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Problem Symptoms Table

WARNING: This page is about a different car, the 2008 Lexus LS 600hL. However, it is still accessible from the selected car via links, so may be relevant.

HINT.

If the normal codes for the pre-collision system and CAN communication system are output but the following problem symptoms are present, perform the malfunction diagnosis by following the "Suspected Area" procedures below.

Pre-collision system 

PROBLEM SYMPTOMS REFERENCE

Symptom Suspected Area See
"Check PCS system" is displayed Seat belt control ECU SEAT BELT CONTROL ECU 
Combination Meter REMOVAL
"PCS not Available Now" is displayed Pre-collision brake cancel switch is ON -
System determines obstacles cannot be detected due to front millimeter wave radar sensor or radiator grille being dirty If dirt is removed, normal control returns (Dirt history can be checked using DATA LIST) -
System determines wave radar sensor cannot detect obstacles due to bad weather If weather recovers, normal control returns (Bad weather history can be checked using DATA LIST) -
Overheating protection fail-safe of seat belt control ECU operates If ECU temperature drops, normal control returns -
Pre-collision brake cancel switch -
Wire harness between pre-collision brake cancel switch and driving support ECU -
Front millimeter wave radar sensor REMOVAL
Seat belt control ECU SEAT BELT CONTROL ECU 
Driving support ECU REMOVAL
Although there is possibility of collision, pre-collision control (all front collision controls) do not operate ("PCS not available now" is not displayed) Vehicle condition/environment does not match pre-collision control operation conditions (Confirm control operation conditions) -
Check installation condition of front millimeter wave radar sensor INSTALLATION
Perform front millimeter wave radar sensor adjustment ADJUSTMENT
Front millimeter wave radar sensor REMOVAL
Driving support ECU REMOVAL
Although there is no possibility of collision, pre-crash Check installation condition of front millimeter wave radar sensor INSTALLATION
Perform front millimeter wave radar sensor adjustment REMOVAL
Front millimeter wave radar sensor REMOVAL
Driving support ECU REMOVAL
Only pre-collision seat belt does not operate Buckle switch error (malfunction in which DTC is not output) -
Seat belt control ECU SEAT BELT CONTROL ECU 
Pre-collision brake cannot be canceled (pre-collision warning indicator does not blink) Combination meter (check if indicator blinks using ACTIVE TEST) DATA LIST / ACTIVE TEST
Pre-collision brake cancel switch -
Wire harness between pre-collision brake cancel switch and driving support ECU -
Driving support ECU REMOVAL