Content .. 130 131 132 133 ..

Lexus ES300 (2002 year). Manual - part 132

ENGINE – 1MZ-FE ENGINE

EG-51

208EG35

From Air
Cleaner

Open

189EG37

6) DTC P0446 (Evaporative Emission Control System Vent Control Malfunction)

a. Canister Closed Valve

This stage checks the VSV (for canister closed valve) and vent (air inlet side) operation. When the vapor
pressure rises to a specified point, the ECM opens the canister closed valve. Pressure will increase rapid-
ly because of the air allowed into the system. No increase or an increase below specified rate of pressure
increase indicates a restriction on the air inlet side. If a malfunction is detected, the MIL illuminates
to inform the driver. Also, the DTC can be accessed through the use of a hand-held tester.
For details on the DTCs, refer to the 2002 ES300 Repair Manual (Pub. No. RM911U).

b. Pressure Switching Valve

The ECM closes the pressure switching valve. This action blocks air entire the tank side of the system.
The pressure rise is no longer as great. If there was no change in pressure, the ECM will conclude the
pressure switching valve did not close. If a malfunction is detected, the MIL illuminates to inform the
driver. Also, the DTC can be accessed through the use of a hand-held tester.
For details on the DTCs, refer to the 2002 ES300 Repair Manual (Pub. No. RM911U).

ENGINE – 1MZ-FE ENGINE

EG-52

Service Tip

The length of time to clear the DTC via the battery terminal has been changed from the previous 10 se-
conds to 1 minute.

13. Diagnosis

When the ECM detects a malfunction, the ECM makes a diagnosis and memorizes the failed section.
Furthermore, the MIL (Malfunction Indicator Lamp) in the combination meter illuminates or blinks to inform
the driver.
The ECM will also store the DTCs of the malfunctions.
The DTCs can be accessed the use of the hand-held tester.

– Changes (from ’01 ES300) –

The DTCs (Diagnostic Trouble Codes) listed below have been added or discontinued.

Added DTCs

DTC No.

Detection Item

P0156

Sensor Circuit Malfunction (Bank 2, Sensor 2)

P0161

Sensor Heater Circuit Malfunction (Bank 2, Sensor 2)

P0430

Catalyst System Efficiency Below Threshold (Bank 2)

P0605

Internal Control Module Read Only Memory (ROM) Error

P1120

Accelerator Pedal Position Sensor Circuit Malfunction

P1121

Accelerator Pedal Position Sensor Range / Performance Problem

P1125

Throttle Control Motor Circuit Malfunction

P1127

ETCS Actuator Power Source Circuit Malfunction

P1128

Throttle Control Motor Lock Malfunction

P1129

Electric Throttle Control System Malfunction

P1566

Input Signal Circuit Abnormal

P1633

ECM Malfunction (ETCS Circuit)

ENGINE – 1MZ-FE ENGINE

EG-53

14. Fail-Safe

General

When the ECM detects a malfunction, the ECM stops or controls the engine according to the data already
stored in the memory.

Fail-Safe Control List

: New

Location on Malfunction

Description Control

Mass Air Flow Meter

In case of a signal malfunction, the engine could operate poorly or
the catalyst could overheat if the engine continues to be controlled
with the signals from the sensors.
Therefore, the ECM effects control by using the values in the ECM
or stops the engine.

Accelerator Pedal Position Sensor

(For details, see page EG-54)

In case of a signal malfunction, the ECM calculates the accelerator
pedal opening angle that is limited by the dual system sensor value
and continues effecting throttle valve control. If both system
malfunction, the ECM considers that the accelerator pedal is fully
closed.

Throttle Position Sensor

(For details, see page EG-55)

In case of a signal malfunction, the ECM cuts off the current to the
throttle control motor. The throttle valve returns to the prescribed
opening by the force of the return spring. The ECM then adjusts the
engine output by controlling the fuel injection and ignition timing
in accordance with the accelerator pedal opening angle to enable
the vehicle to continue driving.

Engine Coolant Temp. Sensor

and

Intake Air Temp. Sensor

In case of a signal malfunction, the use of the values from the
sensors will make the air-fuel ratio become too rich or too lean,
which could causes the engine to stall or to run poorly during cold
operation. Therefore, the ECM fixes the air-fuel ratio to the
stoichiometric ratio and uses the constant values of 80

C engine

coolant temperature and 20

C intake air temperature to perform the

calculation.

Knock Sensor

In case of a malfunction in the knock sensor or in the knocking
signal system (open or short circuit), the engine could become
damaged if the timing is advanced despite the presence of
knocking. Therefore, if a malfunction is detected in the knock
sensor system, the ECM turns the timing retard correction of the
knock sensor into the maximum retard value.

Ignition Coil

(with Igniter)

In case of a malfunction in the ignition system, such as an open
circuit in the ignition coil, the catalyst could be become overheated
due to engine misfire. Therefore, if the (IGF) ignition signal is not
input twice or more in a row, the ECM determines that a
malfunction occurred in the ignition system and stops only the
injection of fuel into the cylinder with the malfunction.

ENGINE – 1MZ-FE ENGINE

EG-54

199EG45

ECM

Accelerator Pedal
Position Sensor

Main

Sub

Open

Main

Sub

Throttle
Position
Sensor

Throttle
Valve

Return
Spring

Throttle
Control
Motor

Accelerator Pedal

Throttle Body

199EG46

ECM

Accelerator Pedal
Position Sensor

Main

Sub

Main

Sub

Throttle
Position
Sensor

Throttle
Valve

Return
Spring

Throttle
Control
Motor

Accelerator Pedal

Throttle Body

Fail-Safe of Accelerator Pedal Position Sensor

The accelerator pedal position sensor comprises two (main, sub) sensor circuits. If a malfunction occurs

in either one of the sensor circuits, the ECM detects the abnormal signal voltage difference between these
two sensor circuit and switches to the limp mode. In the limp mode, the remaining circuit is used to calcu-
late the accelerator pedal opening, in order to operate the vehicle under limp mode control.

If both systems malfunction, the ECM detects the abnormal signal voltage between these two sensor cir-

cuits and regards that the opening angle of the accelerator pedal is fully opened and then continues the
throttle control. At this time, the vehicle can be driven within its idling range.

Content .. 130 131 132 133 ..