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DTC U0169: Sunroof LIN timeout <Vehicles with sunroof>


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






TROUBLE JUDGMENT


The ETACS-ECU receives signal from the sunroof motor assembly (sunroof-ECU). If signal cannot be received at all, DTC U0169 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 connector C-316 and sunroof motor assembly connector D-06 for loose, corroded or damaged terminals, or terminals pushed back in the connector.

Q. Are ETACS-ECU connector C-316 and sunroof motor assembly connector D-06 in good condition?
Go to Step 2.
Repair or replace the damaged component(s).

STEP 2. Check the ground circuit to the sunroof motor assembly. Measure the resistance at sunroof motor assembly connector D-06.
(1)Disconnect sunroof motor assembly connector D-06 and measure the resistance available at the wiring harness side of the connector.

(2)Measure the resistance value between sunroof motor assembly connector D-06 terminal 2 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 sunroof motor assembly connector D-06 (terminal 2) and the ground.

  • Check the ground wires for open circuit.

Q. Is the wiring harness between sunroof motor assembly connector D-06 (terminal 2) 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 sunroof motor assembly. Measure the voltage at sunroof motor assembly connector D-06.
(1)Disconnect sunroof motor assembly connector D-06 measure the voltage available at the wiring harness side of the connector.

(2)Measure the voltage between sunroof motor assembly connector D-06 terminal 6 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-316 (terminal 2) and sunroof motor assembly connector D-06 (terminal 6).

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

Q. Is the wiring harness between ETACS-ECU connector C-316 (terminal 2) and sunroof motor assembly connector D-06 (terminal 6) 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-316 (terminal 1) and sunroof motor assembly connector D-06 (terminal 7).
Check the communication lines for open circuit.

Q. Is the wiring harness between ETACS-ECU connector C-316 (terminal 1) and sunroof motor assembly connector D-05 (terminal 7) 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 sunroof motor assembly.

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