Inspection Procedure 10: The seat belt switch signal is not received.

caution

Whenever the ECU is replaced, ensure that the input signal circuit is normal.

COMMENTS ON TROUBLE SYMPTOM

Input signal from the front seat belt switch is used to operate the seat belt reminder function. If the signal is abnormal, the seat belt reminder function will not work normally.

PROBABLE CAUSES

Malfunction of the front seat belt switch (LH)
Malfunction of the front seat belt switch (RH)
Malfunction of the seat belt reminder (seat occupancy sensor)
Malfunction of the ETACS-ECU
Damaged harness wires and connectors

DIAGNOSIS PROCEDURE

STEP 1. Connector check: C-25 front seat belt switch (LH) connector or C-28 front seat belt switch (RH) connector

Q. Is the check result normal?

Go to Step 2

Repair the defective connector.

STEP 2. Check the seat belt switch and seat belt reminder (seat occupancy sensor).

Refer to GROUP 52A - Front Seat Belt

Q. Is the check result normal?

Go to Step 3

Replace the seat belt switch or seat belt reminder (seat occupancy sensor).

STEP 3. Resistance measurement at the C-25 front seat belt switch (LH) connector or C-28 front seat belt switch (RH) connector.

(1)Disconnect the connector, and measure at the wiring harness side.

(2)Check the resistance between the seat belt switch connector and body earth.

Resistance between C-25 seat belt switch (LH) connector terminal No.1 and body earth
Resistance between C-28 seat belt switch (RH) connector terminal No.1 and body earth

OK: Continuity exists (2 Ω or less)

Q. Is the check result normal?

Go to Step 5

Go to Step 4

STEP 4. Check the wiring harness between each front seat belt switch connector and the body earth.

Check the earth wires for open circuit.

Check the wiring harness between C-25 front seat belt switch (LH) connector terminal No. 1 and the body earth. <front seat belt switch (LH)>
Check the wiring harness between C-28 front seat belt switch (RH) connector terminal No. 1 and the body earth. <front seat belt switch (RH)>

note

Prior to the wiring harness inspection, check joint connectors B-02, B-04, earth connectors B-11 and B-25, and repair if necessary.<LHD>

note

Prior to the wiring harness inspection, check joint connector B-02 and earth connector B-11, and repair if necessary. <RHD>

Q. Is the check result normal?

The trouble can be an intermittent malfunction (Refer to GROUP 00 - How to use Troubleshooting/inspection Service Points - How to Cope with Intermittent Malfunction

Repair the wiring harness.

STEP 5. Connector check: C-317 ETACS-ECU connector

Q. Is the check result normal?

Go to Step 6

Repair the defective connector.

STEP 6. Check the wiring harness between each front seat belt switch connector and the ETACS-ECU connector.

Check the input line for open circuit or short circuit.

Check the wiring harness between C-25 front seat belt switch (LH) connector terminal No. 1 and the C-317 ETACS-ECU connector terminal No. 66 <LHD> or 60 <RHD>. <front seat belt switch (LH)>
Check the wiring harness between C-28 front seat belt switch (RH) connector terminal No. 1 and the C-317 ETACS-ECU connector terminal No. 60 <LHD> or 66 <RHD>. <front seat belt switch (RH)>

Q. Is the check result normal?

Go to Step 7

Repair the wiring harness.

STEP 7. M.U.T.-III data list

Check the input signals from the front seat belt switch.

Remove the each inserted front seatbelt.

Item No.	Item name	Normal condition
50	Driver’s seatbelt(Buckle SW)	Being turned ON from OFF
51	Passenger seatbelt(Buckle SW)	Being turned ON from OFF

OK: Normal condition is displayed.

Q. Is the check result normal?

The trouble can be an intermittent malfunction (Refer to GROUP 00 - How to use Troubleshooting/Inspection Service Points - How to Cope with Intermittent Malfunction

Replace the ETACS-ECU and register the ID codes (Refer to

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