Lexus SC300 / Lexus SC400. Manual - part 847

DIAGNOSTIC CODE CHART

HINT: Parameters listed in the chart may not be exactly same as your reading due to type of the instruments
or other factors.

*4: See page 

TR–21

.

TR–14

–

ENGINE TROUBLESHOOTING

Diagnostic Code Chart

If a malfunction code is displayed during the diagnostic code check in test mode, check the circuit for that code
listed in the table below (Proceed to the page given for that circuit).

Tro ble Area

”CHECK” Engine

Warning Light *

Memory*



See Page

Trouble Area

Normal

Mode

Test

Mode

–––––––––––––

–––

–––

–––––

–––––

•

Open or short in engine speed sensor, No. 1, No. 2
cam position sensor circuit.

•

Engine speed sensor

•

No. 1, No. 2 cam position sensor

•

Starter

•

ECU

ON

N.A.



TR–48

•

 Open or short in engine speed sensor circuit.

•

 O en or short in engine s eed sensor circuit.

•

 Engine speed sensor

ON

N.A.

 Engine s eed sensor

•

 ECU

ON

N.A.

•

 Open or short in engine speed sensor circuit.

g

•

 Mechanical system malfunction (skipping teeth of
ti i

timing

•

belt belt stretched)

N.A.

ON



TR 52

•

belt, belt stretched)

•

Engine speed sensor



TR–52

•

 Engine s eed sensor

•

 ECU

•

 Mechanical system malfunction (skipping teeth of

•

 Mechanical system malfunction (ski

ing teeth of

•

timing belt, belt stretched)

ON

N A

•

timing belt, belt stretched)

•

 No. 1, No. 2 cam position sensor

ON

N.A.

 No. 1, No. 2 cam  osition sensor

•

 ECU

•

 Open or short in IGF1 circuit from igniter No.
1–ECU.

•

 Igniter No. 1

•

 ECU

ON

N.A.



TR–54

•

 Open or short in IGF2 circuit from igniter No.
2–ECU.

•

 Igniter No. 2

•

 ECU

ON

N.A.



TR–54

•

 ECU

ON

N.A.

X

TR–61

•

 Open or short in heater circuit of main oxygen sen-
sor.

•

Main oxygen sensor heater

ON

N.A.

•

 Main oxygen sensor heater

•

 ECU



TR–62

•

 Main oxygen sensor circuit

•

Main oxygen sensor

ON

ON

•

 Main oxygen sensor

*1, 2: See page 

TR–20

.

–

ENGINE TROUBLESHOOTING

Diagnostic Code Chart

TR–15

DIAGNOSTIC CODE CHART (Cont’d)

* 3, 4: See page 

TR–20

, 21.

TR–16

–

ENGINE TROUBLESHOOTING

Diagnostic Code Chart

”CHECK” Engine

Tro ble Area

CHECK  Engine

Warning Light *

Memory*



See Page

Trouble Area

Normal

Mode

Test

Mode

Memory*



See Page

•

 Open or short in water temp. sensor circuit.

•

 Water temp. sensor

•

 ECU

ON

ON



TR–68

•

Open or short in intake air temp sensor circuit

OFF

•

 Open or short in intake air temp. sensor circuit.

•

Intake air temp sensor

OFF

ON



TR 72

•

 Intake air temp. sensor

ECU

ON*3

ON



TR–72

•

 ECU

ON*3

•

 Open or short in main oxygen sensor circuit.

•

 O en or short in main oxygen sensor circuit.

•

 Main oxygen sensor

 Main oxygen sensor

•

 Ignition system

g

y

•

 Water temp. sensor

•

 Open or short in injector circuit.

•

 O en or short in injector circuit.

•

 Fuel line pressure (injector blockage)

•

 Fuel line  ressure (injector blockage)

•

 Air flow meter (air intake)

ON

ON



TR–74

 Air flow meter (air intake)

•

 Engine ground bolt loose



g

g

•

 Foreign object caught in valve

•

 Fuel line pressure (injector leak, blockage)

•

 Fuel line  ressure (injector leak, blockage)

•

 Mechanical system malfunction

 Mechanical system malfunction

•

(skipping teeth of timing belt)

(

g

g

)

•

 Ignition system

•

 Open or short in heater circuit of sub–oxygen sen-
sor.

•

Sub–oxygen sensor heater

ON

N.A.

•

 Sub–oxygen sensor heater.

•

 ECU



TR–82

•

 Open or short in sub–oxygen sensor circuit.



TR 82

•

 O en or short in sub oxygen sensor circuit.

•

 Sub–oxygen sensor

ON

ON

 Sub oxygen sensor

•

 ECU

•

 Same as (1) of Code No. 21

ON

N.A.



TR 62

•

 Same as (2) of Code No. 21

ON

ON



TR–62

•

 Same as (1) of Code No. 27

ON

N.A.



TR 82

•

 Same as (2) of Code No. 27

ON

ON



TR–82

*1, 2, 3: See page 

TR–20

.

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ENGINE TROUBLESHOOTING

Diagnostic Code Chart

TR–17