Toyota FJ Cruiser (GSJ 10, 15 series). Instruction — part 66

1GR-FE ENGINE CONTROL SYSTEM – SFI SYSTEM

ES–219

ES

INSPECTION PROCEDURE

HINT:
Intelligent tester only:
Malfunctioning areas can be identified by performing the A/F CONTROL function provided in the ACTIVE
TEST. The A/F CONTROL function can help to determine whether the Air-Fuel Ratio (A/F) sensor, Heated
Oxygen (HO2) sensor and other potential trouble areas are malfunctioning.
The following instructions describe how to conduct the A/F CONTROL operation using an intelligent
tester.
(1) Connect an intelligent tester to the DLC3.
(2) Start the engine and turn the tester ON.
(3) Warm up the engine at an engine speed of 2,500 rpm for approximately 90 seconds.
(4) Select the following menu items: DIAGNOSIS / ENHANCED OBD II / ACTIVE TEST / A/F CONTROL.
(5) Perform the A/F CONTROL operation with the engine in an idling condition (press the RIGHT or LEFT
button to change the fuel injection volume).
(6) Monitor the voltage outputs of the A/F and HO2 sensors (AFS B1S1 and O2S B1S2 or AFS B2S1 and
O2S B2S2) displayed on the tester.
HINT:
•

The A/F CONTROL operation lowers the fuel injection volume by 12.5 % or increases the injection
volume by 25 %.

•

Each sensor reacts in accordance with increases and decreases in the fuel injection volume.

Standard

Tester Display

(Sensor)

Injection Volumes

Status

Voltages

AFS B1S1 or AFS B2S1

(A/F)

+25 %

Rich

Less than 3.0

AFS B1S1 or AFS B2S1

(A/F)

-12.5 %

Lean

More than 3.35

O2S B1S2 or O2S B2S2

(HO2)

+25 %

Rich

More than 0.55

O2S B1S2 or O2S B2S2

(HO2)

-12.5 %

Lean

Less than 0.4

Voltage output when active air-fuel ratio control not performed

Normal Catalyst

Deteriorated Catalyst

Waveform of
HO2 Sensor
behind TWC

Waveform of
A/F Sensor in
front of TWC

3.5 V

3.0 V

1.0 V

0 V

10 seconds

10 seconds

A121610E01

ES–220

1GR-FE ENGINE CONTROL SYSTEM – SFI SYSTEM

ES

NOTICE:
The Air-Fuel Ratio (A/F) sensor has an output delay of a few seconds and the Heated Oxygen
(HO2) sensor has a maximum output delay of approximately 20 seconds.

•

Following the A/F CONTROL procedure enables technicians to check and graph the voltage outputs of
both the A/F and HO2 sensors.

•

To display the graph, select the following menu items on the tester: DIAGNOSIS / ENHANCED OBD II
/ ACTIVE TEST / A/F CONTROL / USER DATA / AFS B1S1 and O2S B1S2 or AFS B2S1 and O2S
B2S2, and press the YES button and then the ENTER button followed by the F4 button.

HINT:
Read freeze frame data using an intelligent tester. Freeze frame data record the engine condition when
malfunctions are detected. When troubleshooting, freeze frame data can help determine if the vehicle was
moving or stationary, if the engine was warmed up or not, if the air-fuel ratio was lean or rich, and other
data, from the time the malfunction occurred.

(a) Connect an intelligent tester to the DLC3.
(b) Turn the ignition switch ON and turn the tester ON.
(c) Select the following menu items: DIAGNOSIS /

ENHANCED OBD II / DTC INFO / CURRENT CODES.

(d) Read DTCs.

Result

Case

A/F Sensor (Sensor 1)

Output Voltage

HO2 Sensor (Sensor 2)

Output Voltage

Main Suspected

Trouble Areas

1

Injection volume

+25 %

-12.5 %

Injection volume

+25 %

-12.5 %

-

Output voltage

More than 3.35 V

Less than 3.0 V

Output voltage

More than 0.55 V

Less than 0.4 V

2

Injection volume

+25 %

-12.5 %

Injection volume

+25 %

-12.5 %

•

A/F sensor

•

A/F sensor heater

•

A/F sensor circuit

Output voltage

Almost

no reaction

Output voltage

More than 0.55 V

Less than 0.4 V

3

Injection volume

+25 %

-12.5 %

Injection volume

+25 %

-12.5 %

•

HO2 sensor

•

HO2 sensor heater

•

HO2 sensor circuit

Output voltage

More than 3.35 V

Less than 3.0 V

Output voltage

Almost

no reaction

4

Injection volume

+25 %

-12.5 %

Injection volume

+25 %

-12.5 %

•

Injector

•

Fuel pressure

•

Gas leakage from
exhaust system

(Air-fuel ratio extremely
lean or rich)

Output voltage

Almost

no reaction

Output voltage

Almost

no reaction

1

CHECK ANY OTHER DTCS OUTPUT (IN ADDITION TO DTC P0420 AND/OR P0430)

Display (DTC Output)

Proceed To

P0420 and/or P0430

A

P0420 and/or P0430 and other DTCs

B

1GR-FE ENGINE CONTROL SYSTEM – SFI SYSTEM

ES–221

ES

HINT:
If any DTCs other than P0420 or P0430 are output,
troubleshoot those DTCs first.

B

A

(a) Connect an intelligent tester to the DLC3.
(b) Start the engine and turn the tester ON.
(c) Warm up the engine at an engine speed of 2,500 rpm for

approximately 90 seconds.

(d) Select the following menu items: DIAGNOSIS /

ENHANCED OBD II / ACTIVE TEST / A/F CONTROL.

(e) Perform the A/F CONTROL operation with the engine in

an idling condition (press the RIGHT or LEFT button to
change the fuel injection volume).

(f)

Monitor the voltage outputs of the A/F and HO2 sensors
(AFS B1S1 and O2S B1S2 or AFS B2S1 and O2S
B2S2) displayed on the tester.
HINT:
•

The A/F CONTROL operation lowers the fuel injection
volume by 12.5 % or increases the injection volume
by 25 %.

•

Each sensor reacts in accordance with increases and
decreases in the fuel injection volume.

Standard

Result

GO TO DTC CHART (See page

ES-57

)

2

PERFORM ACTIVE TEST USING INTELLIGENT TESTER (A/F CONTROL)

Tester Display

(Sensor)

Injection Volumes

Status

Voltages

AFS B1S1 or AFS B2S1

(A/F)

+25 %

Rich

Less than 3.0

AFS B1S1 or AFS B2S1

(A/F)

-12.5 %

Lean

More than 3.35

O2S B1S2 or O2S B2S2

(HO2)

+25 %

Rich

More than 0.55

O2S B1S2 or O2S B2S2

(HO2)

-12.5 %

Lean

Less than 0.4

Status

AFS B1S1

or

AFS B2S1

Status

O2S B1S2

or

O2S B2S2

A/F Condition and A/F and

HO2 Sensors Conditions

Misfires

Main Suspected Trouble Areas

Proceed

To

Lean/Rich

Lean/Rich

Normal

-

•

Three-Way Catalytic Converter (TWC)

•

Gas leakage from exhaust system

A

Lean

Lean/Rich

A/F sensor malfunction

-

•

A/F sensor

B

Rich

Lean/Rich

A/F sensor malfunction

-

•

A/F sensor

Lean/Rich

Lean

HO2 sensor malfunction

-

•

HO2 sensor

•

Gas leakage from exhaust system

C

Lean/Rich

Rich

HO2 sensor malfunction

-

•

HO2 sensor

•

Gas leakage from exhaust system

ES–222

1GR-FE ENGINE CONTROL SYSTEM – SFI SYSTEM

ES

Lean: During A/F CONTROL, the A/F sensor output
voltage (AFS) is consistently more than 3.35 V, and
the HO2 sensor output voltage (O2S) is consistently
less than 0.4 V.
Rich: During A/F CONTROL, the AFS is consistently
less than 3.0 V, and the O2S is consistently more than
0.55 V.
Lean/Rich: During A/F CONTROL of the ACTIVE
TEST, the output voltage of the HO2 sensor
alternates correctly.

B

C

A

OK:

No gas leakage.

NG

OK

Lean

Lean

Actual air-fuel ratio lean

May occur

•

Extremely rich or lean actual air-fuel
ratio

•

Gas leakage from exhaust system

A

Rich

Rich

Actual air-fuel ratio rich

-

•

Extremely rich or lean actual air-fuel
ratio

•

Gas leakage from exhaust system

Status

AFS B1S1

or

AFS B2S1

Status

O2S B1S2

or

O2S B2S2

A/F Condition and A/F and

HO2 Sensors Conditions

Misfires

Main Suspected Trouble Areas

Proceed

To

CHECK AND REPLACE AIR FUEL RATIO
SENSOR

CHECK AND REPLACE HEATED OXYGEN
SENSOR, AND CHECK AND REPAIR
EXHAUST GAS LEAKAGE

3

CHECK FOR EXHAUST GAS LEAKAGE

REPAIR OR REPLACE EXHAUST GAS
LEAKAGE POINT

REPLACE THREE-WAY CATALYTIC CONVERTER