Inspection Procedure O-7

The driver's seat belt switch Is not sent to the ETACS-ECU.

Driver's Seat Belt Switch Input Circuit:

CIRCUIT OPERATION
The ETACS-ECU operates various functions according to the input signals from the driver's seat belt switch.

TECHNICAL DESCRIPTION (COMMENT)
The driver's seat belt switch input signal is used to operate the following functions; seat belt tone alarm function, seat belt warning light. If the input signal is an error, these functions will not work normally.

TROUBLESHOOTING HINTS
- Malfunction of the driver's inner seat belt (driver's seat belt switch)
- Malfunction of the ETACS-ECU
- Damaged harness wires or connectors

DIAGNOSIS

Required Special Tools:
- MB991223: Test Harness Set
- MB991502: Scan Tool (MUT-II)
- MB991529: Diagnostic Trouble Code Check Harness







STEP 1. Check the driver's seat belt switch.

Q: Is the driver's seat belt switch in good condition?

YES: Go to Step 2.
NO: Replace the driver's inner seat belt. The driver's seat belt switch input signal should be able to be checked and the functions, which are described in the "Technical Description (comment)," should work normally.

STEP 2. Check the driver's seat belt switch ground circuit at driver's seat belt switch connector D-15.
1. Disconnect driver's seat belt switch connector D-15 and measure at the harness side.




2. Measure the resistance between terminal 1 and ground.

Q: Is the resistance less than 2 ohm?

YES: Go to Step 5.
NO: Go to Step 3.




STEP 3. Check driver's seat belt switch connector D-15 for damage.

Q: Is driver's seat belt switch connector D-15 in good condition?

YES: Go to Step 4.
NO: Repair or replace it. Refer to Harness Connector Inspection. The driver's seat belt switch input signal should be able to be checked and the functions, which are described in the "Technical Description (comment)," should work normally.




STEP 4. Check the harness wire between driver's seat belt switch connector D-15 and ground.

Q: Is the harness wire between driver's seat belt switch connector D-15 and ground in good condition?

YES: There is no action to be taken.
NO: Repair it. The driver's seat belt switch input signal should be able to be checked and the functions, which are described in the "Technical Description (comment)," should work normally.







STEP 5. Check driver's seat belt switch connector D-15 and ETACS-ECU connector C-313 for damage.

Q: Are driver's seat belt switch connector D-15 and ETACS-ECU connector C-313 in good condition?

YES: Go to Step 6.
NO: Repair or replace them. Refer to Harness Connector Inspection. The driver's seat belt switch input signal should be able to be checked and the functions, which are described in the "Technical Description (comment)," should work normally.







STEP 6. Check the harness wires between driver's seat belt switch connector D-15 and ETACS-ECU connector C-313.






NOTE: After checking intermediate connector C-210, check the wires. If intermediate connector C-210 is damaged, repair or replace it. Refer to Harness Connector Inspection.

Q: Are the harness wires between driver's seat belt switch connector D-15 and ETACS-ECU connector C-313 in good condition?

YES: Replace the ETACS-ECU. The driver's seat belt switch input signal should be able to be checked and the functions, which are described in the "Technical Description (comment)," should work normally.
NO: Repair them. The driver's seat belt switch input signal should be able to be checked and the functions, which are described in the "Technical Description (comment)," should work normally.