If
the diagnosis code No. B2101 or B2102 is set, be sure to diagnose the CAN bus line.
Before replacing the ECU, ensure that the communication circuit is normal.
TROUBLE JUDGMENT
WCM sets diagnosis code No. B2101 or B2012 when the actual state of the ignition switch and
the ignition switch position information received from ETACS-ECU via CAN do not match.
JUDGEMENT CRITERIA
WCM determines that the abnormality is present, if it has detected discrepancy in the
ignition switch level shown below ten consecutive times when WCM has received the CAN message
(ignition switch position information) from ETACS-ECU with the ignition switch turned to the
ON or START position. B2101
Status of ignition switch: OFF position
Ignition switch position information from the ETACS-ECU: ON
B2102
Status of ignition switch: ON position
Ignition switch position information from the ETACS-ECU: OFF
PROBABLE CAUSES
Malfunction of CAN bus line
Malfunction of the WCM
Malfunction of the ignition switch
Damaged wiring harness and connectors
Malfunction of ETACS-ECU
DIAGNOSIS 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 ).
On completion, go to Step 2.
STEP 3. Check the wiring harness between the C-317 ETACS-ECU connector
terminal No. 5 and the C-33 WCM connector terminal No. 9.
Check the power supply line for open circuit.
Q.
Is the check result normal?
Go to Step 4.
Repair the wiring harness.
STEP 4. M.U.T.-III other system data list
Use M.U.T.-III to check the ETACS-ECU service data. Refer to GROUP 54A -
ETACS -
Service
Data Reference Table .
Item 254: IG voltage
OK: Battery voltage
Q.
Is the check result normal?
Go to Step 5.
Perform troubleshooting for ETACS-ECU (Refer to GROUP 54A -
ETACS -
Troubleshooting).
STEP 5. Check whether the diagnosis code is reset.
(1)Erase the diagnosis code.
(2)Turn the ignition switch from the LOCK (OFF) position to the ON position.
(3)Check if the diagnosis code is set.
Q.
Is the diagnosis code set?
Replace WCM and register the ID codes (Refer to ).
Intermittent malfunction is suspected (Refer to GROUP 00 -
How to Use
Troubleshooting/Inspection Service Points -
How to Deal with Intermittent Malfunction ).
)
)
)
)
)
Go to Step 2.
Repair the CAN bus line (Refer to GROUP 54C -
Troubleshooting 
).
On completion, go to Step 2.