Trouble Shooting: Notes

WARNING: This page is about a different car, the 2002 Lexus GS 430 and 2002 Lexus GS 300. However, it is still accessible from the selected car via links, so may be relevant.

NOTE: The moon roof ECU is connected to the multiplex communication system.

Trouble shooting of a power moon roof system complaint begins with verification of the customer problem. If problem occurs, go to step 3. If problem does not occur, go to next step.
If problem does not occur, review conditions under which problem occurred for customer and try to duplicate those conditions. For example, if the problem occurs on rainy days or during high humidity conditions, sprinkle water onto vehicle and see if malfunction occurs. DO NOT sprinkle water directly into engine compartment or onto electronic components. Visually inspect for signs of mechanical and electrical damage. Inspect for blown fuses and damaged relays. Inspect for loose or corroded connections, damaged wiring harnesses and/or switches. Check for a broken or partially broken wire inside insulation, which could cause system malfunction but prove good in a continuity/voltage check with system disconnected. Ensure any aftermarket electronic equipment is properly installed. If fault is found, repair as necessary.
Inspect the multiplex communication system and confirm that there is no trouble by the basic inspection and DTC check. See PRE-CHECK under SELF-DIAGNOSTIC in MULTIPLEX COMMUNICATION SYSTEM article under COMMUNICATION DEVICES in ACCESSORIES & EQUIPMENT.

Determine problem symptom. See PROBLEM SYMPTOM INDEX table.

PROBLEM SYMPTOM INDEX

Symptom

Suspected Area ⁽¹⁾

Moon Roof Control System Does Not Operate

⁽²⁾⁽³⁾⁽⁴⁾⁽⁵⁾

Moon Roof Operates Abnormally (Stops Half Way, Moon Roof During Close Operation)

⁽⁴⁾⁽⁶⁾

Jam Protection System Does Not Operate

⁽⁵⁾

⁽¹⁾	Perform test procedures in order listed under suspected area.

⁽²⁾	Check the S/ROOF (25-amp) fuse located in the passenger side junction block.

⁽³⁾	Check the ECU-IG (15-amp) fuse located in the driver side junction block.

⁽⁴⁾	Check the moon roof control switch circuit. See MOON ROOF CONTROL SWITCH CIRCUIT under CIRCUIT TESTS.

⁽⁵⁾	Check the moon roof gear assembly with ECU circuit. See MOON ROOF GEAR ASSEMBLY WITH ECU CIRCUIT under CIRCUIT TESTS.

⁽⁶⁾	Check the moon roof pulse plate circuit. See MOON ROOF PULSE PLATE CIRCUIT under CIRCUIT TESTS.

Inspect the power moon roof circuits. See CIRCUIT TESTS .
After repairs have been completed, confirm that problem has been eliminated. Operate the system under same conditions recorded for original complaint. If problem is no longer present, repair has corrected problem. If problem is still present, further diagnosis and repair is required.