Lexus ES300 (2002 year). Manual - part 390

05-158

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DIAGNOSTICS

SFI SYSTEM (1MZ-FE)

311

2002 LEXUS ES300 REPAIR MANUAL   (RM911U)

4

INSPECT CAMSHAFT TIMING PULLEY

NG

REPLACE CAMSHAFT TIMING PULLEY

OK

CHECK AND REPLACE ECM

A61589

Battery

1

ALT

Driver 
Side J/B

Stop Light 
Switch

Passenger Side J/B

3A

G-W

G-W

Light Fallure Sensor 
and Stop Light

G-W

19

IK1

ECM

E7

W

FL MAIN

1

B-G

1

2

Engine 
Room 
R/B

2E

2G 13

1

STOP

7

4

15

2G

2M

2K

G-W

STP

3A

51

91

Driver Side J/B

SB

1

2

7

B-G

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DIAGNOSTICS

SFI SYSTEM (1MZ-FE)

05-159

312

2002 LEXUS ES300 REPAIR MANUAL   (RM911U)

DTC

P1520

STOP LIGHT SWITCH MALFUNCTION

CIRCUIT DESCRIPTION

This signal is used to detect when the brakes have been applied. The STP signal voltage is the same as
the voltage supplied to the stop lights.
The STP signal is used mainly to control the fuel cut-off engine speed (The fuel cut-off engine speed is re-
duced slightly when the vehicle is braking.).

DTC No.

DTC Detecting Condition

Trouble Area

P1520

Stop light switch does not turn off when repeating driving at 30
km or more 10 time or more after depressing brake (2 trip
detection logic)

Short in stop light switch signal circuit

Stop light switch

ECM

WIRING DIAGRAM

051MO-08

05-160

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DIAGNOSTICS

SFI SYSTEM (1MZ-FE)

313

2002 LEXUS ES300 REPAIR MANUAL   (RM911U)

INSPECTION PROCEDURE

HINT:
Read freeze frame data using hand-held tester or OBD II scan tool. Because freeze frame records the en-
gine conditions when the malfunction is detected. When troubleshooting, it is useful for determining whether
the vehicle was running or stopped, the engine was warmed up or not, the air-fuel ratio was lean or rich,
etc. at the time of the malfunction.

1

CHECK OPERATION OF STOP LIGHT

NG

REPAIR OR REPLACE STOP LIGHT SWITCH
CIRCUIT

OK

2

CHECK STP SIGNAL

(a)

Turn the ignition switch ON and push the hand-held tester main switch ON.

(b)

Read the STP signal on the hand-held tester.
Result:

Brake Pedal

STP Signal

Depressed

ON

Released

OFF

OK

CHECK FOR INTERMITTENT PROBLEMS

NG

3

CHECK HARNESS AND CONNECTOR(ECM  -  STOP LIGHT SWITCH)

NG

REPAIR OR REPLACE HARNESS AND
CONNECTOR

OK

CHECK AND REPLACE ECM

A61592

Engine Room J/B

E.F.I.

ECM

J11 J/C

Battery

FL MAIN

Engine Room R/B

1

B - G

A

EF

BR

BATT

2

2

1

1

B - G

B - Y

A

E1

9

1A

1B

E7

E8

B - Y

7

IF5

BR

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DIAGNOSTICS

SFI SYSTEM (1MZ-FE)

05-161

314

2002 LEXUS ES300 REPAIR MANUAL   (RM911U)

DTC

P1600

ECM BATT MALFUNCTION

CIRCUIT DESCRIPTION

Battery positive voltage is supplied to terminal BATT of the ECM even when the ignition switch is OFF for
use by the DTC memory and air-fuel ratio adaptive control value memory, etc.

DTC No.

DTC Detecting Condition

Trouble Area

P1600

Open in back up power source circuit

Open in back up power source circuit

ECM

HINT:
If DTC P1600 appear, the ECM does not store another DTC.

WIRING DIAGRAM

INSPECTION PROCEDURE

HINT:
Read freeze frame data using hand-held tester or OBD II scan tool. Because freeze frame records the en-
gine conditions when the malfunction is detected. When troubleshooting, it is useful for determining whether
the vehicle was running or stopped, the engine was warmed up or not, the air-fuel ratio was lean or rich,
etc. at the time of the malfunction.

051MP-09