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 CAN Bus Diagnostics Chart).
STEP 2. Using scan tool MB991958, read the diagnostic trouble code.
(1)
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.
Connect scan tool MB991958. Refer to "How to connect scan tool (M.U.T.-III) Reading and Clearing Diagnostic Trouble Codes."
(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. Electronic Time and Alarm Control System (ETACS).
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 Symptom Procedures.
STEP 4. Verify the central door locking system.
Q. Does the central door locking system work normally?
YES Go to Step 5.
NO Symptom Chart.
STEP 5. Using scan tool MB991958, check data list.
Check the signals related to the keyless entry system operation.
(1)
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.
Connect scan tool MB991958. Refer to "How to connect the Scan Tool (M.U.T.-III) Reading and Clearing Diagnostic Trouble Codes."
(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.) : Inspection Procedure 2.
NO (Normal condition is not displayed for item No. 256.) : Inspection Procedure 6.
NO (Normal condition is not displayed for item No. 257.) : Inspection Procedure 5.
NO (Normal condition is not displayed for item No. 258.) : Inspection Procedure 8.
NO (Normal condition is not displayed for item No. 259.) : Inspection Procedure 7.
NO (Normal condition is not displayed for item No. 260.) : Inspection Procedure 9.
NO (Normal condition is not displayed for item No. 264.) : 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 How to Cope With Intermittent Malfunctions).
NO Replace WCM and register the ID codes (Refer to ID Codes Registration Procedure).