Lexus RX300 (MCU15). Manual - part 235

D09086

Engine & ECT ECU

SL1+

SL1–

SL2+

SL2–

S4

E8

20

19

9

8

1

L–B

L–W

R–B

R–Y

5

10

4

9

8

W

B

Y

BR

R

SL2 Solenoid Vavle

S4 Solenoid Valve

SL1 Solenoid Valve

Automatic Transaxle

E8

E8

E8

E6

R–Y

R–W

To Cruise Control ECU

DI–172

–

DIAGNOSTICS

AUTOMATIC TRANSAXLE

LEXUS RX300   (RM785E)

WIRING DIAGRAM

D03339

D03338

D03340

D03440

SL1+

SL1–

Engine & ECT ECU

SL2+

SL2–

S4

Engine & ECT ECU

Engine & ECT ECU

–

DIAGNOSTICS

AUTOMATIC TRANSAXLE

DI–173

LEXUS RX300   (RM785E)

INSPECTION PROCEDURE

1

Measure resistance between terminals of Engine & ECT ECU.

PREPARATION:
Disconnect the connector from Engine & ECT ECU.
CHECK:
(a)

Measure resistance between terminal SL1+ and SL2– of
Engine & ECT ECU connector.

(b)

Measure resistance between terminal SL2+ and SL2– of
Engine & ECT ECU connector.

(c)

Measure resistance between terminal S4 of Engine &
ECT ECU connector and body ground.

OK:

Resistance:
SL1+ – SL1–: 5.3 ± 0.2 Ω
SL2+ – SL2–: 5.3 ± 0.2 Ω
S4 – Body ground: 13 ± 2 Ω

OK

Check and replace the Engine & ECT ECU (See
page IN–32).

NG

D03341
D03344
D03342

D03441

SL1–

SL1+

SL1+

Solenoid Connector

Solenoid Connector

Solenoid Connector

SL2–

SL2+

S4

S4

SL1–

SL2+

SL2–

DI–174

–

DIAGNOSTICS

AUTOMATIC TRANSAXLE

LEXUS RX300   (RM785E)

2

Check harness and connector between Engine & ECT ECU and automatic trans-
axle solenoid connector.

PREPARATION:
Disconnect the solenoid connector from the automatic trans-
axle.
CHECK:
(a)

Check the harness and connector between terminal
SL1+ or SL1– of Engine & ECT ECU and terminal SL1+
or SL1– of solenoid connector.

(b)

Check the harness and connector between terminal
SL2+ or SL2– of Engine & ECT ECU and terminal SL2+
or SL2– of solenoid connector.

(c)

Check the harness and connector between terminal S4
of Engine & ECT ECU and terminal S4 of solenoid con-
nector.

OK:

There is no open and no short circuit.

NG

Repair or replace the harness or connector.

OK

–

DIAGNOSTICS

AUTOMATIC TRANSAXLE

DI–175

LEXUS RX300   (RM785E)

3

Check SL1, SL2 or S4 solenoid valve (See page DI–168).

NG

Replace the solenoid valve.

OK

Repair or replace the solenoid wire.