Lexus NX: Front Occupant Classification Sensor LH Collision Detection (B1785)
DESCRIPTION
DTC B1785 is stored when the occupant detection ECU receives a collision detection signal, which is sent by the front occupant classification sensor LH when an accident occurs.
DTC B1785 is also stored when the front seat adjuster assembly RH is subjected to a strong impact, even if an actual accident has not occurred.
However, when the occupant detection ECU outputs a collision detection signal, even if the vehicle has not been in a collision, DTC B1785 can be cleared by conducting the zero point calibration and sensitivity check.
Therefore, if DTC B1785 is output, first perform the zero point calibration and sensitivity check.
| DTC No. | Detection Item | DTC Detection Condition | Trouble Area |
|---|---|---|---|
| B1785 | Front Occupant Classification Sensor LH Collision Detection | Either condition is met:
|
|
HINT:
- When DTC B1650/32 is stored as a result of troubleshooting the airbag system, perform troubleshooting for DTC B1785 of the occupant classification system.
- Use the Techstream to check for DTCs of the occupant detection ECU, otherwise the DTCs cannot be read.
WIRING DIAGRAM
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CAUTION / NOTICE / HINT
NOTICE:
When disconnecting the cable, some systems need to be initialized after the cable is reconnected.
Click here .gif)
PROCEDURE
| 1. | CHECK DTC |
(a) Turn the power switch on (IG), and wait for at least 60 seconds.
(b) Clear the DTCs.
Click here
HINT:
- First clear the DTCs stored in the occupant detection ECU, and then clear the DTCs stored in the airbag ECU assembly.
- Use the Techstream to clear the DTCs of the occupant detection ECU, otherwise the DTCs cannot be cleared.
(c) Turn the power switch off.
(d) Turn the power switch on (IG), and wait for at least 60 seconds.
(e) Check for DTCs.
Click here
HINT:
DTCs other than DTC B1785 may be output at this time, but they are not related to this check.
| DTC B1785 is not output | .gif) | USE SIMULATION METHOD TO CHECK |
|
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| 2. | PERFORM ZERO POINT CALIBRATION |
(a) Perform the zero point calibration.
Click here
| "Zero Point Calibration is complete." is not displayed | | GO TO STEP 5 |
|
| 3. | PERFORM SENSITIVITY CHECK |
(a) Perform the sensitivity check.
Click here
Standard:
27 to 33 kg (59.5 to 72.8 lb)
| NG | | GO TO STEP 5 |
|
| 4. | CHECK DTC |
(a) Clear the DTCs.
Click here
HINT:
- First clear the DTCs stored in the occupant detection ECU, and then clear the DTCs stored in the airbag ECU assembly.
- Use the Techstream to clear the DTCs of the occupant detection ECU, otherwise the DTCs cannot be cleared.
(b) Turn the power switch off.
(c) Turn the power switch on (IG), and wait for at least 60 seconds.
(d) Check for DTCs.
Click here
HINT:
DTCs other than DTC B1785 may be output at this time, but they are not related to this check.
| DTC B1785 is not output | | END |
| DTC B1785 is output | | GO TO STEP 5 |
| 5. | REPLACE FRONT SEAT ADJUSTER ASSEMBLY RH (FRONT OCCUPANT CLASSIFICATION SENSOR LH) |
(a) Turn the power switch off.
(b) Disconnect the cable from the negative (-) auxiliary battery terminal, and wait for at least 90 seconds.
(c) Replace the front seat adjuster assembly RH.
Click here
HINT:
Perform the inspection using parts from a normal vehicle when possible.
|
| 6. | PERFORM ZERO POINT CALIBRATION |
(a) Connect the cable to the negative (-) auxiliary battery terminal, and wait for at least 2 seconds.
(b) Turn the power switch on (IG).
(c) Perform the zero point calibration.
Click here
| "Zero Point Calibration is complete." is not displayed | | GO TO STEP 9 |
|
| 7. | PERFORM SENSITIVITY CHECK |
(a) Perform the sensitivity check.
Click here
Standard:
27 to 33 kg (59.5 to 72.8 lb)
| NG | | GO TO STEP 9 |
|
| 8. | CHECK DTC |
(a) Clear the DTCs.
Click here
HINT:
- First clear the DTCs stored in the occupant detection ECU, and then clear the DTCs stored in the airbag ECU assembly.
- Use the Techstream to clear the DTCs of the occupant detection ECU, otherwise the DTCs cannot be cleared.
(b) Turn the power switch off.
(c) Turn the power switch on (IG), and wait for at least 60 seconds.
(d) Check for DTCs.
Click here
HINT:
DTCs other than DTC B1785 may be output at this time, but they are not related to this check.
| DTC B1785 is not output | | END (FRONT SEAT ADJUSTER ASSEMBLY RH [FRONT OCCUPANT CLASSIFICATION SENSOR LH] WAS DEFECTIVE) |
| DTC B1785 is output | | GO TO STEP 9 |
| 9. | REPLACE OCCUPANT DETECTION ECU |
(a) Turn the power switch off.
(b) Disconnect the cable from the negative (-) auxiliary battery terminal, and wait for at least 90 seconds.
(c) Replace the occupant detection ECU.
Click here
HINT:
Perform the inspection using parts from a normal vehicle when possible.
|
| 10. | PERFORM ZERO POINT CALIBRATION |
(a) Connect the cable to the negative (-) auxiliary battery terminal, and wait for at least 2 seconds.
(b) Turn the power switch on (IG).
(c) Perform the zero point calibration.
Click here
|
| 11. | PERFORM SENSITIVITY CHECK |
(a) Perform the sensitivity check.
Click here
Standard:
27 to 33 kg (59.5 to 72.8 lb)
| NEXT | | END (OCCUPANT DETECTION ECU WAS DEFECTIVE) |
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