Keyless Operation System (KOS)

DTC B2101: IG SW start POS.circuit low
DTC B2102: IG SW start POS.circuit high

CAUTION:

- If the DTC B2101 or B2102 is set in KOS-ECU, always diagnose the CAN bus lines.
- Before replacing the ECU, ensure that the communication circuit is normal.

















DTC SET CONDITION

If the actual ignition switch status is different from the ignition switch status information received from ETACS-ECU via CAN, KOS-ECU sets the diagnostic trouble code No. B2101 or B2102.

TECHNICAL DESCRIPTION (COMMENT)

If the difference in the ignition switch level shown below occurs consecutively 10 times with the ignition switch being the ON position or START position, when the CAN message (ignition switch position information) from ETACS-ECU, KOS-ECU determines that there is a problem.
B2101

- Status of ignition switch: ON position
- Ignition switch position information: OFF
B2102

- Status of ignition switch: OFF position
- Ignition switch position information: ON

TROUBLESHOOTING HINTS

- Malfunction of CAN bus line
- Malfunction of the KOS-ECU
- Malfunction of the ignition switch
- Damaged wiring harness and connectors
- Malfunction of ETACS-ECU

DIAGNOSIS

Required Special Tools:

- 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 (Vehicles with CAN communication system)

STEP 1. Using scan tool MB991958, diagnose the CAN bus line.





(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 to the data link connector.
(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. Check ETACS-ECU connector C-317 and KOS-ECU connector C-05 for loose, corroded or damaged terminals, or terminals pushed back in the connector.

Q. Is ETACS-ECU connector C-317 and KOS-ECU connector C-05 in good condition?

YES Go to Step 3.
NO Repair the defective connector.
STEP 3. Check the wiring harness between KOS-ECU connector C-05 (terminal No.39) and ETACS-ECU connector C-317 (terminal No.5).

- Check the power supply line for open circuit.

NOTE:
Also check joint connector (1) C-101 for loose, corroded, or damaged terminals, or terminals pushed back in the connector. If joint connector (1) C-101 is damaged, repair or replace the damaged component(s) as described in Harness Connector Inspection Harness Connector Inspection.

Q. Is the wiring harness between KOS-ECU connector C-05 (terminal No. 39) and ETACS-ECU connector C-317 (terminal No. 5) in good condition?

YES Go to Step 4.
NO Repair the wiring harness.
STEP 4. Using scan tool MB991958, check data list.

Use the ETACS-ECU data list to check the signals related to the ignition voltage.

Turn the ignition switch from "LOCK" (OFF) position to "ON" position.





Q. Does scan tool MB991958 display the item "IG voltage" as normal condition?

YES Go to Step 5.
NO Diagnose the ETACS-ECU. Electronic Time and Alarm Control System (ETACS).
STEP 5. Recheck for diagnostic trouble code.

Check again if the DTC is set to the WCM.

(1)Erase the DTC.

(2)Turn the ignition switch from "LOCK" (OFF) position to "ON" position.

(3)Check if DTC is set.

(4)Turn the ignition switch to the "LOCK" (OFF) position.

Q. Is the DTC set?

YES Replace KOS-ECU and register the ID codes (Refer to ID registration procedure manual - ID codes registration judgement table).
NO The trouble can be an intermittent malfunction How to Cope With Intermittent Malfunctions).