Lexus RX300 (MCU15). Service manual — part 211

A10233

BE6653

A11814

ON

EVP1 (+)

DI–76

–

DIAGNOSTICS

ENGINE

LEXUS RX300 (RM785E)

Check and replace engine ECU (See page
IN–32).

OBD scan tool (excluding hand–held tester):

1

Check VSV for EVAP (See page FI–59).

NG

Replace VSV for EVAP.

OK

2

Check voltage between terminal EVP1 of engine ECU connector and body
ground.

PREPARATION:
(a)

Remove the engine ECU with connector still connected
(See page FI–70).

(b)

Turn the ignition switch ON.

CHECK:
Measure the voltage between terminal EVP1 of the engine
ECU connector and body ground.
OK:

Voltage: 9 – 14 V

NG

Check for open and short in harness and con-
nector between EFI main relay and engine ECU
(See page IN–32).

OK

Check and replace engine ECU (See page
IN–32).

A00223

Vehicle Speed
Sensor

Combination
Meter

Engine ECU

Transaxle

4–Pulse

4–Pulse

Vehicle Speed Sensor

Q00515 Q00514

A14516

C10
Combination Meter ECU

Engine ECU

8

E10

3K

3E

SPD

22

V–W

J/B No. 3

IJ1

12

2

10

V–W

V–W

–

DIAGNOSTICS

ENGINE

DI–77

LEXUS RX300 (RM785E)

DTC

P0500

Vehicle Speed Sensor Malfunction

CIRCUIT DESCRIPTION

The vehicle speed sensor outputs a 4–pulse signal for every revolution of the rotor shaft, which is rotated
by the transmission output shaft via the driven gear. After this signal is converted into a more precise rectan-
gular waveform by the waveform shaping circuit inside the combination meter, it is then transmitted to the
engine ECU. The engine ECU determines the vehicle speed based on the frequency of these pulse signals.

DTC No.

DTC Detecting Condition

Trouble Area

P0500

No vehicle speed sensor signal to engine ECU under condi-

tions (a) and (b): (2 trip detection logic)

(a) Neutral start switch is OFF

(b) Vehicle is being driven

S Open or short in vehicle speed sensor circuit

S Vehicle speed sensor

S Combination meter

S Engine ECU

WIRING DIAGRAM

DI4ED–13

A02030

E14 Connector

SPD

DI–78

–

DIAGNOSTICS

ENGINE

LEXUS RX300 (RM785E)

INSPECTION PROCEDURE

HINT:
Read freeze frame data using hand–held tester. Because freeze frame records the engine conditions when
the malfunction is detected, when troubleshooting it is useful for determining whether the vehicle was run-
ning 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 ECU
and body ground.

PREPARATION:
(a)

Remove the glove compartment (See page FI–70).

(b)

Disconnect the E14 connector of engine ECU.

CHECK:
Check continuity between terminal SPD of engine ECU con-
nector and body ground.
OK:

No continuity (1 MΩ or higher)

NG

Repair or replace harness or connector.

OK

A02029

ON

E14 Connector

SPD (+)

–

DIAGNOSTICS

ENGINE

DI–79

LEXUS RX300 (RM785E)

3

Check voltage between terminal SPD of engine ECU connector and body ground.

PREPARATION:
Turn the ignition switch ON.
CHECK:
Measure voltage between terminal SPD of the engine ECU
connector and body ground.
OK:

Voltage: 9 – 14 V

NG

Check for open in harness and connector be-
tween junction connector and engine ECU (See
page IN–32).

OK

4

Check for open in harness and connector between junction connector and com-
bination meter (See page IN–32).

NG

Repair or replace harness or connector.

OK

Check and replace engine ECU (See page
IN–32).