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Home >> Mitsubishi >> 2006 >> Lancer Evolution L4-2.0L DOHC Turbo >> Repair and Diagnosis >> Body and Frame >> Body Control Systems >> Testing and Inspection >> Symptom Related Diagnostic Procedures >> Symptom Diagnostic Procedures >> Inspection Procedure I-1

Inspection Procedure I-1

Seat Belt Warning Light: The seat belt warning light does not work normally.

NOTE: This troubleshooting procedure requires the use of scan tool MB991958 and SWS monitor kit MB991813. For details on how to use the SWS monitor, refer to "How to use SWS monitor."

Seat Belt Warning Light Circuit Part 1:




Seat Belt Warning Light Circuit Part 2:






CIRCUIT OPERATION
- The ETACS-ECU operates the seat belt warning light according to the following switch signals:
- Ignition switch (IG1)
- Driver's seat belt switch
- If the driver turn the ignition switch to the "ON" position without fastening the seat belt, the seat belt warning light illuminates.

TECHNICAL DESCRIPTION (COMMENT)
If the seat belt warning light does not illuminate, the input circuit, the combination meter (seat belt warning light bulb or printed-circuit board) or the ETACS-ECU may be defective.

TROUBLESHOOTING HINTS
- The driver's side seat belt switch may be defective
- The combination meter (seat belt warning light bulb or printed-circuit board) 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: Harness Set
- MB992006: Extra Fine Probe
- MB991958: Scan Tool (M.U.T.-III Sub Assembly)
- MB991824: V.C.I.
- MB991827: M.U.T.-III USB Cable
- MB991911: M.U.T.-III Main Harness B
- MB991862: SWS monitor kit

STEP 1. Use scan tool MB991958 to select "ECU COMM Check" on the SWS monitor display.
Check the ETACS-ECU.

CAUTION: To prevent damage to scan tool MB991958, always turn the ignition switch to the "LOCK" (OFF) position before connecting or disconnecting scan tool MB991958. Also connect SWS monitor kit MB991862 after turning on scan tool MB991958.




1. Connect the special tool. Refer to "How to connect SWS monitor."
2. When the ignition switch is turned to the "ON" position.
3. Operate scan tool MB991958 according to the procedure below to display "ECU COMM Check."
a. Select "Interactive Diagnosis."
b. Select "System select."
c. Select "SWS."
d. Select "SWS MONITOR."
e. Select "ECU COMM Check."

4. Scan tool MB991958 should show "OK" on the "ECU COMM Check" menu for the "ETACS ECU" menu.

Q: Is "OK" displayed on the "ETACS ECU" menu?

YES: Go to Step 2.

NO: Refer to Inspection Procedure A-3 "Communication with ETACS-ECU is not possible."

STEP 2. Check the input signal by using "Data List" menu of the SWS monitor.
Turn the ignition switch to the "ON" position before checking input signals from the ignition switch (IG1).




1. Operate scan tool MB991958 according to the procedure below to display "ETACS ECU."
a. Select "Interactive Diagnosis."
b. Select "System select."
c. Select "SWS."
d. Select "SWS MONITOR."
e. Select "Data List."
f. Select "ETACS ECU."




2. Check that normal condition are displayed on the item described in the table.

Q: Is normal condition displayed "IG SW (IG1)"?

YES: Go to Step 3.

NO: Refer to Inspection Procedure N-2 "ETACS-ECU does not receive a signal from the ignition switch (IG1)."

STEP 3. Check the input signal (by using the pulse check mode of the monitor).
Check input signal from the driver's side seat belt switch.
- Driver's seat belt: fastened




1. Operate scan tool MB991958 according to the procedure below to display "Pulse check."
a. Select "Interactive Diagnosis."
b. Select "System select."
c. Select "SWS."
d. Select "Pulse Checking."

2. Check scan tool MB991958 sounds when the driver's seat belt is unfastened.

Q: Does scan tool MB991958 sound when the driver's side seat belt is fastened?

Yes: Go to Step 4.

No: Refer to Inspection Procedure O-3 "ETACS-ECU does not receive a signal from the driver's side seat belt switch."




STEP 4. Check ETACS-ECU connector C-228 for loose, corroded or damaged terminals, or terminals pushed back in the connector.

Q: Is ETACS-ECU connector C-228 in good condition?

YES: Go to Step 5.

NO: Repair or replace the damaged component(s). Refer to Harness Connector Inspection. Verify that the seat belt warning light illuminates normally.

STEP 5. Check at ETACS-ECU connector C-228 in order to check the ground circuit to the seat belt warning light.




1. Disconnect ETACS-ECU connector C-228, and measure at the wiring harness side.
2. Turn the ignition switch to the "ON" position.




3. Connect terminal No.73 to ground.

Q: Does the seat belt warning light illuminate?

YES: Replace the ETACS-ECU. Verify that the seat belt warning light illuminates normally.

NO: Go to Step 6.




STEP 6. Check the seat belt warning light bulb.

Q: Is the seat belt warning light bulb in good condition?

YES: Go to Step 7.

NO: Replace the bulb. Verify that the seat belt warning light illuminates normally.

STEP 7. Check the combination meter (printed-circuit board).




1. Remove the combination meter.
2. Remove the seat belt warning light bulb. Then measure the resistance value between the bulb terminals.
3. Install the bulb to the combination meter, and then measure the resistance value between connector C-01 (terminal 9) and connector C-02 (terminal 35). The measured resistance value should be roughly the same as the value measured in Step 2.

Q: Are these two resistance values extremely different?

YES: Repair or replace the combination meter (printed circuit board). Verify that the seat belt warning light illuminates normally.

NO: (much the same): Go to Step 8.




STEP 8. Check combination meter connector C-01 for loose, corroded or damaged terminals, or terminals pushed back in the connector.

Q: Is combination meter connector C-01 in good condition?

YES: Go to Step 9.

NO: Repair or replace the damaged components). Refer to Harness Connector Inspection. Verify that the seat belt warning light illuminates normally.

STEP 9. Check the ignition switch (IG1) circuit to the combination meter. Test at combination meter connector C-01.




1. Disconnect combination meter connector C-01 and measure the voltage available at the harness side of the connector.
2. Turn the ignition switch to the "ON" position.




3. Measure the voltage between terminal 9 and ground.
- The voltage should equal approximately 12 volts (battery positive voltage).

Q: Is the measured voltage approximately 12 volts (battery positive voltage)?

YES: Go to Step 11.

NO: Go to Step 10.










STEP 10. Check the wiring harness between combination meter connector C-01 (terminal 9) and the ignition switch (IG1).

NOTE: Also check junction block connectors C-211, C-214 and joint connector C-23 for loose, corroded, or damaged terminals, or terminals pushed back in the connector. If junction block connector C-211, C-214 or joint connectors C-23 is damaged, repair or replace the damaged components) as described in Harness Connector Inspection.

Q: Is the wiring harness between combination meter connector C-01 (terminal 9) and the ignition switch (IG1) 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. Verify that the seat belt warning light illuminates normally.







STEP 11. Check combination meter connector C-02 for loose, corroded or damaged terminals, or terminals pushed back in the connector.

Q: Is ETACS-ECU connector C-228 in good condition?

YES: Go to Step 12.

NO: Repair or replace the damaged components). Refer to Harness Connector Inspection. Verify that the seat belt warning light illuminates normally.







STEP 12. Check the wiring harness between combination meter connector C-02 (terminal 35) and ETACS-ECU connector C-228 (terminal 73).

Q: Is the wiring harness between combination meter connector C-02 (terminal 35) and ETACS-ECU connector C-228 (terminal 73) 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. Verify that the seat belt warning light.
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