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Inspection Procedure 12: Keyless entry system does not work.
 
 
cautionBefore 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)
cautionTo 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) ."
(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.
Is the DTC set?
Repair the CAN bus line (Refer to GROUP 54C, CAN bus diagnostics table ).
Go to Step 2.
 
STEP 2. Using scan tool MB991958, read the diagnostic trouble code.
(1)
cautionTo 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) ."
(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.
Is the DTC set?
Diagnose the KOS-ECU. Refer to diagnostic trouble code chart .
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
Is the check result normal?
Go to Step 4.
Refer to GROUP 54A - Malfunction of ETACS-ECU power supply circuit .
 
STEP 4. Verify the central door locking system.
Check that the central door locking system works normally.
Is the check result normal?
Go to Step 5.
Refer to GROUP 42A - Troubleshooting .
 
STEP 5. Using scan tool MB991958, check data list.
Check the signals related to the keyless entry system operation.
(1)
cautionTo 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) ."
(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.
 
Item No.Item nameNormal condition
Item 256Dr door ajar switchClose
Item 257As door ajar switchClose
Item 258RR door ajar switchClose
Item 259RL door ajar switchClose
Item 260Trunk/gate ajar switchClose
OK: Normal condition are displayed.
Are the check result normal?
<Normal conditions are displayed for all the items.> : Go to Step 6.
<Normal condition is not displayed for item No. 256.> : Refer to GROUP 54A, Inspection Procedure 5: ETACS-ECU does not receive any signal from the front door switch (LH) .
<Normal condition is not displayed for item No. 257.> : Refer to GROUP 54A, Inspection Procedure 6: ETACS-ECU does not receive any signal from the front door switch (RH) .
<Normal condition is not displayed for item No. 258.> : Refer to GROUP 54A, Inspection Procedure 8: ETACS-ECU does not receive any signal from the rear door switch (RH) .
<Normal condition is not displayed for item No. 259.> : Refer to GROUP 54A, Inspection Procedure 7: ETACS-ECU does not receive any signal from the rear door switch (LH) .
<Normal condition is not displayed for item No. 260.> : Refer to GROUP 54A, Inspection Procedure 9: ETACS-ECU does not receive any signal from the liftgate switch .
 
STEP 6. Check with another registered keyless operation key.
Check that the keyless entry function can be used with another keyless operation key.
Can the keyless entry function be used?
Replace the keyless operation key concerned and register the ID codes (Refer to ).
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.
Is the check result normal?
The diagnosis is complete.
Replace KOS-ECU and register the ID codes (Refer to ).