Lexus SC300 / Lexus SC400. Manual - part 659

YES

NO

NO

YES

YES

NO

OK

NG

BASIC INSPECTION

When the normal code is displayed in the diagnostic code check, troubleshooting should be performed in the
order for all possible circuits to be considered as the causes of the problems.
In many cases, by carrying out the basic engine check shown in the following flow chart, the location causing
the problem can be found quickly and efficiently. Therefore, use of this check is essential in engine troubleshoot-
ing.

1

Is battery voltage 11 V or more when engine is stopped?

Charge or replace battery.

2

Is engine cracnked?

Proceed to matrix to matrix chart of problem
symptoms on page 

TR–35

.

3

Does engine start?

Go to step [7]

4

Check air filter

C

Hint

P

Remove air filter

Visially check that the air cleaner element is not exces-
sively damaged or oily.

If necessary, clean element with compressed air.  First
blow from inside thoroughly, then blow off outside of ele-
ment.

Repair or replace

Go to Step [5].

TR–24

–

ENGINE TROUBLESHOOTING

Basic Inspection

OK

NG

OK

NG

5

Check idle speed.

C

OK

P

(1) Warm up engine at normal operating temperature.

(2) Switched off all accessories.

(3) Switched off air conditioner.

(4) Shift transmission into “N” range.

(5) Connect tachometer test probe to terminal IG 

 of

check connector, and set the tachometer to the
4–cylinder range.

Check idle speed.

Idle speed: 650 ~ 750 rpm

Caution:

NEVER allow tachometer test probe to touch
ground as it could result in damage to igniter
and/or coil.

As some tachometers are not compatible with
this ignition system, we recommended that you
confirm compatibility of your unit before use.

Proceed to matrix chart of problem symptoms on page

TR–35

.

6

Check ignition timing.

C

OK

P

(1) Warm up engine at normal operating temperture.

(2) Shift transmission into “N” range.

(3) Keep the engine speed at idle.

(4) Using SST, connect terminals TE1 and E1 of check

connector.

SST 09843–18020

(5) Using a timing light. connect the tester to No. 6

high–tension cord.

Check ignition timing.

Ignition Timing: 8–12



 BTDC at idle

Proceed to page 

IG–28

 and continue to troubleshoot.

Proceed to matix chart of problem symptoms on

page 

TR–35

.

–

ENGINE TROUBLESHOOTING

Basic Inspection

TR–25

OK

NG

OK

NG

7

Check fuel pressure.

C

P

(1) Be sure that fuel is enough in tank.

(2) Turn ignition switch on.

(3) Using SST, connect terminals FP and + B of check

connector.

SST 09843–18020

Check that pulsation damper screw rises up when termi-
nals are connected.

Caution:

Never make a mistake with the terminal connection
position as this will cause a malfunction.

Proceed to page 

FI–18

 and continue to troubleshoot.

8

Check for spark.

C

Hint

Disconnect the high–tension cord from the distributor
and, hold the end about 12.5 mm (1/2”) from the ground,
see if spark occurs while the engine is being cranked.

To prevent excessive fuel injected from the injectors dur-
ing this test, Don’t crank the engine for more than 1 – 2
seconds at a time.

Proceed to the page 

IG–6

 and continue to troubleshoot.

Proceed to matix chart of problem systems on

page 

TR–35

.

TR–26

–

ENGINE TROUBLESHOOTING

Basic Inspection

PARTS LOCATION

–

ENGINE TROUBLESHOOTING

Parts location

TR–27