Inspection Procedure 12
Inspection Procedure 12: 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 signal of the keyless operation key is sent to ETACS-ECU via KOS-ECU. Also, when ETACS receives signals from the all the door switches, ETACS-ECU judges them to activate the keyless entry function.
TROUBLESHOOTING HINTS
- Malfunction of CAN bus line
- Malfunction of the door switches
- Malfunction of the liftgate switch
- Malfunction of the keyless operation key
- Damaged wiring harness and connectors
- Malfunction of the KOS-ECU
- Malfunction of ETACS-ECU
DIAGNOSIS
STEP 1. Using scan tool MB991958, read CAN bus the diagnostic trouble code.
(1)
CAUTION:
To prevent damage to scan tool MB991958, always turn the power supply mode of the engine switch to the OFF position before connecting or disconnecting scan tool MB991958.
Connect scan tool MB991958. Refer to "How to connect scan too (M.U.T.-III) Reading and Clearing Diagnostic Trouble Codes."
(2)Turn the power supply mode of the engine switch to ON.
(3)Check whether the CAN bus lines related DTC is set.
(4)Turn the power supply mode of the engine switch to OFF.
Q. Is the DTC set?
YES Repair the CAN bus line Scan Tool Testing and Procedures).
NO Go to Step 2.
STEP 2. Using scan tool MB991958, read the diagnostic trouble code.
(1)
CAUTION:
To prevent damage to scan tool MB991958, always turn the power supply mode of the engine switch to the OFF position before connecting or disconnecting scan tool MB991958.
Connect scan tool MB991958. Refer to "How to connect scan too (M.U.T.-III) Reading and Clearing Diagnostic Trouble Codes."
(2)Turn the power supply mode of the engine switch to ON.
(3)Check whether the KOS-ECU related DTC is set.
(4)Turn the power supply mode of the engine switch to OFF.
Q. Is the DTC set?
YES Diagnose the KOS-ECU. Refer to diagnostic trouble code chart Keyless Operation System (KOS).
NO Go to Step 3.
STEP 3. Check the power supply system
With the power supply mode of the engine switch to OFF, check if the following function operates normally:
- Headlights
- 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.
Check that the central door locking system works normally.
Q. Is the check result normal?
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 power supply mode of the engine switch to the 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 power supply mode of the engine switch to OFF.
(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 liftgate.
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.] : 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.
STEP 6. Check with another registered keyless operation key.
Check that the keyless entry function can be used with another keyless operation key.
Q. Can the keyless entry function be used?
YES Replace the keyless operation key concerned and register the ID codes (Refer to ID Codes Registration Procedure).
NO Go to Step 7.
STEP 7. Check of the troubles
Replace ETACS-ECU. After the replacement, perform the coding, and check that the keyless entry system operates normally.
Q. Is the check result normal?
YES The diagnosis is complete.
NO Replace KOS-ECU and register the ID codes (Refer to ID Codes Registration Procedure).