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DTC U1109: Column SW LIN timeout


caution Before replacing the ECU, ensure that the communication circuit is normal.








TROUBLE JUDGMENT


The ETACS-ECU receives signal from the column switch. If signal cannot be received at all, DTC U1109 will be set.

TECHNICAL DESCRIPTION (COMMENT)


Current trouble
Past trouble

TROUBLESHOOTING HINTS



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. Check ETACS-ECU connectors C-301, C-317 and column switch connector C-212 for loose, corroded or damaged terminals, or terminals pushed back in the connector.

Q. Are ETACS-ECU connectors C-301, C-317 and column switch connector C-212 in good condition?
Go to Step 2.
Repair or replace the damaged component(s).

STEP 2. Check the ground circuit to the column switch. Measure the resistance at column switch connector C-212.
(1)Disconnect column switch connector C-212 and measure the resistance available at the wiring harness side of the connector.

(2)Measure the resistance value between column switch connector C-212 terminal 4 and ground.

  • The resistance should be 2 ohms or less.

Q. Is the measured resistance 2 ohms or less?

Go to Step 4.

Go to Step 3.

STEP 3. Check the wiring harness between column switch connector C-212 (terminal 4) and the ground.

  • Check the ground wires for open circuit.

Q. Is the wiring harness between column switch connector C-212 (terminal 4) and the ground in good condition?
No action is necessary and testing is complete.
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.

STEP 4. Check the battery power supply circuit to the column switch. Measure the voltage at column switch connector C-212.
(1)Disconnect column switch connector C-212 measure the voltage available at the wiring harness side of the connector.

(2)Measure the voltage between column switch connector C-212 terminal 1 and ground.

  • The voltage should measure approximately 12 volts (battery positive voltage).

Q. Is the measured voltage approximately 12 volts (battery positive voltage)?

Go to Step 6.

Go to Step 5.

STEP 5. Check the wiring harness between ETACS-ECU connector C-317 (terminal 10) and column switch connector C-212 (terminal 1).

  • Check the power supply line (battery supply) for open circuit and short circuit.

Q. Is the wiring harness between ETACS-ECU connector C-317 (terminal 10) and column switch connector C-212 (terminal 1) in good condition?
No action is necessary and testing is complete.
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.

STEP 6. Check the wiring harness between ETACS-ECU connector C-301 (terminal 1) and column switch connector C-212 (terminal 3).
Check the communication lines for open circuit.
note Also check joint connector C-102 for loose, corroded, or damaged terminals, or terminals pushed back in the connector. If joint connector C-102 is damaged, repair or replace the connector as described in GROUP 00E, Harness Connector Inspection .

Q. Is the wiring harness between ETACS-ECU connector C-301 (terminal 1) and column switch connector C-212 (terminal 3) in good condition?
Go to Step 7.
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.

STEP 7. Recheck for diagnostic trouble code.
Check again if the DTC is set to the ETACS-ECU.

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

Q. Is the DTC set?

Replace the lighting switch.

A poor connection, open circuit or other intermittent malfunction is present in the LIN bus lines between the column switch and the ETACS-ECU (Refer to GROUP 00, How to Cope with Intermittent Malfunction ).