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DTC U0231 RLS LIN timeout <Vehicles with lighting control sensor (From 20 Model year)>
 
 
cautionBefore replacing the ECU, ensure that the communication circuit is normal.
 
 
JUDGMENT CRITERIA
The ETACS-ECU will set DTC U0231 when no signals are received from the lighting control sensor.
 
 
PROBABLE CAUSES
  • Faulty lighting control sensor
  • Malfunction of the LIN bus
 
 
DIAGNOSIS
Required Special Tools:
  • MB991223: Harness Set
  • MB992006: Extra Fine Probe
STEP 1. Using scan tool (M.U.T.-IIISE), read the DTC.
(1)
cautionTo prevent damage to scan tool (M.U.T.-IIISE), always turn the ignition switch to the "LOCK" (OFF) position before connecting or disconnecting scan tool (M.U.T.-IIISE).
Connect scan tool (M.U.T.-IIISE). Refer to "How to connect the Scan Tool (M.U.T.-IIISE) ."
(2) Check whether the following DTC are set in the ETACS-ECU.
  • U0169 <Vehicles with sunroof>
  • U1109
Is the DTC set?
Check the LIN bus line system. (Refer to ).
Go to Step 2.
 
STEP 2. Resistance measurement at the lighting control sensor connector
(1) Disconnect the connector, and measure at the wiring harness side.
(2) Measure the resistance between the lighting control sensor connector (ground terminal) and the body ground.
OK: The resistance should be 2 ohms or less
Is the check result normal?
Go to Step 4.
Go to Step 3.
 
STEP 3. Check of open circuit in body ground line between lighting control sensor connector (ground 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 4. Voltage measurement at the lighting control sensor connector.
(1) Disconnect the connector, and measure at the wiring harness side.
(2) Measure the voltage between the lighting control sensor connector (power supply terminal) and the body ground.
OK: OK: The voltage should measure approximately 12 volts (battery positive voltage).
Is the check result normal?
Go to Step 6.
Go to Step 5.
 
STEP 5. Check of short to power supply, short to ground, and open circuit in BUP1 line between ETACS-ECU connector and lighting control sensor 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 6. Check of open circuit in LIN2 line between ETACS-ECU connector and lighting control sensor connector.
Is the check result normal?
Go to Step 7.
Repair the connector(s) or wiring harness.
 
STEP 7. 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 the "LOCK" (OFF) position to the "ON" position.
(3) Check if DTC is set.
Is the DTC set?
Replace the lighting control sensor (Refer to GROUP 54A - Lighting Control Sensor ).
A poor connection, open circuit, or other intermittent malfunctions in the LIN bus lines between the lighting control sensor and the ETACS-ECU (Refer to GROUP 00 - How to Cope with Intermittent Malfunction ).