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DTC U1109 Column SW LIN timeout <Up to 19 Model year>
 
 
cautionBefore replacing the ECU, ensure that the communication circuit is normal.
 
 
JUDGMENT CRITERIA
The ETACS-ECU will set DTC U1109 when no signals are received from the column switch (integrated with column-ECU).
 
 
PROBABLE CAUSES
  • Faulty column switch
  • Malfunction of the LIN bus
 
 
DIAGNOSIS
Required Special Tools:
  • MB991223: Harness Set
  • MB992006: Extra Fine Probe
STEP 1. Resistance measurement at the column switch connector
(1) Disconnect the connector, and measure at the wiring harness side.
(2) Measure the resistance between the column switch connector (GND terminal) and the body ground.
OK: The resistance should be 2 ohms or less
Is the check result normal?
Go to Step 3.
Go to Step 2.
 
STEP 2. Check of open circuit in body ground line between column switch connector (GND terminal) and the body ground.
Is the check result normal?
The trouble can be an intermittent malfunction (Refer to GROUP 00 - How to use Troubleshooting/inspection Service Points - How to Cope with Intermittent Malfunction ).
Repair the connector(s) or wiring harness.
 
STEP 3. Voltage measurement at the column switch connector.
(1) Disconnect the connector, and measure at the wiring harness side.
(2) Measure the voltage between the column switch connector (+B terminal) and the body ground.
OK: The voltage should measure approximately 12 volts (battery positive voltage).
Is the check result normal?
Go to Step 5.
Go to Step 4.
 
STEP 4. Check of short to power supply, short to ground, and open circuit in +B line between ETACS-ECU connector and column switch connector.
Is the check result normal?
The trouble can be an intermittent malfunction (Refer to GROUP 00 - How to use Troubleshooting/inspection Service Points - How to Cope with Intermittent Malfunction ).
Repair the connector(s) or wiring harness.
 
STEP 5. Check of open circuit in DATA line between ETACS-ECU connector and column switch connector.
Is the check result normal?
Go to Step 6.
Repair the connector(s) or wiring harness.
 
STEP 6. Check whether the DTC is set again.
Check again if the DTC is set in the ETACS-ECU.
(1) Erase the DTC.
(2) Turn the ignition switch from "LOCK" (OFF) position to "ON" position.
(3) Check if DTC is set.
Is the DTC set?
Replace the column switch (Refer to GROUP 54A - Column switch ).
A poor connection, open circuit, or other intermittent malfunctions in the LIN bus lines between the column switch and the ETACS-ECU (Refer to GROUP 00 - How to Cope with Intermittent Malfunction ).