B2409

DTC B2409 STL Unit Comm.(No Response)

CAUTION:
- If DTC B2409 is set, diagnose the CAN bus lines.
- Whenever the steering lock unit is replaced, ensure that the communication circuit is normal.

Key Reminder Switch And KOS-ECU Circuit (Part 1):

Key Reminder Switch And KOS-ECU Circuit (Part 2):

DTC SET CONDITION
When the ignition push switch is pressed, the steering lock unit communicates with KOS-ECU to unlock the IG knob. If the steering lock unit communication error (no response) occurs at this time, the DTC is set.

TECHNICAL DESCRIPTION (COMMENT)
When the IG knob unlock communication is performed by pressing the ignition push switch, if the steering lock unit communication error (no response) occurs, the steering lock unit is judged as abnormal.

TROUBLESHOOTING HINTS
- Malfunction of the key reminder switch (integrated into the steering lock unit)
- Wiring harness or connector failure of CAN bus line
- Malfunction of the KOS-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

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







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).

1. 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.

STEP 2. Check key reminder switch connector C-211 and KOS-ECU connector C-05 for loose, corroded or damaged terminals, or terminals pushed back in the connector.

Q: Is the key reminder switch connector C-211 and KOS-ECU connector C-05 in good condition?

YES : Go to Step 3.

NO : Repair the defective connector.

STEP 3. Wiring harness check between C-211 key reminder switch connector and C-05 KOS-ECU connector for open circuit.

1. Disconnect C-211 key reminder switch connector and C-05 KOS-ECU connector.
2. Measure at the connector side of C-211 key reminder switch connector and C-05 KOS-ECU connector.
3. Measure the resistance between the terminals.







- C-211 key reminder switch connector terminal No.9 -C-05 KOS-ECU connector terminal No.5.







- C-211 key reminder switch connector terminal No.11 -C-05 KOS-ECU connector terminal No.31.







- C-211 key reminder switch connector terminal No.12 -C-05 KOS-ECU connector terminal No.4.

OK: Continuity exists (2 ohms or less)

Q: Is the check result normal?

YES : Go to Step 4.

NO (C-211 key reminder switch connector terminal No.9 -C-05 KOS-ECU connector terminal No.5.) : An open circuit is present in the wiring harness between C-211 key reminder switch connector terminal No.9 and C-05 KOS-ECU connector terminal No.5. Repair the wiring harness.

NO (C-211 key reminder switch connector terminal No.11 -C-05 KOS-ECU connector terminal No.31.) : An open circuit is present in the wiring harness between C-211 key reminder switch connector terminal No.11 and C-05 KOS-ECU connector terminal No.31. Repair the wiring harness.

NO (C-211 key reminder switch connector terminal No.12 -C-05 KOS-ECU connector terminal No.4.) : An open circuit is present in the wiring harness between C-211 key reminder switch connector terminal No.12 and C-05 KOS-ECU connector terminal No.4. Repair the wiring harness.

STEP 4. Check the wiring harness between the C-211 key reminder switch connector (terminal Nos. 9, 11, 12) and the ground for short circuit.

1. Disconnect C-211 key reminder switch connector, and check the wiring harness.







2. Check the wiring harness between C-211 key reminder switch connector (terminal No.9) and ground

OK: No Continuity







3. Check the wiring harness between C-211 key reminder switch connector (terminal No.11) and ground

OK: No Continuity







4. Check the wiring harness between C-211 key reminder switch connector (terminal No.12) and ground

OK: No Continuity

Q: Is the wiring harness between C-211 key reminder switch connector (terminal No.9, 11, 12) and the ground in good condition?

YES : Go to Step 5.


NO (key reminder switch connector C-211 terminal No.9 - ground.) : Repair the wiring harness between C-211 key reminder switch connector (terminal No.9) and the ground.

NO (key reminder switch connector C-211 terminal No.11 - ground.) : Repair the wiring harness between C-211 key reminder switch connector (terminal No.11) and the ground.

NO (key reminder switch connector C-211 terminal No.12 - ground.) : Repair the wiring harness C-211 key reminder switch connector (terminal No.12) and the ground.

STEP 5. Replace the key reminder switch, and check whether the diagnostic trouble code is reset.

1. Erase the DTC.
2. Turn the ignition switch from the "LOCK" (OFF) position to the "ON" position.
3. Check if the DTC is set.

Q: Is the DTC set?

YES : Replace KOS-ECU and register the ID codes.

NO : The trouble can be an intermittent malfunction.