Lexus SC300 / Lexus SC400. Manual - part 657

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

.

–

ENGINE TROUBLESHOOTING

Diagnostic Code Chart

TR–17

DIAGNOSTIC CODE CHART (Cont’d)

TR–18

–

ENGINE TROUBLESHOOTING

Diagnostic Code Chart

Trouble Area

”CHECK” 

Engine Warning

Light *

Memory*



See Page

Trouble Area

Normal

Mode

Test

Mode

Memory

See Page

•

Open or short in air flow meter circuit.

•

Air flow meter

•

ECU

ON

N.A.



TR–88

•

ECU

ON

ON



TR–92

•

Open or short in throttle position sensor circuit.

•

Throttle position sensor

ON

ON



TR–94

Throttle  osition sensor

•

 ECU

•

No. 1 speed sensor

•

Combination meter

•

Open or short in No. 1 speed sensor circuit.

•

ECU

ON

ON



TR–98

•

Open or short in starter signal circuit.

•

Open or short in ignition switch or main relay circuit.

•

ECU

N.A.

OFF

X

TR–100

•

Open or short in sub–throttle position sensor circuit.

•

Sub–throttle position sensor

OFF

ON



TR–94

Sub throttle  osition sensor

•

ECU

•

Open or short in No. 1 knock sensor circuit.

•

O en or short in No. 1 knock sensor circuit.

•

No. 1 knock sensor (looseness)

ON

N.A.



No. 1 knock sensor (looseness)

•

ECU



•

 ECU

ON

N.A.

X

TR–102

•

 Open or short in No. 2 knock sensor circuit.

•

 O en or short in No. 2 knock sensor circuit.

•

 No. 2 knock sensor (looseness)

ON

N.A.



 No. 2 knock sensor (looseness)

•

 ECU



*1, 2: See page 

TR–20

.

–

ENGINE TROUBLESHOOTING

Diagnostic Code Chart

TR–19