Lexus SC300 / Lexus SC400. Manual - part 791

SRS WARNING LIGHT CHECK

DIAGNOSIS INSPECTION

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

warning light lights up.

(b)  Check that the SRS warning light goes out after approx. 6

seconds.
HINT:

•

When the ignition switch is at ACC or ON and the SRS
warning light remains on, the TROUBLESHOOTING
has detected a malfunction code.

•

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

RS–119

.

DIAGNOSTIC TROUBLE CODE CHECK

Using diagnosis check wire:

1. 

OUTPUT DIAGNOSTIC TROUBLE CODE

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

approx. 20 seconds.

(b)  Using SST, connect terminals Tc and E of the DLC2.

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

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SUPPLEMENTAL RESTRAINT SYSTEM

TROUBLESHOOTING

RS–59

2. 

READ DIAGNOSTIC TROUBLE CODE
Read the 2–digit diagnostic trouble code as indicated by the
number of times the SRS warning light blinks. As an example,
the blinking patterns; normal, 11 and 31 are as shown on the
illustration.

•

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 number
represented by the first blink code output indicates the first
digit of a 2–digit diagnostic trouble code. After a 1.5 second
pause, the second blink code will indicate the second 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 it does not output a diagnostic trouble code or output
a diagnostic trouble code without terminal connection,
proceed to the Tc terminal circuit inspection on page

RS–121

.

Using LEXUS hand–held tester:

(a)  Hook up the LEXUS hand–held tester to the DLC1 or DLC2.
(b)  Read the diagnostic trouble codes by following the prompts

on the tester screen.
HINT: Please refer to the LEXUS hand–held tester operator’s
manual for further details.

RS–60

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SUPPLEMENTAL RESTRAINT SYSTEM

TROUBLESHOOTING

DIAGNOSTIC TROUBLE CODES

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SUPPLEMENTAL RESTRAINT SYSTEM

TROUBLESHOOTING

RS–61

HINT:

When the SRS warning light remains lit up and the diagnostic trouble code in the normal code, this means a

source voltage drop.
This malfunction is not stored in memory by the center airbag sensor assembly and if the power source voltage
returns to normal, after approx. 10 seconds the SRS warning light will automatically go out.

Code 22 in recorded when a malfunction occurs in the SRS warning light system. If an open malfunction occurs

in the SRS warning light system, the SRS warning light does not light up. so that until the malfunction is repaired,
the diagnostic trouble codes (including code 22) cannot be confirmed.

When 2 or more codes are indicated, the lowest numbered code will appear first.

If a code not listed on the chart is displayed, then the center airbag sensor assembly is faulty.

RS–62

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SUPPLEMENTAL RESTRAINT SYSTEM

TROUBLESHOOTING