How To Proceed With Troubleshooting

WARNING: This page is about a different car, the 2004 Lexus LS 430. However, it is still accessible from the selected car via links, so may be relevant.

Vehicle brought into a workshop
Diagnostic questioning and symptom confirmation (see CUSTOMER PROBLEM ANALYSIS CHECK )
Ask the customer about symptoms and confirm malfunctions. Fill out the Customer Problem Analysis check sheet.

The screen displays nothing (go to step 6 , proceed to "BLACK SCREEN (NO IMAGE APPEARS ON NAVIGATION/AUDIO SCREEN)")

Other symptoms (go to step 3)
Confirm the system normal condition (see HOW TO PROCEED WITH TROUBLESHOOTING )
Applicable (This is not a malfunction.)

Not applicable (go to step 4)
Check the diagnostic trouble codes (see DIAGNOSTIC TROUBLE CODE CHART )
HINT:
- If the system cannot enter the diagnosis mode, inspect each AVC-LAN communication signal and repair or replace problem parts (see AVC-LAN CIRCUIT (NAVIGATION ECU - STEREO COMPONENT TUNER) - AVC-LAN CIRCUIT (RADIO RECEIVER ASSY - MULTI-DISPLAY) ).
- Even if the malfunction symptom is not confirmed, check the diagnostic trouble codes. This is because the system stores past diagnostic trouble codes.
- Refer to the detailed description on the diagnostic screen, as necessary (see DIAGNOSIS DISPLAY DETAILED DESCRIPTION ).
- Check and clear the past diagnostic trouble code. Check the diagnostic trouble code and inspect the area the code indicates.
A code is output (go to step 5)

A code is not output (go to step 6)
Diagnostic trouble code chart (see DIAGNOSTIC TROUBLE CODE CHART )
Find the output code on the diagnostic trouble code chart.

Output the diagnostic trouble code (go to step 8)
Problem symptoms table (see PROBLEM SYMPTOMS TABLE )
Find the applicable symptom code in the problem symptoms table.

HINT:

If the symptom does not recur and no code is output, perform the symptom reproduction method (see HOW TO PROCEED WITH TROUBLESHOOTING ).

There is an applicable symptom code in the table (go to step 8)

There is no applicable symptom code in the table (go to step 7)
Check the ECU terminal arrangement based on the malfunction symptom (see TERMINALS OF ECU )
Check the circuit
Adjust, repair or replace as necessary.
Recheck the diagnostic trouble code (see DIAGNOSTIC TROUBLE CODE CHART )
HINT:

After deleting the DTC, recheck the diagnostic trouble code.
Perform confirmation test
END