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.
OPERATION
The receiver antenna module receives 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 function.
PROBABLE CAUSES
- Malfunction of CAN bus line
- Malfunction of the door switches
- Malfunction of the key reminder switch
- Malfunction of the receiver antenna module
- Malfunction of the keyless operation key
- Damaged wiring harness and connectors
- Malfunction of the KOS-ECU
- Malfunction of ETACS-ECU
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. 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)Check whether the CAN bus lines related DTC is set.
(4)Turn the ignition switch to the "LOCK" (OFF) position.
Q. Is the DTC set?
YES Repair the CAN bus line CAN Bus Diagnostics Chart).
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 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. 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 is displayed.
Q. Is the check result normal?
YES (Normal conditions are displayed for all the items.) : Go to Step 5.
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 5. Check KOS-ECU connector C-102 and receiver antenna module connector C-30 for loose, corroded or damaged terminals, or terminals pushed back in the connector.
Q. Are KOS-ECU connector C-102 and receiver antenna module connector C-30 in good condition?
YES Go to Step 6.
NO Repair or replace the damaged component(s). Harness Connector Inspection. Check that the keyless entry function works normally.
STEP 6. Check the wiring harness between KOS-ECU connector C-102 (terminal Nos. 7, 9, 10 and 32) and receiver antenna module connector C-30 (terminal Nos. 12, 3, 4 and 8).
Q. Is the wiring harness between KOS-ECU connector C-102 (terminal Nos. 7, 9, 10 and 32) and receiver antenna module connector C-30 (terminal Nos. 12, 3, 4 and 8) in good condition?
YES Go to Step 7.
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 function works normally.
STEP 7. 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 8.
STEP 8. Check of the troubles
Replace ETACS-ECU. After the replacement, perform the coding, and check that the keyless entry function operates normally.
Q. Is the check result normal?
YES Intermittent malfunction is suspected How to Cope With Intermittent Malfunctions).
NO Replace KOS-ECU and register the ID codes (Refer to ID Codes Registration Procedure).