Toyota Tacoma (2015-2018) Service Manual: Front Occupant Classification Sensor LH Collision Detection (B1785)

Toyota Tacoma (2015-2018) Service Manual / Supplemental Restraint Systems / Occupant Classification System / 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 B1785 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 B1785 can be cleared by conducting the zero point calibration and sensitivity check.

Therefore, if DTC B1785 is set, first perform the zero point calibration and sensitivity check.

DTC No.	DTC Detecting Conditions	Trouble Areas
B1785	Front seat with adjuster frame assembly RH malfunction Occupant detection ECU malfunction Front occupant classification sensor LH senses a large load	Front seat with adjuster frame assembly RH (Front occupant classification sensor LH) Occupant detection ECU

HINT:

When DTC B1650/32 is set as a result of troubleshooting the supplemental restraint 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

(See page PROCEDURE )

PROCEDURE

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: ).

OK:

DTC B1785 is not output.

HINT:

DTCs other than B1785 may be output at this time, but they are not related to this check.

USE SIMULATION METHOD TO CHECK

2.	PERFORM ZERO POINT CALIBRATION

(a) Connect the Techstream to the DLC3.

(b) Turn the ignition switch to the ON position.

OK:

"Zero Point Calibration is complete." is displayed on the Techstream.

GO TO STEP 5

3.	PERFORM SENSITIVITY CHECK

(a) Using the Techstream, perform the sensitivity check (See page Standard value: ).

Standard value:

27 to 33 kg (59.52 to 72.75 lb)

GO TO STEP 5

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: ).

OK:

DTC B1785 is not output.

HINT:

DTCs other than B1785 may be output at this time, but they are not related to this check.

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.

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.

(d) Using the Techstream, perform the zero point calibration (See page OK: ).

OK:

"Zero Point Calibration is complete." is displayed on the Techstream.

GO TO STEP 9

7.	PERFORM SENSITIVITY CHECK

(a) Using the Techstream, perform the sensitivity check (See page Standard : ).

Standard :

27 to 33 kg (59.52 to 72.75 lb)

GO TO STEP 9

CHECK DTC

(a) Connect the connectors to the occupant detection ECU and the front occupant classification sensor LH.

(b) Connect the negative (-) terminal cable to the battery.

(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: ).

OK:

DTC B1785 is not output.

HINT:

DTCs other than B1785 may be output at this time, but they are not related to this check.

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.

10.	PERFORM ZERO POINT CALIBRATION

(a) Connect the negative (-) terminal cable to the battery.

(b) Connect the Techstream to the DLC3.

(d) Using the Techstream, perform the zero point calibration (See page OK: ).

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: ).

Standard:

27 to 33 kg (59.52 to 72.75 lb)

USE SIMULATION METHOD TO CHECK

Rear Occupant Classification Sensor RH Circuit Malfunction (B1783)

DESCRIPTION The rear occupant classification sensor RH circuit consists of the occupant detection ECU and the rear occupant classification sensor RH. DTC B1783 is set when a malfunction is detecte ...

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 B178 ...

Other materials:

Removal
REMOVAL CAUTION / NOTICE / HINT HINT: Use the same procedure for both the LH and RH sides. The procedure described below is for the LH side. PROCEDURE 1. REMOVE NO. 1 FRONT WHEEL OPENING EXTENSION PAD (w/ Front Spoiler) 2. SEPARATE FRONT FENDER LINER (a) Remov ...

Precaution
PRECAUTION 1. DOOR CONTROL RECEIVER EXPRESSIONS (a) The type of door control receiver used on this model differs according to the specifications of the vehicle. The expressions listed in the table below are used in this section. Vehicle Specification Part Name in Manual ...

Speaker Circuit
DESCRIPTION If there is a short in a speaker circuit, the radio and display receiver assembly detects it and stops output to the speakers. Thus sound cannot be heard from the speakers even if there is no malfunction in the radio and display receiver assembly or speakers. If a ...