Lexus SC300 / Lexus SC400. Manual — part 89

O/D OFF indicator light does not light up.

AT–66

BE

IN–33

IN–33

O/D OFF indicator light blinks

Perform diagnostic trouble code check (See page AT–38).

–

A304E (1UZ–FE) AUTOMATIC TRANSMISSION

TROUBLESHOOTING

AT–113

OK

NG

OK

NG

OK

NG

INSPECTION PROCEDURE

1

Check operation of O/D Main Switch

C

OK

Hint

C

OK

1.

Turn ignition switch ON.

2.

Check “O/D OFF” light when O/D main switch is
pushed in to ON.

“O/D OFF” light goes off.

3.

Check “O/D OFF” light when O/D main switch is
pushed again, to OFF.

“O/D OFF” light lights up.

If the “O/D OFF” lights blinks when the O/D main switch
is pushed in to ON, a malfunction is occurring in the sys-
tem.
Check the diagnostic trouble code.

Go to step

.

2

Check voltage between terminal OD2 of ECM connector and body ground.

C

OK

P

1.

Connect the check harness A to the ECM (See EG
section).

2.

Turn ignition switch ON.

Check voltage between terminal OD2 of ECM and body
ground

Proceed to next circuit inspection shown on matrix chart
(See page AT–66).

3

Check harness and connector between O/D off indicator light and ECM (See page IN–33).

Repair or replace harness or connector.

Check and replace ECM.

AT–114

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A304E (1UZ–FE) AUTOMATIC TRANSMISSION

TROUBLESHOOTING

OK

NG

4

Check O/D Main Switch.

C

OK

1.

Disconnect O/D main switch connector. (See BO
section).

2.

Measure resistance between terminals 2 and 4 of
O/D main switch connector.

Replace O/D Main Switch.

Check and replace combination meter. (See com-
bination meter troubleshooting on BE section).

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A304E (1UZ–FE) AUTOMATIC TRANSMISSION

TROUBLESHOOTING

AT–115

AT–66

IN–33

WIRING DIAGRAM

O/D Cancel Signal Circuit

CIRCUIT DESCRIPTION

While driving with cruise control activated, in order to minimize gear shifting and provide smooth cruising
when driving uphill, overdrive may be prohibited temporarily in some conditions.The cruise control ECU
sends O/D cut signals to the ECM as necessary and the ECM cancels overdrive shifting until these signals
are discontinued.(For details, see the cruise control system, on BE section).

DIAGNOSTIC CHART

DIAGNOSTIC CHART

AT–116

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A304E (1UZ–FE) AUTOMATIC TRANSMISSION

TROUBLESHOOTING