Toyota Tacoma (2015-2018) Service Manual: Front Occupant Classification Sensor RH Collision Detection (B1786)
DESCRIPTION
DTC B1786 is set when the occupant detection ECU receives a collision detection signal, which is sent by the front occupant classification sensor RH when an accident occurs.
DTC B1786 is also set when the front seat with adjuster frame 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 is not in a collision, DTC B1786 can be cleared by conducting the zero point calibration and sensitivity check.
Therefore, if DTC B1786 is set, first perform the zero point calibration and sensitivity check.
|
DTC No. |
DTC Detecting Conditions |
Trouble Areas |
|---|---|---|
|
B1786 |
|
|
HINT:
- When DTC B1650/32 is set as a result of troubleshooting the supplemental restraint system, perform troubleshooting for DTC B1786 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
(See page .gif)
)
PROCEDURE
|
1. |
CHECK DTC |
(a) Turn the ignition switch to the ON position.
(b) Clear any DTCs stored in the airbag sensor assembly (See page
).
(c) Turn the ignition switch to the LOCK position.
(d) Turn the ignition switch to the ON position.
(e) Using the Techstream, check for DTCs of the occupant detection ECU (See page
).
OK:
DTC B1786 is not output.
HINT:
DTCs other than B1786 may be output at this time, but they are not related to this check.
| OK | .gif) |
USE SIMULATION METHOD TO CHECK |
|
.gif)
|
2. |
PERFORM ZERO POINT CALIBRATION |
(a) Connect the Techstream to the DLC3.
(b) Turn the ignition switch to the ON position.
(c) Using the Techstream, perform the zero point calibration (See page
).
OK:
"Zero Point Calibration is complete." is displayed on the Techstream.
| NG | |
GO TO STEP 5 |
|
|
3. |
PERFORM SENSITIVITY CHECK |
(a) Using the Techstream, perform the sensitivity check (See page
).
Standard:
27 to 33 kg (59.52 to 72.75 lb)
| NG | |
GO TO STEP 5 |
|
|
4. |
CHECK DTC |
(a) Turn the ignition switch to the ON position.
(b) Clear any DTCs stored in the airbag sensor assembly (See page
).
(c) Turn the ignition switch to the LOCK position.
(d) Turn the ignition switch to the ON position.
(e) Using the Techstream, check for DTCs of the occupant detection ECU (See page
).
OK:
DTC B1786 is not output.
HINT:
DTCs other than B1786 may be output at this time, but they are not related to this check.
| NG | |
USE SIMULATION METHOD TO CHECK |
|
|
5. |
REPLACE FRONT SEAT WITH ADJUSTER FRAME ASSEMBLY RH |
(a) Turn the ignition switch to the LOCK position.
(b) Disconnect the negative (-) terminal cable from the battery, and wait for at least 90 seconds.
(c) Replace the front seat with adjuster frame assembly RH (See page
).
HINT:
Perform the inspection using parts from a normal vehicle when possible.
|
|
6. |
PERFORM ZERO POINT CALIBRATION |
(a) Connect the negative (-) terminal cable to the battery.
(b) Connect the Techstream to the DLC3.
(c) Turn the ignition switch to the ON position.
(d) Using the Techstream, perform the zero point calibration (See page
).
OK:
"Zero Point Calibration is complete." is displayed on the Techstream.
| NG | |
GO TO STEP 9 |
|
|
7. |
PERFORM SENSITIVITY CHECK |
(a) Using the Techstream, perform the sensitivity check (See page
).
Standard:
27 to 33 kg (59.52 to 72.75 lb)
| NG | |
GO TO STEP 9 |
|
|
8. |
CHECK DTC |
(a) Connect the connectors to the occupant detection ECU and the front occupant classification sensor RH.
(b) Connect the negative (-) terminal cable to the battery.
(c) Turn the ignition switch to the ON position.
(d) Clear any DTCs stored in the memory (See page
).
HINT:
- First clear DTCs stored in the occupant detection ECU and then in the airbag sensor assembly.
- Use the Techstream to clear the DTCs of the occupant detection ECU, otherwise the DTCs cannot be cleared.
(e) Turn the ignition switch to the LOCK position.
(f) Turn the ignition switch to the ON position.
(g) Using the Techstream, check for DTCs of the occupant detection ECU (See page
).
OK:
DTC B1786 is not output.
HINT:
DTCs other than B1786 may be output at this time, but they are not related to this check.
| OK | |
USE SIMULATION METHOD TO CHECK |
|
|
9. |
REPLACE OCCUPANT DETECTION ECU |
(a) Turn the ignition switch to the LOCK position.
(b) Disconnect the negative (-) terminal cable from the battery, and wait for at least 90 seconds.
(c) Replace the occupant detection ECU (See page
).
|
|
10. |
PERFORM ZERO POINT CALIBRATION |
(a) Connect the negative (-) terminal cable to the battery.
(b) Connect the Techstream to the DLC3.
(c) Turn the ignition switch to the ON position.
(d) Using the Techstream, perform the zero point calibration (See page
).
OK:
"Zero Point Calibration is complete." is displayed on the Techstream.
|
|
11. |
PERFORM SENSITIVITY CHECK |
(a) Using the Techstream, perform the sensitivity check (See page
).
Standard :
27 to 33 kg (59.52 to 72.75 lb)
| NEXT | |
USE SIMULATION METHOD TO CHECK |
Front Occupant Classification Sensor LH Collision Detection (B1785)
DESCRIPTION
DTC B1785 is set when the occupant detection ECU receives a collision detection
signal, which is sent by the occupant classification sensor front LH when an accident
occurs.
DTC B178 ...
Passenger Side Buckle Switch Circuit Malfunction (B1771)
DESCRIPTION
The passenger side buckle switch circuit consists of the occupant detection ECU
and the front seat inner belt assembly RH.
DTC B1771 is recorded when a malfunction is detected in the p ...
Other materials:
Disassembly
DISASSEMBLY
PROCEDURE
1. REMOVE PRESSURE RELIEF VALVE
(a) Remove the pressure relief valve and O-ring.
2. REMOVE MAGNET CLUTCH ASSEMBLY
(a) Secure the cooler compressor assembly in a vise between aluminum plates.
(b) Using SST, hold the magnet clutch hub.
SST: 09985-00260
(c) Remove the ...
Neutral Position Switch Circuit
DESCRIPTION
The ECM uses the neutral position switch installed to the manual transmission
assembly to detect when the transmission is in the neutral position.
WIRING DIAGRAM
PROCEDURE
1.
READ VALUE USING TECHSTREAM (NEUTRAL SWITCH)
(a) Connect the Techstream ...
Automatic High Beam System (B124B)
DESCRIPTION
The main body ECU (multiplex network body ECU) determines the status of the automatic
high beam system based on the automatic high beam system signal from the forward
recognition camera.
DTC No.
Detection Item
DTC Detection Condition
Trou ...
