Lexus SC300 / Lexus SC400. Manual — part 90

NG

OK

NG

OK

OK

NG

INSPECTION PROCEDURE

1

Check voltage between terminal OD1of 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.

Measure voltage between terminal OD1 of ECM con-
nector and body ground.

Voltage:

4 – 6 V

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

2

Check voltage between terminal OD of cruise control ECU harness side connector and body
ground.

C

OK

P

1.

Disconnect cruise control ECU connector.

2.

Turn ignition switch ON.

Measure voltage between terminal OD of cruise control
ECU harness side connector and body ground.

Voltage:

4 – 6– V

Check and replace cruise control ECU.

3

Check harness or connector between cruise control ECU and ECM (See page IN–33).

Repair or replace harness or connector.

Check and replace ECM.

–

A304E (1UZ–FE) AUTOMATIC TRANSMISSION

TROUBLESHOOTING

AT–117

AT–66

IN–33

WIRING DIAGRAM

TE

1

Terminal Circuit

CIRCUIT DESCRIPTION

ECM displays diagnostic trouble codes using the O/D OFF indicator light when terminals TE and E of the
DLC2 or DLC1 are connected.

DIAGNOSTIC CHART

DIAGNOSTIC CHART

AT–118

–

A304E (1UZ–FE) AUTOMATIC TRANSMISSION

TROUBLESHOOTING

OK

NG

OK

NG

INSPECTION PROCEDURE

1

Check voltage between terminal TE

1

and E

1

of DLC2 or DLC1.

C

OK

Measure voltage between terminals TE

1

and E

1

of

DLC2 or DLC1.

Voltage:

4 – 6 V

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

2

Check harness and connector between ECM and DLC2, DLC1 and body ground (See page
IN–33).

Repair or replace harness or connector.

Check and replace ECM.

–

A304E (1UZ–FE) AUTOMATIC TRANSMISSION

TROUBLESHOOTING

AT–119

IN–33

WIRING DIAGRAM

T

T

Terminal Circuit

CIRCUIT DESCRIPTION

Checks of ECM input and output signals related to the throttle position sensor brakes, shift position and
other circuits can be performed by measuring the voltages at terminal T

T

of the DLC1.

DIAGNOSTIC CHART

DIAGNOSTIC CHART

AT–120

–

A304E (1UZ–FE) AUTOMATIC TRANSMISSION

TROUBLESHOOTING