Inspection Procedure 1

INSPECTION PROCEDURE 1: Sunroof does not work at All.

CAUTION:
Before replacing the ECU, ensure that the power supply circuit, the ground circuit and the communication circuit are normal.

CIRCUIT OPERATION

Malfunctions of the sunroof motor assembly power supply/ground system, sunroof motor assembly, or sunroof switch are suspected.

TROUBLESHOOTING HINTS

- The sunroof switch may be defective
- 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

DIAGNOSTIC PROCEDURE

Required Special Tools:

- MB992006: Extra fine probe
- MB991223: Harness set
- 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

STEP 1. Using scan tool MB991958, read CAN bus diagnostic trouble code.

(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 scan tool (M.U.T.-III) Reading and Clearing Diagnostic Trouble Codes."
(2)Turn the ignition switch to the "ON" position.
(3)Check whether the sunroof motor assembly related DTC is set.
(4)Turn the ignition switch to the "LOCK" (OFF) position.

Q. Is the DTC set?

YES Diagnose the sunroof motor assembly. Refer to Sunroof System.

NO Go to Step 3.

STEP 3. Check sunroof switch connector D-04 for loose, corroded or damaged terminals, or terminals pushed back in the connector.

Q. Is sunroof switch connector D-04 in good condition?

YES Go to Step 4.
NO Repair or replace the damaged component(s). Harness Connector Inspection. Check that the sunroof works normally.
STEP 4. Sunroof switch check

(1)Remove the sunroof switch. Refer to Removal and Replacement.

(2)Check continuity when the sunroof switch is operated to "OPEN", "TILT-UP" or "CLOSE/TILT-DOWN"
position.

Q. Is the sunroof switch normal?

YES Go to Step 5.

NO Replace the sunroof switch. Check that the sunroof works normally.

STEP 5. Check the ground circuit to the sunroof motor assembly. Measure the resistance at sunroof switch connector D-04.

(1)Disconnect sunroof switch connector D-04 and measure the resistance available at the wiring harness side of the connector.

(2)Measure the resistance value between terminal 4 and ground.

- The resistance should be 2 ohms or less.

Q. Is the measured resistance 2 ohms or less?

YES Go to Step 6.

NO Go to Step 8.

STEP 6. Check sunroof motor assembly connector D-05 for loose, corroded or damaged terminals, or terminals pushed back in the connector.

Q. Is sunroof motor assembly connector D-05 in good condition?

YES Go to Step 7.
NO Repair or replace the damaged component(s). Harness Connector Inspection. Check that the sunroof works normally.
STEP 7. Check the wiring harness between sunroof switch connector D-04 (terminal 4) and sunroof motor assembly connector D-05 (terminal 1).

Q. Is the wiring harness between sunroof switch connector D-04 (terminal 4) and sunroof motor assembly connector D-05 (terminal No. 1) in good condition?

YES No action is necessary and testing is complete.
NO 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. Check that the sunroof works normally.
STEP 8. Check sunroof motor assembly connector D-05 for loose, corroded or damaged terminals, or terminals pushed back in the connector.

Q. Is sunroof motor assembly connector D-05 in good condition?

YES Go to Step 9.
NO Repair or replace the damaged component(s). Harness Connector Inspection. Check that the sunroof works normally.
STEP 9. Check the ground circuit to the sunroof motor assembly. Measure the resistance at sunroof motor assembly connector D-05.

(1)Disconnect sunroof motor assembly connector D-05 and measure the resistance available at the wiring harness side of the connector.

(2)Measure the resistance value between terminal 2 and ground.

- The resistance should be 2 ohms or less.

Q. Is the measured resistance 2 ohms or less?

YES Go to Step 11.

NO Go to Step 10.

STEP 10. Check the wiring harness between sunroof motor assembly connector D-05 (terminal 2) and ground.

Q. Is the wiring harness between sunroof motor assembly connector D-05 (terminal 2) and ground in good condition?

YES No action is necessary and testing is complete.
NO 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. Check that the sunroof works normally.
STEP 11. Check the fusible link (34) line of power supply circuit to the sunroof motor assembly. Measure the voltage at sunroof motor assembly connector D-05.

(1)Disconnect sunroof motor assembly connector D-05 and measure the voltage available at the wiring harness side of the connector.

(2)Measure the voltage between 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)?

YES Go to Step 13.

NO Go to Step 12.

STEP 12. Check the wiring harness between sunroof motor assembly connector D-05 (terminal 6) and fusible link (34).

NOTE:
Also check ETACS-ECU connectors C-309 and C-316 for loose, corroded, or damaged terminals, or terminals pushed back in the connector. If ETACS-ECU connectors C-309 and C-316 is damaged, repair or replace the damaged component(s) as described in Harness Connector Inspection Harness Connector Inspection.

Q. Is the wiring harness between sunroof motor assembly connector D-05 (terminal 6) and fusible link (34) in good condition?

YES No action is necessary and testing is complete.
NO 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. Check that the sunroof works normally.
STEP 13. Retest the system.

Check that the sunroof works normally.

Q. Is the check result normal?

YES No action is necessary and testing is complete.
NO Replace the sunroof motor assembly. Check that the sunroof works normally.