Lexus RX300 (MCU15). Service manual — part 305

DI616–05

DI–452

–

DIAGNOSTICS

THEFT DETERRENT SYSTEM

LEXUS RX300 (RM785E)

PROBLEM SYMPTOMS TABLE

Proceed to the reference page shown in the matrix chart below for each malfunction symptom and trouble-
shoot for each circuit.
HINT:
Troubleshooting of the theft deterrent system is based on the premise that the door lock control system is
operating normally. Accordingly, before troubleshooting the theft deterrent system, first make certain that
the door lock control system is operating normally.

Symptom

Suspect Area

See page

The theft deterrent system cannot be set

4. Indicator light circuit

5. ECU power source circuit

6. Key unlock warning switch circuit

7. Back door key lock and unlock switch circuit

8. Back door courtesy switch circuit

9. Door key lock and unlock switch circuit

10.Door courtesy switch circuit

11.Door unlock detection switch circuit

12.Engine hood courtesy switch circuit

DI–453

DI–455

DI–461

DI–463

DI–592

DI–610

DI–612

DI–608

DI–470

The indicator light does not blink when system is set.

Indicator light circuit

DI–453

When the system is set

(The system does not operate when the rear door is unlocked).

Door unlock detection switch circuit

DI–612

When the system is set

(The system does not operate when the back door is opened by a

method other than the key).

Back door courtesy switch circuit

DI–592

When the system is set

(The system does not operate when the engine hood is opened).

Engine hood courtesy switch circuit

DI–470

When the system is set

(The system does not operate when after 30 seconds put your

hand through the window and shake it near the sensor).

Radar sensor circuit

DI–468

While the system is in warning operation

(Horns do not sound).

Horn relay circuit

DI–459

While the system is in warning operation

(Siren does not sound).

Self power siren circuit

DI–465

While the system is in warning operation

(When the siren does not sound or stops soon after it starts).

Self power siren battery

BE–109

While the system is in warning operation

(Hazard lights do not flash).

Hazard switch circuit

DI–578

While the system is in warning operation

(The door lock is not locked).

Door unlock detection switch circuit

DI–608

System is still set even when a rear door is open

Door courtesy switch circuit

DI–612

Even when the system is not set

(Horns sound).

Horn relay circuit

DI–459

Even when the system is not set

(Siren sounds).

Self power siren circuit

DI–465

Even when the system is not set

(when the siren does not sound or stops soon after it starts).

Self power siren battery

BE–109

Even when the system is not set

(Hazard lights do not flash).

Hazard switch circuit

DI–578

DI617–04

I19241

Theft Deterrent ECU

IND

T5

12

L

IE1

18

MPX–LP

13

(*1)

I17
Instrument Control Panel

IH

L

L

(*2)

12

3

1

C12
Combination Meter ECU

T6
Theft Deterrent
Indicator Light

*1: Europe
*2: RHD except Europe

Y–B

W–B

3F

21

22

W–B (*2)

10

J/B No. 3

10

3E

9

3H

W–B

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DIAGNOSTICS

THEFT DETERRENT SYSTEM

DI–453

LEXUS RX300 (RM785E)

CIRCUIT INSPECTION

Indicator Light Circuit

CIRCUIT DESCRIPTION

When the theft deterrent system is preparing to set, this circuit lights up the indicator light. When the system
has been set, it continually turns the indicator light ON for 1 second and turns it OFF for 1 second, thus blink-
ing the indicator light.

WIRING DIAGRAM

DI–454

–

DIAGNOSTICS

THEFT DETERRENT SYSTEM

LEXUS RX300 (RM785E)

INSPECTION PROCEDURE

HINT:
In case of using the hand–held tester, start the inspection from step 1 and in case of not using the hand–held
tester, start from step 2.

1

Check theft deterrent indicator using hand–held tester.

PREPARATION:
(a)

Connect the hand–held tester to the DLC 3.

(b)

Connect terminals Tc and E1 of DLC1.

CHECK:
Check that the theft deterrent in indicator can light in an ACTIVE TEST.

OK

Proceed to next circuit inspection shown in
problem symptoms table (See page DI–452).

NG

2

Check indicator light (See page BE–109).

NG

Replace the bulb or meter wire harness.

OK

3

Check harness and connector between theft deterrent ECU and indicator light,
indicator light and body ground (See page IN–32).

NG

Repair or replace harness or connector.

OK

Check and replace theft deterrent ECU.*1

*1: When there is a malfunction that the theft deterrent system cannot be set, proceed to the next numbered
circuit inspection shown in problem symptom table (See page DI–452).

I19242

Engine Room J/B

Instrument Panel J/B

Theft Deterrent ECU

*1: LHD
*2: RHD

10

T4

+B1

W–R

W–B

IF

A

J7
J/C

ECU–B

22

T4

E

W–B

A

1H

6

W–L (*2)

G–B (*1)

1G

10

4

2A

Short Pin

W

Battery

1

FL Block

1

2I

3

W

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DIAGNOSTICS

THEFT DETERRENT SYSTEM

DI–455

LEXUS RX300 (RM785E)

ECU Power Source Circuit

CIRCUIT DESCRIPTION

This circuit provides power to operate the theft deterrent ECU.

WIRING DIAGRAM

DI84T–01