INSPECTION
PROCEDURE 13: Keyless Entry System does not Work.
caution
Before replacing the ECU,
ensure that the power supply circuit, the earth 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 system.
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
STEP 1. M.U.T.-III CAN bus diagnostics
Use M.U.T.-III to diagnose the CAN bus lines.
Q.
Is the check result normal?
Go to Step 2.
Repair the CAN bus line (Refer to GROUP 54C -
Troubleshooting ).
STEP 2. M.U.T.-III diagnosis code
Check whether a KOS-related diagnosis code is set.
Q.
Is the diagnosis code set?
Refer to .
Go to Step 3.
STEP 3. Key reminder switch check
(1)Disconnect the C-315 ETACS-ECU connector.
(2)Measure the resistance at the harness-side connector with the ignition key removed
from the ignition key cylinder.
(3)Check the continuity between the C-315 ETACS-ECU connector terminal No. 13 and
the earth. OK: Continuity exists (2 Ω
or less)
Q.
Is the check result normal?
Go to Step 4.
Check the C-211 key reminder switch connector, the C-315 ETACS-ECU connector,
the wiring harness between the C-211 key reminder switch connector (terminal No. 3) and the
C-315 ETACS-ECU connector (terminal No. 13), and between the C-211 key reminder switch connector (terminal
No. 2) and the earth. If they are normal, replace the key reminder switch.
STEP 4. M.U.T.-III other system data list
Check for the signals related to the keyless entry system of ETACS.
(1)Turn the ignition switch to the ON position.
(2)Open each door and tailgate from the closed state.
Item No.
Item name
Normal conditions
Item 256
Dr door ajar switch
Open →
Close
Item 257
As door ajar switch
Open →
Close
Item 258
RR door ajar switch
Open →
Close
Item 259
RL door ajar switch
Open →
Close
Item 260
Trunk/gate trunk ajar switch
Open →
Close
OK: Normal conditions are displayed for all the items.
Q.
Are 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. 256.> : Refer to GROUP 54A -
inspection procedure 5: front door switch (driver’s
side) signal is not received .
NO <Normal condition is not displayed for item No. 257.> : Refer to GROUP 54A -
inspection procedure 6: front door switch (passenger’s side)
signal is not received .
NO <Normal condition is not displayed for item No. 258.> : Refer to GROUP 54A -
Inspection procedure 7: rear door switch (RH) signal
is not received .
NO <Normal condition is not displayed for item No. 259.> : Refer to GROUP 54A -
inspection procedure 8: rear door switch (LH) signal
is not received .
NO <Normal condition is not displayed for item No. 260.> : Refer to GROUP 54A -
inspection procedure 9: tailgate latch signal is
not received .
STEP 6. Check the wiring harness between the C-34 receiver antenna
module connector terminal Nos. 1, 2, 8, 12 and the C-104 KOS-ECU connector terminal Nos. 12,
11, 32, 7.
Check the communication and earth lines for open circuit or short circuit.
Q.
Is the check result normal?
Go to Step 7.
Repair the wiring harness.
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?
Replace the keyless operation key concerned and register the ID codes (Refer to ).
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 system operates normally.
Q.
Is the check result normal?
Intermittent malfunction is suspected (Refer to GROUP 00 -
How to Use Troubleshooting/Inspection
Service Points -
How to Cope with Intermittent Malfunction ).
Replace KOS-ECU and register the ID codes (Refer to ).
)
)
)
)
)
)
)
Go to Step 2.
Repair the CAN bus line (Refer to GROUP 54C -
Troubleshooting 
).
: Go to Step 5.