Inspection Procedure O-5

The ETACS-ECU does not receive any signal from the door lock key cylinder switch.

Door Lock Key Cylinder Switch Input Circuit Part 1:

Door Lock Key Cylinder Switch Input Circuit Part 2:

CIRCUIT OPERATION
The ETACS-ECU operates the central door locking system according to signal from the door lock key cylinder switch.

TECHNICAL DESCRIPTION (COMMENT)
If the signal is not normal, the systems, which are described in "CIRCUIT OPERATION", do not work normally.

TROUBLESHOOTING HINTS
- The door lock key cylinder switch may be defective.
- The wiring harness or connectors may have loose, corroded, or damaged terminals, or terminals pushed back in the connector.
- The ETACS-ECU may be defective.

DIAGNOSIS

Required Special Tools:
- MB991223: Harness Set
- MB991502: Scan Tool (MUT-II)
- MB991496: Main unit
- MB991497: Test Harness (for communication)

- MB991958: Scan Tool (MUT-III Sub Assembly)
- MB991824: V.C.I.
- MB991827: USB Cable
- MB991911: Main Harness B

STEP 1. Check the input signal (by using the pulse check mode of the monitor).
Check the input signals from the door lock key cylinder switch.

CAUTION To prevent damage to scan tool MB991502 or MB991958, always turn the ignition switch to the "LOCK" (OFF) position before connecting or disconnecting scan tool MB991502 or MB991958.







1. Connect the special tool. Refer to "How to connect SWS monitor".
2. Operate scan tool MB991502 or 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."

3. Check that scan tool MB991502 or MB991958 sounds.

Q: When each of the driver's and passenger's door lock key cylinder switch is operated, does scan tool MB991502 or MB991958 sound?

When the door lock key cylinder switch (LH) is operated, scan tool MB991502 or MB991958 does not sound.: Go to Step 2.

When the door lock key cylinder switch (RH) is operated, scan tool MB991502 or MB991958 does not sound.: Go to Step 8.

STEP 2. Check door lock key cylinder switch (LH) connector E-01 for loose, corroded or damaged terminals, or terminals pushed back in the connector.




Q: Is door lock key cylinder switch (LH) connector E-01 in good condition?

YES: Go to Step 3.

NO: Repair or replace the damaged component(s). Refer to Harness Connector Inspection. If the systems, which are described in "CIRCUIT OPERATION", work normally, the input signal from the door lock key cylinder switch (LH) should be normal.

STEP 3. Check the door lock key cylinder switch (LH).







Disconnect door lock key cylinder switch (LH) connector E-01. Then check continuity between the switch terminals.

Q: Is the door lock key cylinder switch (LH) in good condition?

YES: Go to Step 4.

NO: Replace the door lock key cylinder switch (LH). If the systems, which are described in "CIRCUIT OPERATION", work normally, the input signal from the door lock key cylinder switch (LH) should be normal.

STEP 4. Check the ground circuit to the door lock key cylinder switch (LH). Measure the resistance at door lock key cylinder switch (LH) connector E-01.




1. Disconnect door lock key cylinder switch (LH) connector E-01 and measure the resistance available at the wiring harness side of the connector.




2. Measure the resistance value 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 6.

NO: Go to Step 5.

STEP 5. Check the wiring harness between door lock key cylinder switch (LH) connector E-01 (terminal 2) and ground.









NOTE: Also check intermediate connector C-17 for loose, corroded, or damaged terminals, or terminals pushed back in the connector. If intermediate connectors C-17 is damaged, repair or replace the damaged components) as described in Harness Connector Inspection.

Q: Is the wiring harness between door lock key cylinder switch (LH) connector E-01 (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. If the systems, which are described in "CIRCUIT OPERATION", work normally, the input signal from the door lock key cylinder switch (LH) should be normal.

STEP 6. Check ETACS-ECU connector C-227 for loose, corroded or damaged terminals, or terminals pushed back in the connector.




Q: Is ETACS-ECU connector C-227 in good condition?

YES: Go to Step 7.

NO: Repair or replace the damaged component(s). Refer to Harness Connector Inspection. If the systems, which are described in "CIRCUIT OPERATION", work normally, the input signal from the door lock key cylinder switch (LH) should be normal.

STEP 7. Check the wiring harness between door lock key cylinder switch (LH) connector E-01 (terminal 1 and 3) and ETACS-ECU connector C-227 (terminal 25 and 42).












NOTE: Also check intermediate connector C-17 for loose, corroded, or damaged terminals, or terminals pushed back in the connector. If intermediate connectors C-17 is damaged, repair or replace the damaged components) as described in Harness Connector Inspection.

Q: Is the wiring harness between door lock key cylinder switch (LH) connector E-01 (terminal 1 and 3) and ETACS-ECU connector C-227 (terminal 25 and 42) in good condition?

YES: Replace the ETACS-ECU. If the systems, which are described in "CIRCUIT OPERATION", work normally, the input signal from the door lock key cylinder switch (LH) should be normal.

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. If the systems, which are described in "CIRCUIT OPERATION", work normally, the input signal from the door lock key cylinder switch (LH) should be normal.

STEP 8. Check door lock key cylinder switch (RH) connector E-12 for loose, corroded or damaged terminals, or terminals pushed back in the connector.




Q: Is door lock key cylinder switch (RH) connector E-12 in good condition?

YES: Go to Step 9.

NO: Repair or replace the damaged component(s). Refer to Harness Connector Inspection. If the systems, which are described in "CIRCUIT OPERATION", work normally, the input signal from the door lock key cylinder switch (RH) should be normal.

STEP 9. Check the door lock key cylinder switch (RH).







Disconnect door lock key cylinder switch (RH) connector E-12. Then check continuity between the switch terminals.

Q: Is the front door lock key cylinder switch (RH) in good condition?

YES: Go to Step 10.

NO: Replace the front passenger's door lock key cylinder switch. If the systems, which are described in "CIRCUIT OPERATION", work normally, the input signal from the door lock key cylinder switch (RH) should be normal.

STEP 10. Check the ground circuit to the door lock key cylinder switch (RH). Measure the resistance at door lock key cylinder switch (RH) connector E-12.




1. Disconnect door lock key cylinder switch (RH) connector E-12 and measure the resistance available at the wiring harness side of the connector.




2. Measure the resistance value 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 12.

NO: Go to Step 11.

STEP 11. Check the wiring harness between door lock key cylinder switch (RH) connector E-12 (terminal 2) and ground.









NOTE: Also check intermediate connector C-110 for loose, corroded, or damaged terminals, or terminals pushed back in the connector. If intermediate connectors C-110 is damaged, repair or replace the damaged components) as described in Harness Connector Inspection.

Q: Is the wiring harness between door lock key cylinder switch (RH) connector E-12 (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. If the systems, which are described in "CIRCUIT OPERATION", work normally, the input signal from the door lock key cylinder switch (RH) should be normal.

STEP 12. Check ETACS-ECU connector C-227 for loose, corroded or damaged terminals, or terminals pushed back in the connector.




Q: Is ETACS-ECU connector C-227 in good condition?

YES: Go to Step 13.

NO: Repair or replace the damaged component(s). Refer to Harness Connector Inspection. If the systems, which are described in "CIRCUIT OPERATION", work normally, the input signal from the door lock key cylinder switch (RH) should be normal.

STEP 13. Check the wiring harness between door lock key cylinder switch (RH) connector E-12 (terminal 1 and 3) and ETACS-ECU connector C-227 (terminal 33 and 34).












NOTE: Also check intermediate connector C-110 for loose, corroded, or damaged terminals, or terminals pushed back in the connector. If intermediate connectors C-110 is damaged, Repair or replace the damaged components) as described in Harness Connector Inspection.

Q: Is the wiring harness between door lock key cylinder switch (RH) connector E-12 (terminal 1 and 3) and ETACS-ECU connector C-227 (terminal 33 and 34) in good condition?

YES: Replace the ETACS-ECU. If the systems, which are described in "CIRCUIT OPERATION", work normally, the input signal from the door lock key cylinder switch (RH) should be normal.

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. If the systems, which are described in "CIRCUIT OPERATION", work normally, the input signal from the door lock key cylinder switch (RH) should be normal.