LEMON Manuals: Even more car manuals for everyone: 1960-2025
Home >> Lexus >> 2003 >> LS 430 >> Repair and Diagnosis >> External Pages >> Different car >> Section 321 (Body Control Systems - Diagnostics) >> Problem Symptoms >> Theft Deterrent System
April 5, 2026: LEMON Manuals is launched! Read the announcement.

Theft Deterrent System

WARNING: This page is about a different car, the 2002 Toyota Sequoia. However, it is still accessible from the selected car via links, so may be relevant.
THEFT DETERRENT SYSTEM

Symptom/Suspect Area See
No Alerting Condition Is Operated (the System Cannot Be Set)
Security Indicator Circuit (1)
Key Unlock Warning Switch Circuit (2)
Courtesy Switch Circuit (3)
Door Unlock Detection Switch Circuit (Driver's) (4)
Door Unlock Detection Switch Circuit (Passenger's) (5)
Engine Hood Courtesy Switch Circuit (6)
Back Door Courtesy Switch Circuit (7)
Back Door ECU (8)
Body ECU (8)
Cannot Be Canceled When IG Is On With A Key
Key Unlock Warning Switch Circuit (2)
Ignition Switch (9)
Body ECU (8)
Cannot Be Canceled When Unlocking Back Door With A Key
Back Door ECU (8)
Body ECU (8)
Part Of System Does Not Operate (Headlight Does Not Light Up)
Headlight Relay Circuit (10)
Body ECU (8)
Taillight Does Not Light Up
Taillight Relay Circuit (11)
Body ECU (8)
Theft Deterrent Horn Or Horn Does Not Sound
Security Horn Circuit (12)
Horn Circuit (13)
Body ECU (8)
During Warning Condition, Cannot Be Canceled By Unlocking Door With A Key
Door Key Lock And Unlock Switch Circuit (Driver's) (14)
Door Key Lock And Unlock Switch Circuit (Passenger's) (15)
Body ECU (8)
During Warning Condition, Cannot Be Canceled By Unlocking Door With A Key (Transmitter)
Transmitter (16)
Body ECU (8)
During Warning Condition, Cannot Be Cancelled By Turning On With A Key
Ignition Switch (9)
Key Unlock Warning Switch Circuit (2)
Body ECU (8)
System Operated For More 60 Records
Body ECU (8)
(1) THEFT DETERRENT INDICATOR CIRCUIT 
(2) KEY UNLOCK WARNING SWITCH CIRCUIT 
(3) DOOR COURTESY SWITCH CIRCUIT 
(4) DOOR UNLOCK DETECTION SWITCH CIRCUIT
(5) DOOR UNLOCK DETECTION SWITCH CIRCUIT
(6) ENGINE HOOD COURTESY SWITCH CIRCUIT 
(7) BACK DOOR COURTESY SWITCH CIRCUIT
(8) HOW TO TROUBLESHOOT ECU CONTROLLED SYSTEMS
(9) IGNITION SWITCH AND KEY UNLOCK WARNING SWITCH
(10) INSPECT HEADLIGHT CONTROL RELAY CONTINUITY
(11) INSPECT TAILLIGHT CONTROL RELAY CONTINUITY
(12) THEFT DETERRENT HORN CIRCUIT 
(13) HORN SYSTEM
(14) DOOR KEY LOCK AND UNLOCK SWITCH CIRCUIT
(15) DOOR KEY LOCK AND UNLOCK SWITCH CIRCUIT
(16) INSPECT WIRELESS DOOR LOCK TRANSMITTER OPERATION