Lexus SC300 / Lexus SC400. Manual - part 61

11.  DIAGNOSTIC CODE CHECK

After repeating ignition switch ON–OFF operation (ON: wait 20 secs., OFF: wait 20 secs.) 5 times, check
the diagnostic codes. If only code 41 is displayed, proceed to step [ 12 ]. If a code other than code 41 is
displayed, return to step [ 7 ] and troubleshoot the displayed malfunction code.
NOTICE: When connecting the battery after clearing the malfunction code, always do it with the ignition
switch in LOCK position. When the battery has been reconnected, turn the ignition switch to ACC or ON
position after at least 2 seconds have elapsed.
If the battery is reconnected with the ignition switch in ACC or ON position, or the ignition switch is turned
ACC or ON within 2 seconds of connecting the battery, it is possible that the diagnosis system will not oper-
ate normally.

12.  CLEARING OF MALFUNCTION CODE 41 STORED IN MEMORY

Clear malfunction code 41 stored in memory. This operation is not necessary only in case that the power
source voltage returns to normal.

13. CONFIRMATION 

TEST

Check the warning light again and confirm that all the malfunctions have been repaired. If the warning light
indicates an abnormality, repeat the operation again from step [ 2 ]. If code 41 is output at step [ 3 ], skip
steps [ 4 ] and [ 5 ] and proceed to step [ 7 ].

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 AIRBAG   –   Troubleshooting

Customer Problem Analysis

Diagnostic Code Check and Recording

P. 

AB–30

P. 

AB–29

Warning Light Check

P. 

AB–30

Diagnostic Code Check and Recording

P. 

AB–30

Clearing of Malfunction Code (Except Code 41)

P. 

AB–32

Diagnostic Code Chart

P. 

AB–34

Circuit Inspection

P. 

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Identification of Problem

Repair

Vehicle Brought to Workshop

Symptom Simulation

P. 

IN–20

Clearing of Malfunction Code (Except Code 41)

P. 

AB–32

Diagnostic Code Check

P. 

AB–30

Clearing of Malfunction Code 41 Stored in Memory

P. 

AB–32

Confirmation Test

END

Only Code 41 Output

Output Other Than Code 41

Output Other Than Code 41

Only Code 41

Output

Output Other Than

Code 41

Only Code 41

Output

Does Not Light Up

Normal Code

Malfunction Code

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 AIRBAG   –   Troubleshooting

Customer Problem Analysis Check Sheet

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 AIRBAG System Check Sheet

Registration No.

Customer’s Name

Registration Year

/              /

Frame No.

Date Vehicle
Brought In

/              /

Odometer Reading

Km
Miles

Date of Problem Occurrence

                           /              /

Weather



Fine



Cloudy



Rainy



Snowy



Various/Other

Conditions

Outdoor
Temperature



Hot



Warm



Cool



Cold (Approx.      

C (    

F))

Conditions
at Time
of Problem
Occurrence

Vehicle
Operation



Starting



Idling



Driving



Constant speed



Acceleration



Deceleration



Other]

[

Condition
of road

Details of Problem

Vehicle Inspection,
Repair History Prior
to Occurrence of
Malfunction
(Including Airbag
System)

(Diagnosis System Inspection)

Airbag Warning

1st Time



Remain On



Sometimes Lights Up



Does Not Light Up

Airbag Warning
Light Inspection

2nd Time



Remain On



Sometimes Lights Up



Does Not Light Up

Diagnostic Code

1st Time



Normal Code



Malfunction Code [Code.

]

Diagnostic Code
Inspection

2nd Time



Normal Code



Malfunction Code [Code.

]

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 AIRBAG   –   Troubleshooting

Inspector’s
Name:

Diagnosis Inspection

AIRBAG WARNING LIGHT CHECK

(a)  Turn the ignition switch to ACC or ON and check that the

airbag warning light lights up.

(b)  Check that the airbag warning light goes out after

approx. 6 seconds.

HINT:

•

When the ignition switch is at ACC or ON and the airbag
warning light remains on, the center airbag sensor
assembly has detected a malfunction code.

•

If, after approx. 6 seconds have elapsed, the airbag
warning light sometimes lights up or the airbag warning
light lights up even when the ignition switch is OFF, a
short in the airbag warning light circuit can be
considered likely. Proceed to Airbag warning light
system (always lit up) on page 

AB–84

.

DIAGNOSTIC CODE CHECK

1. 

OUTPUT DIAGNOSTIC CODE
(a)  Turn the ignition switch to ACC or ON position and wait

approx. 20 seconds.

(b)  Using SST, connect terminals Tc and E

1

 of the TDCL.

SST 09843–18020
NOTICE: Never make a mistake with the terminal connec-
tion position as this will cause a malfunction.

2. 

READ DIAGNOSTIC CODE
Read the diagnostic code as indicated by the number of
times the airbag warning light blinks.

•

Normal code indication

The light will blink 2 times per second.

•

Malfunction code indication
In the event of a malfunction, the light will blink. The first
number of the code No. will equal the first digit of a
2–digit diagnostic code, and after a 1.5 second pause,
the 2nd number of the code No. will equal the 2nd digit.
If there are two or more codes, there will be a 2.5 second
pause between each.

After all the codes have been output, there will be a 4.0 se-
cond pause and they will all be repeated.
HINT:

•

In the event of a number of trouble codes, indication will
begin from the smaller numbered code to the larger.

•

If a diagnostic code is not output or is continuously
output, proceed to the TC terminal circuit inspection on
page 

AB–86

.

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 AIRBAG   –   Troubleshooting