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DTC U0169 Sunroof LIN timeout <Vehicles with sunroof>
 
 
cautionBefore replacing the ECU, ensure that the communication circuit is normal.
 
 
TROUBLE JUDGMENT
The ETACS-ECU receives signal from the sunroof motor assembly. If signal cannot be received at all, DTC U0169 will be set.
 
 
TROUBLESHOOTING HINTS
  • The sunroof motor assembly may be defective.
  • The wiring harness or connectors may have loose, corroded, or damaged terminals, or terminals pushed back in the connector.
 
 
DIAGNOSIS
Required Special Tools:
  • MB991223: Harness Set
  • MB992006: Extra Fine Probe
STEP 1. Using scan tool (M.U.T.-IIISE), read the ETACS-ECU diagnostic trouble code
(1)
cautionTo prevent damage to scan tool (M.U.T.-IIISE), always turn the electric motor switch to the 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 is set in the ETACS-ECU.
  • U0215
  • U0231
  • U1109
Is the DTC set?
Check the LIN bus line system. (Refer to ).
Go to Step 2.
 
STEP 2. 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 (E terminal) and the 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 E line between sunroof motor assembly connector and 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 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 (SR+ terminal) and the ground.
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 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 6. Check of open circuit in LIN2 line between ETACS-ECU connector and sunroof motor assembly connector.
Is the check result normal?
Go to Step 7.
Repair the connector(s) or wiring harness.
 
STEP 7. Recheck the DTC.
Check again if the DTC is set in the ETACS-ECU.
(1)
cautionTo prevent damage to scan tool (M.U.T.-IIISE), always turn the electric motor switch to the OFF 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) Erase the DTC.
(3) Turn the power supply mode of the electric motor switch from OFF to ON.
(4) Check if the DTC is set.
Is DTC set?
Replace the sunroof motor 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 ).