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Inspection Procedure 14: 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 receiver antenna module assembly lock and unlock signals from the keyless operation key, and sends them to KOS-ECU, and further to ETACS-ECU. Also, when ETACS receives signals from the key reminder switch and all the door switches, ETACS-ECU judges them to activate the keyless entry system.

TROUBLESHOOTING HINTS



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, read CAN bus 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) ."
(2)Turn the ignition switch to the "ON" position.
(3)Diagnose the CAN bus line.
(4)Turn the ignition switch to the "LOCK" (OFF) position.

Q. Is the CAN bus line found to be normal?

Go to Step 2.

Repair the CAN bus line (Refer to GROUP 54C, Diagnosis ).

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) ."
(2)Turn the ignition switch to the "ON" position.
(3)Check whether the KOS-ECU related DTC is set.
(4)Turn the ignition switch to the "LOCK" (OFF) position.

Q. Is the DTC set?

Diagnose the KOS-ECU. Refer to .

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:

  • Headlights
  • Hazard warning light

Q. 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.

Q. 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)
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) ."
(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.
Item No.
 Item name
 Normal condition
Item 256
 Dr door ajar switch
 Close
Item 257
 As door ajar switch
 Close
Item 258
 RR door ajar switch
 Close
Item 259
 RL door ajar switch
 Close
Item 260
 Trunk/gate trunk ajar switch
 Close
Item 264
 Handle lock switch
 Key in → Key out
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 GROUP 54A, Inspection Procedure 5: ETACS-ECU does not receive any signal from the front door switch (LH) .

NO <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) .

NO <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) .

NO <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) .

NO <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 trunk lid latch. .

NO <Normal condition is not displayed for item No. 264.> : Refer to GROUP 54A, Inspection Procedure 3: ETACS-ECU does not receive any signal from the key reminder switch. .

STEP 6. Check KOS-ECU connector C-05 and receiver antenna assembly connector D-14 for loose, corroded or damaged terminals, or terminals pushed back in the connector.

Q. Are KOS-ECU connector C-05 and receiver antenna assembly connector D-14 in good condition?
Go to Step 7.
Repair or replace the damaged component(s). Refer to GROUP 00E, Harness Connector Inspection . Check that the keyless entry system works normally.

STEP 7. Check the wiring harness between KOS-ECU connector C-05 (terminal Nos. 7, 9, 12, 13 and 32) and receiver antenna assembly connector D-14 (terminal Nos. 12, 3, 1, 5 and 8).

  • Check the communication and ground lines for open circuit or short circuit.
note Also check joint connector (6) C-16 and intermediate connector C-41 for loose, corroded, or damaged terminals, or terminals pushed back in the connector. If joint connector (6) C-16 and intermediate connector C-41 is damaged, repair or replace the damaged component(s) as described in GROUP 00E, Harness Connector Inspection .

Q. Are the wiring harness between KOS-ECU connector C-05 (terminal Nos. 7, 9, 12, 13 and 32) and receiver antenna assembly connector D-14 (terminal Nos. 12, 3, 1, 5 and 8) in good condition?
Go to Step 8.
The wiring harness may be damaged or the connector(s) may have loose, corroded or damaged terminals, or terminals pushed back in the connector. Repair the wiring harness as necessary. Check that the keyless entry system works normally.

STEP 8. 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?
Replace the keyless operation key concerned and register the ID codes (Refer to ).
Go to Step 9.

STEP 9. Check of the troubles
Replace receiver antenna assembly. After the replacement, perform the coding, and check that the keyless entry system operates normally.

Q. Is the check result normal?
The diagnosis is complete.
Replace KOS-ECU and register the ID codes (Refer to ).