Lexus ES300 (2002 year). Manual — part 362

05-68

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DIAGNOSTICS

SFI SYSTEM (1MZ-FE)

221

2002 LEXUS ES300 REPAIR MANUAL (RM911U)

7

CHECK FUEL PRESSURE (See page

11-4

)

NG

GO TO FUEL SYSTEM

OK

8

CHECK EXHAUST GAS LEAK

NG

REPAIR OR REPLACE EXHAUST GAS
LEAKAGE POINT

OK

9

READ VALUE OF OBD II SCAN TOOL OR HAND-HELD TESTER(AIR FUEL RATIO
SENSOR)

(a)

Connect the OBD II scan tool or hand-held tester to the DLC3.

(b)

Warm up the A/F sensor with the engine speed at 2,500 rpm for approx. 90 sec.

(c)

Read the voltage value of the A/F sensor on the screen of OBD II scan tool or hand-held tester when
you perform all the following conditions.

HINT:
The voltage of the AFR+ or AFL+ terminal of the ECM is 3.3 fixed the AFR- or AFL- terminal is 3.0 V fixed.
Therefore, it is impossible to check the A/F sensor output voltage at the terminals (AFR+, AFL+/AFR-, AFL-)
of the ECM.

Air fuel ration sensor output voltage:

Condition

A/F Sensor Voltage value

Engine idling

Not remains at 3 30 V (0 660 V*)

Engine racing

Not remains at 3.30 V (0.660 V*)

Not remains at 3 8 V (0 76 V*) or more

Driving at engine speed 1,500 rpm or more and vehicle
speed 40 km/h (25 mph) or more, and operate throttle valve
open and close

Not remains at 3.8 V (0.76 V*) or more

Not remains at 2.8 V (0.56 V*) or less

*: When you use OBD II scan tool (excluding hand-held tester)

HINT:

During fuel enrichment, there is a case that the output voltage of the A/F sensor is below 2.8 V (0.56
V*), it is normal.

During fuel cut, there is a case that the output voltage of the A/F sensor is above 3.8 V (0.76 V*), it
is normal.

If the output voltage of the A/F sensor remains at 3.30 V (0.660 V*) even after performing all the above
conditions, the A/F sensor circuit may be open.

If the output voltage of the A/F sensor remains at 3.8 V (0.76 V*) or more, or 2.8 V (0.56 V*) or less
even after performing all the above conditions, the A/F sensor circuit may be short.

*: When you use the OBD II scan tool (excluding hand-held tester).

OK

Go to step 11

NG

HAFL(LH)

+B

HAFR(RH)

AFL+(LH)
AFR+(RH)

AFL-(LH)
AFR-(RH)

A52189

A55005

E9

AFL+

AFL-

AFR-

AFR+

HAFL

HAFR

E2

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DIAGNOSTICS

SFI SYSTEM (1MZ-FE)

05-69

222

2002 LEXUS ES300 REPAIR MANUAL (RM911U)

10

CHECK HARNESS AND CONNECTOR(ECM - A/F SENSOR)

(a)

Disconnect the air fuel ratio sensor connector.

(b)

Disconnect the ECM E9 connector.

(c)

Check for open between the terminals HAFL of the ECM
connector and HAFL of the air fuel ratio sensor connector.
Resistance: 1

Ω

or less

(d)

Check for open between the terminals AFL+ of the ECM
connector and AFL+ of the air fuel ratio sensor connector.
Resistance: 1

Ω

or less

(e)

Check for open between the terminals AFL- of the ECM
connector and AFL- of the air fuel ratio sensor connector.
Resistance: 1

Ω

or less

(f)

Check for open between the terminals HAFR of the ECM
connector and HAFR of the air fuel ratio sensor connec-
tor.
Resistance: 1

Ω

or less

(g)

Check for open between the terminals AFR+ of the ECM
connector and AFR+ of the air fuel ratio sensor connector.
Resistance: 1

Ω

or less

(h)

Check for open between the terminals AFR- of the ECM
connector and AFR- of the air fuel ratio sensor connector.
Resistance: 1

Ω

or less

(i)

Check for short between the terminals HAFL, HAFR,
AFL+, AFR+, AFL-, AFR- and E2 of the ECM connector.
Resistance: 1 M

Ω

or more

NG

REPAIR OR REPLACE HARNESS AND
CONNECTOR

OK

REPLACE AIR FUEL RATIO SENSOR

11

PERFORM CONFIRMATION DRIVING PATTERN (See page

05-52

)

GO

12

READ OUTPUT DTC(DTC P0171,P0172,P0174 AND P0175 OUTPUT AGAIN)

YES

CHECK AND REPLACE ECM

NO

13

CONFIRM VEHICLE RUNS OUT OF FUEL IN THE PAST

NO

CHECK FOR INTERMITTENT PROBLEMS

YES

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DIAGNOSTICS

SFI SYSTEM (1MZ-FE)

223

2002 LEXUS ES300 REPAIR MANUAL (RM911U)

DTC P0171, P0172, P0174 or P0175 IS CAUSED BY RUNNING OUT OF FUEL

051LQ-06

ENGINE CONTROL SYSTEM Check Sheet

Customer’s Name

Driver’s Name

Data Vehicle
Brought in

License No.

Model and Model
Year

Frame No.

Engine Model

Odometer Reading

km
miles

Problem Symptoms

Engine does
not Start

Difficult to
Start

Poor Idling

Poor
Drivability

Engine Stall

Others

Engine does not crank

No initial combustion

No complete combustion

Engine cranks slowly

Other

Incorrect first idle

Idling rpm is abnormal

High ( rpm)

Low ( rpm)

Rough idling

Other

Hesitation

Back fire

Muffler explosion (after-fire)

Surging

Knocking

Other

Soon after starting

After accelerator pedal depressed

After accelerator pedal released

During A/C operation

Shifting from N to D

Other

Datas Problem
Occurred

Problem Frequency

Condition When

Problem Occurs

Weather

Engine Operation

Engine Temp.

Place

Outdoor

Temperature

Constant

Sometimes ( times per day/month)

Once only

Other

Fine

Cloudy

Rainy

Snowy

Various/Other

Hot

Warm

Cool

Cold (approx.

°

F/

°

C)

Highway

Suburbs

Inner City

Uphill

Downhill

Rough road

Other

Cold

Warming up

After Warming up

Any temp.

Other

Starting

Just after starting ( min.)

Idling

Racing

Driving

Constant speed

Acceleration

Deceleration

A/C switch ON/OFF

Other

Condition of

malfunction indicator light

(MIL)

Remains on

Sometimes light up

Does not light up

Normal

Malfunction code(s) (code )

Freezed frame data ( )

Normal

Malfunction code(s) (code )

Freezed frame data ( )

Normal mode
(Precheck)

Check Mode

DTC Inspection

Inspector’s
Name

05-4

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DIAGNOSTICS

SFI SYSTEM (1MZ-FE)

157

2002 LEXUS ES300 REPAIR MANUAL (RM911U)

CUSTOMER PROBLEM ANALYSIS CHECK