Lexus RX300 (MCU15). Service manual — part 233

A10954

SPD

DI–164

–

DIAGNOSTICS

AUTOMATIC TRANSAXLE

LEXUS RX300 (RM785E)

INSPECTION PROCEDURE

HINT:
Read freeze frame data using hand–held tester or OBD scan tool. Because freeze frame records the engine
conditions when the malfunction is detected. When troubleshooting, it is useful for determining whether the
vehicle was running or stopped, the engine was warmed up or not, the air–fuel ratio was lean or rich, etc.
at the time of the malfunction.

1

Check operation of speedometer.

CHECK:
Drive the vehicle and check if the operation of the speedometer in the combination meter is normal.
HINT:
The vehicle speed sensor is operating normally if the speedometer display is normal.

NG

Check speedometer circuit.

OK

2

Check for short in harness and connector between terminal SPD of Engine &
ECT ECU connector and body ground.

PREPARATION:
Remove the glove compartment (See page BO–126).
CHECK:
Check the continuity between terminal SPD of the Engine &
ECT ECU connector and body ground.
OK:

No continuity (1 MΩ or higher)

NG

Repair or replace harness or connector.

OK

BE6653

A10955

ON

SPD

(+)

(–)

–

DIAGNOSTICS

AUTOMATIC TRANSAXLE

DI–165

LEXUS RX300 (RM785E)

3

Check voltage between terminal SPD of Engine & ECT ECU connector and body
ground.

PREPARATION:
(a)

Remove the glove compartment (See page BO–126).

(b)

Turn the ignition switch ON.

CHECK:
Measure the voltage between terminal SPD of the Engine &
ECT ECU connector and body ground.
OK:

Voltage: 0 – 5 V

NG

Check for open in harness and connector be-
tween connector (IJ1) and Engine & ECT ECU
(See page IN–32).

OK

4

Check for open in harness and connector between connector (IJ1) and combina-
tion meter (See page IN–32).

NG

Repair or replace harness or connector.

OK

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

Q08641

Automatic Transaxle

ATF Temperature
Sensor

Engine & ECT ECU

THO

E2

13

18

G–Y

BR

1

6

4 – 6V

E7

E7

E1

E1

O

O

DI–166

–

DIAGNOSTICS

AUTOMATIC TRANSAXLE

LEXUS RX300 (RM785E)

DTC

P0710

Transmission Fluid Temperature Sensor
Malfunction (ATF Temperature Sensor)

DTC

P0711

Transmission Fluid Temperature Sensor Cir-
cuit Range/Performance Problem

CIRCUIT DESCRIPTION

The ATF temperature sensor converts fluid temperature into a resistance value which is input into the Engine
& ECT ECU.

DTC No.

DTC Detecting Condition

Trouble Area

P0710

Either a) or b) is detected for 0.5 sec. or more.

(1 trip detection logic)

a) Temp. sensor resistance is less than 79 Ω

b) After the engine has been operating for 15 minutes or

more, the resistance at the temp. sensor is more than 156 kΩ

S Open or short in ATF temp. sensor

S ATF temp. sensor

S Engine & ECT ECU

P0711

Both (a) and (b) is detected.

(a) After 12 seconds of the engine start, the temp. of the atmo-

sphere and that of the engine coolant is more than –10

°C.

(b) After a normal driving for over 20 minutes and 6.2 miles (10

km), the ATF temp. is less than 10

°C.

S Open in ATF temp. sensor circuit

S ATF temp. sensor

S Engine & ECT ECU

WIRING DIAGRAM

DI1O2–08

D02967

1

6

–

DIAGNOSTICS

AUTOMATIC TRANSAXLE

DI–167

LEXUS RX300 (RM785E)

INSPECTION PROCEDURE

1

Check ATF temperature sensor.

PREPARATION:
(a)

Disconnect the solenoid wire connector.

(b)

Remove the oil pan.

(c)

Disconnect all solenoid valve connectors.

(d)

Remove transmission wire harness.

CHECK:
Measure resistance between terminals 1 and 7 of solenoid con-
nector at 25

°C (77 °F) and 110 °C (230 °F).

OK:

Resistance (Approx.):
25 °C (77 °F): 3.5 kΩ
110 °C (230 °F): 231 - 263 Ω

NG

Replace the ATF temperature sensor (transmis-
sion wire).

OK

2

Check harness and connector between ATF temperature sensor and Engine &
ECT ECU (See page IN–32).

NG

Repair or replace the harness or connector.

OK

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