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.

OPERATION
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.

PROBABLE CAUSES
- Malfunction of the key reminder switch
- Malfunction of the door switches
- Malfunction of keyless entry transmitter
- Malfunction of the WCM
- Malfunction of ETACS-ECU
- Damaged wiring harness and connectors
- Option coding information

DIAGNOSTIC PROCEDURE

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
- MB991910: M.U.T.-III Main Harness A

STEP 1. Scan tool (M.U.T.-III) CAN bus diagnostics

Use scan tool MB991958 (M.U.T.-III), diagnose the CAN bus lines.

Q: Is the CAN bus normal?

YES : Go to Step 2.

NO : Repair the CAN bus line.

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:
- Headlight
- Hazard warning light

Q: Is the check result normal?

YES : Go to Step 4.

NO : Refer to Malfunction of ETACS-ECU power supply circuit. Diagnostic Trouble Code Descriptions

STEP 4. Verify the central door locking system.

Q: Does the central door locking system work normally?

YES : Go to Step 5.

NO : Refer to Trouble Symptom Chart. 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 "ON" position.
3. Check the ETACS data list.
- Turn the ignition switch to the LOCK (OFF) position.
- Close the driver's door.
- Close the passenger's door.
- Close the RH-side rear door.
- Close the LH-side rear door.
- Close the liftgate.
- Remove the ignition key from the ignition key cylinder.







4. Turn the ignition switch to the "LOCK" (OFF) position.

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. 254.) : Refer to Inspection Procedure 2: ETACS-ECU does not receive any signal from the ignition switch (IG1). Inspection Procedure 2

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 5

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 6

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 liftgate switch. 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.