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 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

- Malfunction of CAN bus line
- Malfunction of the door switches
- Malfunction of the key reminder switch
- Malfunction of the receiver antenna assembly
- Malfunction of the keyless operation key
- Damaged wiring harness and connectors
- Malfunction of the KOS-ECU
- Malfunction of ETACS-ECU

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) Reading and Clearing Diagnostic Trouble Codes".
(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?

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

Q. Is the DTC set?

YES Diagnose the KOS-ECU. Refer to Keyless Operation System (KOS).

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:

- 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 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 "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.





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.

NO [Normal condition is not displayed for item No. 264.] : Inspection Procedure 3.

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?

YES Go to Step 7.
NO Repair or replace the damaged component(s). 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 intermediate connector C-41 for loose, corroded, or damaged terminals, or terminals pushed back in the connector. If intermediate connector C-41 is damaged, repair or replace the damaged component(s) as described in Harness Connector Inspection 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?

YES Go to Step 8.
NO 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?

YES Replace the keyless operation key concerned and register the ID codes (Refer to ID registration procedure manual - ID codes registration judgement table).
NO 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?

YES The diagnosis is complete.
NO Replace KOS-ECU and register the ID codes (Refer to ID registration procedure manual - ID codes registration judgement table).