DESCRIPTION
WIRING DIAGRAM
INSPECTION PROCEDURE
CHECK PERSONAL LIGHT (OPERATION)
PERFORM ACTIVE TEST BY INTELLIGENT TESTER
CHECK HARNESS AND CONNECTOR (MAIN BODY ECU LH - OVERHEAD J/B)
CHECK HARNESS AND CONNECTOR (MAIN BODY ECU LH - OVERHEAD J/B)
CHECK HARNESS AND CONNECTOR (POWER SOURCE)
LIGHTING SYSTEM - Shift Illumination Circuit
DESCRIPTION
The turning on and off of the shift illumination is controlled by the main body ECU LH based on various signals received through BEAN communication.
The main body ECU LH includes a MOS-FET (Metal Oxide Semiconductor - Field Effect Transistor) circuit that fades the shift illumination in and out by duty control.
This MOS-FET circuit has an overheat protection function as a fail-safe. If the main body ECU LH becomes excessively hot, the shift illumination turns off and remains off.
Normal operation will resume when the conditions required to turn on the shift illumination are met again.
WIRING DIAGRAM
INSPECTION PROCEDURE
| 1.CHECK PERSONAL LIGHT (OPERATION) |
- The personal lights and shift illumination share the same power source circuit. Therefore, if none of them come on, inspect the power source circuit first.
Push the switches for the personal lights.
Check that the personal lights come on.
- OK:
- Personal lights come on.
| 2.PERFORM ACTIVE TEST BY INTELLIGENT TESTER |
Connect the intelligent tester to the DLC3.
Turn the engine switch on (IG).
Turn the intelligent tester main switch on.
Select the item(s) below in the ACTIVE TEST, and check the operation.
ACTIVE TEST: Body No. 3 (Main Body ECU LH)| Item | Test Details | Diagnostic Note |
| Shift Light Operation | Shift illumination ON / OFF | - |
- OK:
- The shift illumination comes on.
| OK | |
| |
| PROCEED TO NEXT CIRCUIT INSPECTION SHOWN IN PROBLEM SYMPTOMS TABLE |
|
| 3.CHECK HARNESS AND CONNECTOR (MAIN BODY ECU LH - OVERHEAD J/B) |
Disconnect the Q1 main body ECU LH connector.
Measure the voltage according to the value(s) in the table below.
- Standard voltage:
| Tester Connection | Condition | Specified Condition |
| Q1-3 (RCTY) - Body ground | Always | 10 to 14 V |
| OK | |
| |
| REPLACE MAIN BODY ECU LH (COWL SIDE J/B LH) |
|
| 4.CHECK HARNESS AND CONNECTOR (MAIN BODY ECU LH - OVERHEAD J/B) |
Disconnect the Q1 main body ECU LH connector.
Disconnect the R5 overhead J/B connector
Measure the resistance according to the value(s) in the table below.
- Standard resistance:
| Tester Connection | Condition | Specified Condition |
| Q1-3 (RCTY) - R5-14 (SHFT) | Always | Below 1 Ω |
| Q1-3 (RCTY) - Body ground | Always | 10 kΩ or higher |
| | REPAIR OR REPLACE HARNESS OR CONNECTOR |
|
|
| 5.CHECK HARNESS AND CONNECTOR (POWER SOURCE) |
Disconnect the R5 overhead J/B connector
Measure the voltage according to the value(s) in the table below.
- Standard voltage:
| Tester Connection | Condition | Specified Condition |
| R5-1 (+B1) - Body ground | Always | 10 to 14 V |
| | REPAIR OR REPLACE HARNESS OR CONNECTOR |
|
|
LEXUS IS250, IS220d / GSE20 ALE20
