Inspection Procedure O-7

INSPECTION PROCEDURE O-7: The driver's seat belt switch is not sent to the ETACS-ECU.






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
- The driver's inner seat belt (driver's seat belt switch) may be defective
- The ETACS-ECU may be defective
- The wiring harness or connectors may have loose, corroded, or damaged terminals, or terminals pushed back in the connector

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 ground circuit to the driver's seat belt switch. Test at driver's seat belt switch connector D-15.




1. Disconnect driver's seat belt switch connector D-15 and measure the resistance available at the wiring harness side of the connector.




2. Measure the resistance between terminal 2 and ground.
- The resistance should equal 2 ohms or less.

Q: Is the measured resistance 2 ohms or less?

YES : Go to Step 5.

NO : Go to Step 3.




STEP 3. Check the driver's seat belt switch connector D-15 for loose, corroded or damaged terminals, or terminals pushed back in the connector.

Q: Is driver's seat belt switch connector D-15 in good condition?
YES : Go to Step 4.

NO : Repair or replace the damaged component(s). 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 wiring harness between driver's seat belt switch connector D-15 (terminal 2) and ground.

Q: Is the wiring harness between driver's seat belt switch connector D-15 (terminal 2) and ground in good condition?

YES : No action is necessary and testing is complete.

NO : The wiring harness may be damaged or the connector(s) may have loose, corroded or damaged terminals, or terminals pushed back in the connector. Repair the wiring harness as necessary. 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 the driver's seat belt switch connector D-15 and ETACS-ECU connector C-317 for loose, corroded or damaged terminals, or terminals pushed back in the connector.

Q: Are driver's seat belt switch connector D-15 and ETACS-ECU connector C-317 in good condition?

YES : Go to Step 6.

NO : Repair or replace the damaged component(s). 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 wiring harness between driver's seat belt switch connector D-15 (terminal 1) and ETACS-ECU connector C-317 (terminal 21).

NOTE: Also check intermediate connector C-210 for loose, corroded, or damaged terminals, or terminals pushed back in the connector. If intermediate connector C-210 is damaged, repair or replace the damaged components) as described in Harness Connector Inspection.

Q: Are the wiring harness between driver's seat belt switch connector D-15 (terminal 1) and ETACS-ECU connector C-317 (terminal 21) 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 : The wiring harness may be damaged or the connector(s) may have loose, corroded or damaged terminals, or terminals pushed back in the connector. Repair the wiring harness as necessary. 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.