Inspection Procedure

HINT

Malfunctioning areas can be identified by performing the Control the Injection Volume for A/F sensor function provided in the Active Test. The Control the Injection Volume for A/F sensor function can help to determine whether the air fuel ratio sensor, heated oxygen sensor and other potential trouble areas are malfunctioning

The following instructions describe how to conduct the Control the Injection Volume for A/F sensor operation using the Techstream

Connect the Techstream to the DLC3
Start the engine and turn the Techstream ON
Warm up the engine at an engine speed of 2500 rpm for approximately 90 seconds.
Enter the following menus. Powertrain / Engine / Active Test / Control the Injection Volume for A/F sensor
Perform the Active Test operation with the engine in an idling condition (press the RIGHT or LEFT button to change the fuel injection volume).

Monitor the output voltages of the air fuel ratio and heated oxygen sensors (AFS B1 S1 and O2S B1 S2 or AFS B2 S1 and O2S B2 S2) displayed on the Techstream

HINT

The Control the Injection Volume for A/F sensor 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.

INSPECTION PROCEDURE CHART

Tester Display (Sensor)	Injection Volume	Status	Voltage
AFS B1 S1 or AFS B2 S1 (Air fuel ratio)	+25%	Rich	Less than 3 0V
AFS B1 S1 or AFS B2 S1 (Air fuel ratio)	-12 5%	Lean	More than 3 35 V
O2S B1 S2 or O2S B2 S2 (Heated oxygen)	+25%	Rich	More than 0 55 V
O2S B1 S2 or O2S B2 S2 (Heated oxygen)	-12 5%	Lean	Less than 0 4V

NOTE: 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.

AIR FUEL RATIO (A/F) SENSOR REFERENCE CHART

Case	Air Fuel Ratio Sensor (Sensor 1) Output Voltage	Heated Oxygen Sensor (Sensor 2) Output Voltage	Main Suspected Trouble Area
1	Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002	Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002	-
2	Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002	Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002	Air fuel ratio sensor Air fuel ratio sensor heater Air fuel ratio sensor circuit
3	Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002	Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002	Heated oxygen sensor Heated oxygen sensor heater Heated oxygen sensor circuit
4	Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002	Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002	Injector Fuel pressure Gas leaks from exhaust system (Air-fuel ratio extremely rich or lean)

Following the Control the Injection Volume for A/F sensor procedure enables technicians to check and graph the voltage outputs of both the air fuel ratio and heated oxygen sensors.
To display the graph, enter the following menus. Powertrain / Engine / Active Test / Control the Injection Volume for A/F Sensor / A/F Control System / AFS B1 S1 and O2S B1 S2 or AFS B2 S1 and O2S B2 S2.

HINT

DTC P2A00 or P2A03 may be also set, when the air fuel ratio is stuck rich or lean
A low air fuel ratio sensor voltage could be caused by a rich air fuel mixture Check for conditions that would cause the engine to run rich.
A high air fuel ratio sensor voltage could be caused by a lean air fuel mixture. Check for conditions that would cause the engine to run lean.
Read freeze frame data using the Techstream. The ECM records vehicle and driving condition information as freeze frame data the moment a DTC is stored. When troubleshooting, freeze frame data can be helpful in determining whether the vehicle was running or stopped, whether the engine was warmed up or not, whether the air fuel ratio was lean or rich, as well as other data recorded at the time of a malfunction.

CHECK ANY OTHER DTCS OUTPUT (IN ADDITION TO DTC P2A00 AND/OR P2A03)

Connect the Techstream to the DLC3
Turn the engine switch on (IG).
Turn the Techstream ON
Enter the following menus. Powertrain / Engine / Trouble Codes.

Read the DTCs

Result

RESULT CHART

Result	Proceed to
DTC P2A00 and/or P2A03 are output	A
DTC P2A00 and/or P2A03 and other DTCs are output	B

HINT.

If any DTCs other than P2A00 or P2A03 are output, troubleshoot those DTCs first.

B: GO TO DTC CHART (See DIAGNOSTIC TROUBLE CODE CHART )

A: Go to next step

INSPECT AIR FUEL RATIO SENSOR (HEATER RESISTANCE)

Disconnect the air fuel ratio sensor connector

Measure the resistance according to the value(s) in the table below

Standard Resistance (Bank 1 Sensor 1)

TESTER CONNECTION SPECIFIED CONDITION CHART

Tester Connection	Condition	Specified Condition
1 (HA1A) - 2 (+B)	20°C (68°F)	1.8 to 3.4 Ω
1 (HA1A) - 4 (A1A-)	Always	10 kΩ or higher

Standard Resistance (Bank 2 Sensor 1)

TESTER CONNECTION SPECIFIED CONDITION CHART

Tester Connection	Condition	Specified Condition
1 (HA2A) - 2 (+B)	20°C (68°F)	1.8 to 3.4 Ω
1 (HA2A) - 4 (A2A-)	Always	10 kΩ or higher

Reconnect the air fuel ratio sensor connector.

Fig 1: Identifying Air Fuel Ratio Sensor Connector

Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

NG: REPLACE AIR FUEL RATIO SENSOR (See REMOVAL )

OK: Go to next step

CHECK HARNESS AND CONNECTOR (AIR FUEL RATIO SENSOR - ECM)

Disconnect the air fuel ratio sensor connector.
Disconnect the ECM connector

Measure the resistance according to the value(s) in the table below

Standard Resistance (Check for Open)

TESTER CONNECTION SPECIFIED CONDITION CHART

Tester Connection	Condition	Specified Condition
E42-1 (HA1A) - E6-5 (HA1A)	Always	Below 1 Ω
E42-3 (A1A+) - E5-23 (A1A+)	Always	Below 1 Ω
E42-4 (A1A-) - E5-22 (A1A-)	Always	Below 1 Ω
E38-1 (HA2A) - E6-6 (HA2A)	Always	Below 1 Ω
E38-3 (A2A+) - E5-21 (A2A+)	Always	Below 1 Ω
E38-4 (A2A-) - E5-20 (A2A-)	Always	Below 1 Ω

Standard Resistance (Check for Short)

TESTER CONNECTION SPECIFIED CONDITION CHART

Tester Connection	Condition	Specified Condition
E42-1 (HA1A) or E6-5 (HA1A) - Body ground	Always	10 kΩ or higher
E42-3 (A1A+) or E5-23 (A1A+) - Body ground	Always	10 kΩ or higher
E42-4 (A1A-) or E5-22 (A1A-) - Body ground	Always	10 kΩ or higher
E38-1 (HA2A) or E6-6 (HA2A) - Body ground	Always	10 kΩ or higher
E38-3 (A2A+) or E5-21 (A2A+) - Body ground	Always	10 kΩ or higher
E38-4 (A2A-) or E5-20 (A2A-) - Body ground	Always	10 kΩ or higher

Fig 2: Identifying Air Fuel Ratio Sensor Connector And ECM Connector

Reconnect the air fuel ratio sensor connector
Reconnect the ECM connector

NG: REPAIR OR REPLACE HARNESS OR CONNECTOR

OK: Go to next step

PERFORM CONFIRMATION DRIVING PATTERN

CHECK WHETHER DTC OUTPUT RECURS (DTC P2A00 AND/OR P2A03)

Connect the Techstream to the DLC3
Turn the engine switch on (IG) and turn the Techstream ON
Enter the following menus: Powertrain / Engine / Trouble Codes / Pending.

Read the DTCs

Result

RESULT CHART

Result	Proceed to
DTC P2A00 and/or P2A03 are output	A
DTC is not output	B

B: CHECK FOR INTERMITTENT PROBLEMS (See CHECK FOR INTERMITTENT PROBLEMS )

A: Go to next step

REPLACE AIR FUEL RATIO SENSOR
1. Replace the air fuel ratio sensor (See REMOVAL )
PERFORM CONFIRMATION DRIVING PATTERN

CHECK WHETHER DTC OUTPUT RECURS (DTC P2A00 AND/OR P2A03)

Connect the Techstream to the DLC3.
Turn the engine switch on (IG) and turn the Techstream ON
Enter the following menus. Powertrain / Engine / Trouble Codes / Pending.

Read the DTCs.

Result

RESULT CHART

Result	Proceed to
DTC is not output	A
DTC P2A00 and/or P2A03 are output	B

B: CHECK EXTREMELY RICH OR LEAN ACTUAL AIR FUEL RATIO (REFER TO DTC P0171 PROCEDURE) (See DTC P0171 SYSTEM TOO LEAN (BANK 1); DTC P0172 SYSTEM TOO RICH (BANK 1); DTC P0174 SYSTEM TOO LEAN (BANK 2); DTC P0175 SYSTEM TOO RICH (BANK 2); DTC P1170 PORT INJECTOR FUEL PERFORMANCE; DTC P117B DIRECT INJECTOR FUEL PERFORMANCE )

A: END