Inspection Procedure 5

Inspection Procedure 5: Keyless entry system does not work.

CAUTION: Before replacing the ECU, ensure that the power supply circuit, the ground circuit and the communication circuit are normal.

TECHNICAL DESCRIPTION (COMMENT)

The lock/unlock signals from the transmitter are received by WCM, and then sent to ETACS-ECU from WCM. When ETACS-ECU receives signals from the key reminder switch and all the door switches, ETACS-ECU actuates the keyless entry system.

TROUBLESHOOTING HINTS

- The key reminder switch may be defective
- The door switches may be defective
- The keyless entry transmitter may be defective
- The WCM 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
- Option coding information

DIAGNOSIS

Required Special Tools:
- MB992006: Extra fine probe
- MB991223: Harness set
- MB991958 Scan Tool (M.U.T.-III Sub Assembly)
- MB991824: Vehicles Communication Interface (V.C.I.)
- MB991827 M.U.T.-III USB Cable
- MB991910 M.U.T.-III Main Harness A

STEP 1. Using scan tool MB991958, check for CAN bus the diagnostic trouble code.

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.







1. Connect scan tool MB991958. Refer to "How to connect scan tool (M.U.T.-III)". How To Connect The Scan Tool (M.U.T.-III)
2. Turn the ignition switch to the "ON" position.
3. Check whether the CAN bus lines related DTC is set.
4. Turn the ignition switch to the "LOCK" (OFF) position.

Q: Is the DTC set?

YES: Repair the CAN bus line.

NO: Go to Step 2.

STEP 2. Using scan tool MB991958, read the diagnostic trouble code.

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.







1. Connect scan tool MB991958. Refer to "How to connect scan tool (M.U.T.-III)". How To Connect The Scan Tool (M.U.T.-III)
2. Turn the ignition switch to the "ON" position.
3. Check whether the ETACS-ECU related DTC is set.
4. Turn the ignition switch to the "LOCK" (OFF) position.

Q: Is the DTC set?

YES: Diagnose the ETACS-ECU. Diagnostic Trouble Code Descriptions

NO: Go to Step 3.

STEP 3. Check the power supply system
With the ignition switch in the LOCK (OFF) position, check if the following function operates normally:
- Hazard warning light

Q: Is the check result normal?

YES: Go to Step 4.

NO: Refer to Malfunction of ETACS-ECU power supply circuit. Malfunction of ETACS-ECU power supply circuit

STEP 4. Verify the central door locking system.
Check that the central door locking system works normally.

Q: Is the check result normal?

YES: Go to Step 5.

NO: Refer to Troubleshooting. Symptom Chart

STEP 5. Using scan tool MB991958, check data list.
Check the signals related to the keyless entry system operation.

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.







1. Connect scan tool MB991958. Refer to "How to connect the Scan Tool (M.U.T.-III)". How To Connect The Scan Tool (M.U.T.-III)
2. Turn the ignition switch to the "LOCK" (OFF) position.
3. Check the ETACS data list.
- Close the driver's door.
- Close the passenger's door.
- Close the RH-side rear door.
- Close the LH-side rear door.
- Close the trunk lid.
- Remove the ignition key from the ignition key cylinder.







OK: Normal condition are displayed.

Q: Are the check result normal?

YES [Normal conditions are displayed for all the items.]: Go to Step 6.
NO [Normal condition is not displayed for item No. 256.]: Refer to Inspection Procedure 5: ETACS-ECU does not receive any signal from the front door switch (LH). Inspection Procedure 6
NO [Normal condition is not displayed for item No. 257.]: Refer to Inspection Procedure 6: ETACS-ECU does not receive any signal from the front door switch (RH). Inspection Procedure 5
NO [Normal condition is not displayed for item No. 258.]: Refer to Inspection Procedure 8: ETACS-ECU does not receive any signal from the rear door switch (RH). Inspection Procedure 8
NO [Normal condition is not displayed for item No. 259.]: Refer to Inspection Procedure 7: ETACS-ECU does not receive any signal from the rear door switch (LH). Inspection Procedure 7
NO [Normal condition is not displayed for item No. 260.]: Refer to Inspection Procedure 9: ETACS-ECU does not receive any signal from the trunk lid latch. Inspection Procedure 9
NO [Normal condition is not displayed for item No. 264.]: Refer to Inspection Procedure 3: ETACS-ECU does not receive any signal from the key reminder switch. Inspection Procedure 3

STEP 6. Retest the system.
Check if the keyless entry system works normally.

Q: Is the check result normal?

YES: Intermittent malfunction.

NO: Replace WCM and register the ID codes.