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Inspection Procedure 6

Forgotten Key Prevention Function does not Operate (Center Door Locking System Function Works Normally)









TECHNICAL DESCRIPTION (COMMENT)
The ETACS-ECU operates the forgotten key prevention function, based on the input signals from the following switches:
- Key reminder switch
- Driver's or front passenger's door switch. If the function does not work normally, a defect on the relevant circuit or the ETACS-ECU may be suspected.

TROUBLESHOOTING HINTS
- Malfunction of the key reminder switch
- Malfunction of the driver's or front passenger's door 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. Choose method of ETACS-ECU input signal check.

Q: Is the ETACS-ECU input signal check performed by scan tool MB991502 or a voltmeter?
By Scan tool MB991502 : Go to Step 2.
By a Voltmeter [Key reminder switch input signal check] : Go to Step 3.
By a Voltmeter [Driver's door switch input signal check] : Go to Step 4.
By a Voltmeter [Front passenger's door switch input signal check] : Go to Step 5.







STEP 2. Check the input signal (by using pulse check).
Check the ETACS-ECU input signal (key reminder switch and front door switch) by using scan tool MB99152.
Check the input signals from the following switches:
- Key reminder switch
- Driver's and front passenger's door switch

CAUTION: To prevent damage to scan tool MB991502, always turn the ignition switch to the "LOCK" (OFF) position before connecting or disconnecting scan tool MB991502.

1. Connect scan tool MB991502 to the data link connector (16-pin).
2. Check that the tone alarm of scan tool MB991502 sounds when the input signal enters.

Q: Does the tone alarm of scan tool MB991502 sound when the input signal enters?
YES: Replace the ETACS-ECU and then go to Step 17.
NO [Key reminder switch input signal] : Go to Step 6.
NO [Driver's door switch input signal] : Go to Step 7.
NO [Front passenger's door switch input signal] : Go to Step 8.







STEP 3. Check the ETACS-ECU input signal from the key reminder switch (by using a voltmeter).
1. Use special tool MB991529 to connect a voltmeter between ground terminal 4 or 5 and ETACS-ECU terminal 9 of the data link connector.
2. Check that the voltmeter indicator deflects once when the key reminder switch is operated [key in (off)/key out (on)].

Q: Does the voltmeter indicator deflect?
YES: Replace the ETACS-ECU and then go to Step 17.
NO: Go to Step 6.







STEP 4. Check the input signal from the driver's door switch (by using a voltmeter).
1. Use special tool MB991529 to connect a voltmeter between ground terminal 4 or 5 and ETACS-ECU terminal 9 of the data link connector.
2. Check that the voltmeter indicator deflects once when the Driver's door switch is operated [open (on)/depressed (off)].

Q: Does the voltmeter indicator deflect?
YES: Replace the ETACS-ECU and then go to Step 17.
NO: Go to Step 7.







STEP 5. Check the input signal from the front passenger's door switch (by using a voltmeter).
1. Use special tool MB991529 to connect a voltmeter between ground terminal 4 or 5 and ETACS-ECU terminal 9 of the data link connector.
2. Check that the voltmeter indicator deflects once when the front passenger's door switch is operated [open (on)/depressed (off)].

Q: Does the voltmeter indicator deflect?
YES: Replace the ETACS-ECU and then go to Step 17.
NO: Go to Step 8.







STEP 6. Check the key reminder switch.
1. Remove the driver's side under cover.
2. Remove the column cover, lower and upper.
3. Disconnect the key reminder switch connector and measure at the key reminder switch side.
4. Measure the resistance between terminal numbers 4 and 6.







5. Follow the table to check the key reminder switch continuity.

Q: Is the key reminder switch damaged?
YES: Replace the key reminder switch, then go to Step 18.
NO: Go to Step 7.







STEP 7. Check for continuity between key reminder switch connector D-16 terminal 4 and each of the other terminals as well as terminal 6 and each of the other terminals.

1. Disconnect key reminder switch connector D-16 and measure the resistance available at the equipment side of the connector.
2. Check for continuity between key reminder switch connector D-16 terminal 4 and each of the other terminals as well as terminal 6 and each of the other terminals.

Q: Does the continuity exist between the terminals?
NO: Go to Step 8.
YES: Replace the key reminder switch (Refer to Ignition switch). Then go to Step 18.

STEP 8. Check the driver's door switch







1. Remove the driver's side door switch.







2. Follow the table to check the driver's door switch continuity.

Q: Is the driver's side door switch in good condition?
YES: Go to Step 14.
NO: Replace the front driver's side door switch, then go to Step 18.

STEP 9. Check the front passenger's door switch







1. Remove the front passenger's door switch.







2. Follow the table to check the passenger's door switch continuity.

Q: Is the front passenger's door switch in good condition?
YES: Go to Step 16.
NO: Replace the front passenger's door switch, then go to Step 18.










STEP 10. Check ETACS-ECU connector D-11 and key reminder switch connector D-16 for loose, corroded or damaged terminals, or terminals pushed back in the connector.

Q: Are the connectors in good condition?
YES: Go to Step 11.
NO: Repair or replace the damaged components. Refer to Harness Connector inspection.Then go to Step 18.
















STEP 11. Check the harness wire between ETACS-ECU connector D-11 (terminal No.8) and key reminder switch connectors D-16 (terminal No.6).

NOTE: After inspecting intermediate connector C-72, junction block connector D-13 inspect the wires. If intermediate connector C-72, junction block connector D-13 is damaged, repair or replace it. Refer to Harness Connector Inspection. Then go to Step 17.

Q: Are there any damaged harness wires?
YES: Repair or replace the harness wire, then go to Step 18.
NO: Go to Step 12.







STEP 12. Check key reminder switch connector D-16.

Q: Is key reminder switch connector D-16 in good condition?
YES: Go to Step 12.
NO: Repair or replace the damaged components. Refer to Harness Connector inspection. Then go to Step 18.







STEP 13. Check the harness wire between key reminder switch connector D-16 and ground.

Q: Is the harness wire between key reminder switch connector D-16 and ground damaged?
YES: Repair or replace the harness wire, then go to Step 18.
NO: Go to Step 14.










STEP 14. Check ETACS-ECU connectors D-11, D-27 and driver's door switch connector E-33 for loose, corroded or damaged terminals, or terminals pushed back in the connector.

Q: Are the connectors in good condition?
YES: Go to Step 15.
NO: Repair or replace the damaged components. Repair or replace them. Refer to Harness Connector inspection. Then go to Step 18.
















STEP 15. Check the harness wires between ETACS-ECU connectors D-11 (terminal No.9), D-27 (terminal No.51) and driver's door switch connector E-33 (terminal No.1 and 2).

NOTE: After inspecting junction block connector D-14, intermediate connectors E-41 and E-42 inspect the wire. If junction block connector D-14, intermediate connectors E-41 or E-42 is damaged, repair or replace it. Refer to Harness Connector Inspection. Then go to Step 17.

Q: Are there any damaged harness wires between ETACS-ECU connectors D-11 (terminal No.9), D-27 (terminal No.51) and driver's door switch connector E-33 (terminal No.1 and 2)?
YES: Repair or replace the harness wire, then go to Step 18.
NO: Go to Step 16.










STEP 16. Check ETACS-ECU connectors D-26, D-27 and front passenger's door switch connector E-46 for loose, corroded or damaged terminals, or terminals pushed back in the connector.

Q: Are the connectors in good condition?
YES: Go to Step 17.
NO: Repair or replace the damaged components. Refer to Harness Connector inspection. Then go to Step 18.













STEP 17. Check the harness wires between ETACS-ECU connector D-26 (terminal No.23), D-27 (terminal No.51) and front passenger's door switch connector E-46 (terminal No.1 and 2).

NOTE: After inspecting intermediate connectors E-41 and E-42 inspect the wire. If intermediate connectors E-41 or E-42 is damaged, repair or replace it. Refer to Harness Connector Inspection. Then go to Step 17.

Q: Are there any damaged harness wires between ETACS-ECU connectors D-26 (terminal No.23), D-27 (terminal No.51) and front passenger's door switch connector E-46 (terminal No.1 and 2)?
YES: Repair or replace the harness wire, then go to Step 18.
NO: Go to Step 17.

STEP 18. Retest the system.

Q: Does the door lock function operate normally?
YES: The procedure is complete.
NO: Return to Step 1.
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