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DTC U0169 Sun roof LIN timeout <Vehicles with sunroof>
 
 
cautionBefore replacing the ECU, ensure that the communication circuit is normal.
 
 
JUDGMENT CRITERIA
The ETACS-ECU will set DTC U0169 when no signals are received from the sunroof motor assembly.
 
 
PROBABLE CAUSES
  • Faulty sunroof motor assembly
  • Malfunction of the LIN bus
 
 
DIAGNOSIS
Required Special Tools:
  • MB991223: Harness Set
  • MB992006: Extra Fine Probe
STEP 1. Resistance measurement at the sunroof motor assembly connector
(1) Disconnect the connector, and measure at the wiring harness side.
(2) Measure the resistance between the sunroof motor assembly connector (ground 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 sunroof motor assembly 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 3. Voltage measurement at the sunroof motor assembly connector.
(1) Disconnect the connector, and measure at the wiring harness side.
(2) Measure the voltage between the sunroof motor assembly connector (power supply 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 SR+ line between ETACS-ECU connector and sunroof motor assembly 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 LIN2 line between ETACS-ECU connector and sunroof motor assembly 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 the "LOCK" (OFF) position to the "ON" position.
(3) Check if DTC is set.
Is the DTC set?
Replace the sunroof motor assembly (Refer to GROUP 42A - Sunroof Assembly ).
A poor connection, open circuit, or other intermittent malfunctions in the LIN bus lines between the sunroof motor assembly and the ETACS-ECU (Refer to GROUP 00 - How to Cope with Intermittent Malfunction ).