SUPPLEMENTAL RESTRAINT SYSTEMS: OCCUPANT CLASSIFICATION SYSTEM: DESCRIPTION (2008 Sequoia) | ||
|
DTC |
B1790 |
Center Airbag Sensor Assembly Communication Circuit Malfunction |
DESCRIPTION
The center airbag sensor communication circuit consists of the occupant classification ECU and the center airbag sensor.
DTC B1790 is stored when a malfunction is detected in the center airbag sensor communication circuit.
|
DTC Code |
DTC Detection Condition |
Trouble Area |
|---|---|---|
|
B1790 |
One of following conditions is met: |
|
HINT:
- When DTC B1630/32 is detected as a result of troubleshooting the airbag system, perform troubleshooting for DTC B1790 of the occupant classification system.
- Use the Techstream to check for DTCs of the occupant classification ECU, otherwise the DTCs cannot be read.
WIRING DIAGRAM
INSPECTION PROCEDURE
NOTICE:
After the ignition switch is turned off, the navigation system requires approximately 90 seconds to record various types of memory and settings. As a result, after turning the ignition switch off, wait 90 seconds or more before disconnecting the cable from the negative (-) battery terminal.
HINT:
- If troubleshooting (wire harness inspection) is difficult to perform, remove the front RH 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. Holding the seat 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 to ON, and wait for at least 60 seconds.
(b) Clear any DTCs stored in the memory
.
HINT:
- First clear DTCs stored in the occupant classification ECU and then in the center airbag sensor.
- Use the Techstream to clear the DTCs of the occupant classification ECU, otherwise the DTCs cannot be cleared.
(c) Turn the ignition switch off.
(d) Turn the ignition switch to ON, and wait for at least 60 seconds.
(e) Using the Techstream, check for DTCs of the occupant classification ECU
.
OK:
DTC B1790 is not output.
HINT:
DTCs other than DTC B1790 may be output at this time, but they are not related to this check.
|
|
2. |
CHECK CONNECTION OF 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 center airbag sensor.
OK:
Connectors are properly connected.
|
|
3. |
CHECK CONNECTOR |
(a) Check that the connectors (on the center airbag sensor side and occupant classification ECU side) are not damaged
.
OK:
Connectors are not deformed or damaged.
Result
|
Result |
Proceed to |
|---|---|
|
Connectors are not deformed or damaged (for Power seat) |
A |
|
Connectors are not deformed or damaged (for Manual seat) |
B |
|
Connectors are deformed or damaged |
C |
|
|
4. |
CHECK OCCUPANT CLASSIFICATION SYSTEM CIRCUIT |
(a) Connect the cable to the negative (-) battery terminal, and wait for at least 2 seconds.
(b) Turn the ignition switch to ON, and wait for at least 60 seconds.
(c) Measure the voltage according to the value(s) in the table below.
Standard Voltage:
|
Tester Connection |
Switch Condition |
Specified Condition |
|---|---|---|
|
W6-8 (FSR+) - Body ground |
Ignition switch ON |
Below 1 V |
|
W6-4 (FSR-) - Body ground |
(d) Turn the ignition switch off.
(e) Disconnect the cable from the negative (-) battery terminal, and wait for at least 90 seconds.
(f) Using a service wire, connect terminals 12 (FSP+) and 13 (FSP-) of connector B.
NOTICE:
Do not forcibly insert the service wire into the terminals of the connector.
(g) Measure the resistance according to the value(s) in the table below.
Standard Resistance:
|
Tester Connection |
Condition |
Specified Condition |
|---|---|---|
|
W6-8 (FSR+) - W6-4 (FSR-) |
Always |
Below 1 Ω |
(h) Disconnect the service wire from connector B.
(i) Measure the resistance according to the value(s) in the table below.
Standard Resistance:
|
Tester Connection |
Condition |
Specified Condition |
|---|---|---|
|
W6-8 (FSR+) - W6-4 (FSR-) |
Always |
1 MΩ or higher |
|
W6-8 (FSR+) - Body ground |
||
|
W6-4 (FSR-) - Body ground |
|
|
5. |
CHECK FOR DTC |
(a) Connect the connectors to the occupant classification ECU and the center airbag sensor.
(b) Connect the cable to the negative (-) battery terminal, and wait for at least 2 seconds.
(c) Turn the ignition switch to ON, and wait for at least 60 seconds.
(d) Clear any DTCs stored in the memory
.
HINT:
- First clear any DTCs stored in the occupant classification ECU and then in the center airbag sensor.
- Use the Techstream to clear the DTCs of the occupant classification ECU, otherwise the DTCs cannot be cleared.
(e) Turn the ignition switch off.
(f) Turn the ignition switch to ON, and wait for at least 60 seconds.
(g) Using the Techstream, check for DTCs of the occupant classification ECU
.
OK:
DTC B1790 is not output.
HINT:
DTCs other than DTC B1790 may be output at this time, but they are not related to this check.
|
|
6. |
REPLACE OCCUPANT CLASSIFICATION ECU |
(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 occupant classification ECU
.
HINT:
Perform the inspection using parts from a normal vehicle when possible.
|
|
7. |
PERFORM ZERO POINT CALIBRATION |
(a) Connect the cable to the negative (-) battery terminal, and wait for at least 2 seconds.
(b) Connect the Techstream to the DLC3.
(c) Turn the ignition switch to ON, and wait for at least 60 seconds.
(d) Using the Techstream, perform the zero point calibration
.
|
|
8. |
PERFORM SENSITIVITY CHECK |
(a) Using the Techstream, perform the sensitivity check
.
Standard range:
27 to 33 kg (59.5 to 72.8 lb)
|
|
9. |
CHECK FOR DTC |
(a) Connect the connector to the occupant classification ECU.
(b) Connect the cable to the negative (-) battery terminal, and wait for at least 2 seconds.
(c) Turn the ignition switch to ON, and wait for at least 60 seconds.
(d) Clear any DTCs stored in the memory
.
HINT:
- First clear DTCs stored in the occupant classification ECU and then in the center airbag sensor.
- Use the Techstream to clear the DTCs of the occupant classification ECU, otherwise the DTCs cannot be cleared.
(e) Turn the ignition switch off.
(f) Turn the ignition switch to ON, and wait for at least 60 seconds.
(g) Using the Techstream, check for DTCs of the occupant classification ECU
.
OK:
DTC B1790 is not output.
HINT:
DTCs other than DTC B1790 may be output at this time, but they are not related to this check.
|
|
10. |
CHECK FRONT SEAT WIRE RH |
|
(a) Disconnect the front seat wire RH connector from the No. 2 floor wire. |
(b) Connect the cable to the negative (-) battery terminal, and wait for at least 2 seconds.
(c) Turn the ignition switch to ON, and wait for at least 60 seconds.
(d) Measure the voltage according to the value(s) in the table below.
Standard Voltage:
|
Tester Connection |
Switch Condition |
Specified Condition |
|---|---|---|
|
PW1-8 (FSP+) - Body ground |
Ignition switch ON |
Below 1 V |
|
PW1-9 (FSP-) - Body ground |
(e) Turn the ignition switch off.
(f) Disconnect the connector from the occupant classification ECU.
(g) Using a service wire, connect terminals 8 (FSR+) and 4 (FSR-) of connector E.
NOTICE:
Do not forcibly insert the service wire into the terminals of connector.
(h) Measure the resistance according to the value(s) in the table below.
Standard Resistance:
|
Tester Connection |
Condition |
Specified Condition |
|---|---|---|
|
PW1-8 (FSP+) - PW1-9 (FSP-) |
Always |
Below 1 Ω |
(i) Disconnect the service wire from connector E.
(j) Measure the resistance according to the value(s) in the table below.
Standard Resistance:
|
Tester Connection |
Condition |
Specified Condition |
|---|---|---|
|
PW1-8 (FSP+) - PW1-9 (FSP-) |
Always |
1 MΩ or higher |
|
PW1-8 (FSP+) - Body ground |
||
|
PW1-9 (FSP-) - Body ground |
|
|
11. |
CHECK NO. 2 FLOOR WIRE |
(a) Connect the cable to the negative (-) battery terminal, and wait for at least 2 seconds.
(b) Turn the ignition switch to ON, and wait for at least 60 seconds.
(c) Measure the voltage according to the value(s) in the table below.
Standard Voltage:
|
Tester Connection |
Switch Condition |
Specified Condition |
|---|---|---|
|
P14-8 (FSR+) - Body ground |
Ignition switch ON |
Below 1 V |
|
P14-4 (FSR-) - Body ground |
(d) Turn the ignition switch off.
(e) Disconnect the cable from the negative (-) battery terminal, and wait for at least 90 seconds.
(f) Using a service wire, connect terminals 12 (FSP+) and 13 (FSP-) of connector B.
NOTICE:
Do not forcibly insert the service wire into the terminals of the connector.
(g) Measure the resistance according to the value(s) in the table below.
Standard Resistance:
|
Tester Connection |
Condition |
Specified Condition |
|---|---|---|
|
P14-8 (FSR+) - P14-4 (FSR-) |
Always |
Below 1 Ω |
(h) Disconnect the service wire from connector B.
(i) Measure the resistance according to the value(s) in the table below.
Standard Resistance:
|
Tester Connection |
Condition |
Specified Condition |
|---|---|---|
|
P14-8 (FSR+) - P14-4 (FSR-) |
Always |
1 MΩ or higher |
|
P14-8 (FSR+) - Body ground |
||
|
P14-4 (FSR-) - Body ground |
|
|
12. |
CHECK FOR DTC |
(a) Connect the connectors to the occupant classification ECU and the center airbag sensor.
(b) Connect the cable to the negative (-) battery terminal, and wait for at least 2 seconds.
(c) Turn the ignition switch to ON, and wait for at least 60 seconds.
(d) Clear any DTCs stored in the memory
.
HINT:
- First clear any DTCs stored in the occupant classification ECU and then in the center airbag sensor.
- Use the Techstream to clear the DTCs of the occupant classification ECU, otherwise the DTCs cannot be cleared.
(e) Turn the ignition switch off.
(f) Turn the ignition switch to ON, and wait for at least 60 seconds.
(g) Using the Techstream, check for DTCs of the occupant classification ECU
.
OK:
DTC B1790 is not output.
HINT:
DTCs other than DTC B1790 may be output at this time, but they are not related to this check.
|
|
13. |
REPLACE OCCUPANT DETECTION ECU |
(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 occupant classification ECU
.
HINT:
Perform the inspection using parts from a normal vehicle when possible.
|
|
14. |
PERFORM ZERO POINT CALIBRATION |
(a) Connect the cable to the negative (-) battery terminal, and wait for at least 2 seconds.
(b) Connect the Techstream to the DLC3.
(c) Turn the ignition switch to ON, and wait for at least 60 seconds.
(d) Using the Techstream, perform the zero point calibration
.
|
|
15. |
PERFORM SENSITIVITY CHECK |
(a) Using the Techstream, perform the sensitivity check
.
Standard range:
27 to 33 kg (59.5 to 72.8 lb)
|
|
16. |
CHECK FOR DTC |
(a) Connect the connector to the occupant classification ECU.
(b) Connect the cable to the negative (-) battery terminal, and wait for at least 2 seconds.
(c) Turn the ignition switch to ON, and wait for at least 60 seconds.
(d) Clear any DTCs stored in the memory
.
HINT:
- First clear DTCs stored in the occupant classification ECU and then in the center airbag sensor.
- Use the Techstream to clear the DTCs of the occupant classification ECU, otherwise the DTCs cannot be cleared.
(e) Turn the ignition switch off.
(f) Turn the ignition switch to ON, and wait for at least 60 seconds.
(g) Using the Techstream, check for DTCs of the occupant classification ECU
.
OK:
DTC B1790 is not output.
HINT:
DTCs other than DTC B1790 may be output at this time, but they are not related to this check.
|
|
|