Inspection Procedure

WARNING: This page is about a different variant/trim than selected.

HINT:

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.

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

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

Reconnect the air fuel ratio sensor connector.
NG: REPLACE AIR FUEL RATIO SENSOR (See REMOVAL )

Fig 1: Identifying Air Fuel Ratio Sensor Connector Terminals
Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

OK: Go to Next Step

CHECK TERMINAL VOLTAGE (POWER SOURCE)

Disconnect the air fuel ratio sensor connector.
Turn the ignition switch to ON.

Measure the voltage according to the value(s) in the table below.

Standard Voltage

TESTER CONNECTION SPECIFIED CONDITION CHART

Tester Connection	Switch Condition	Specified Condition
B37-2 (+B) - Body ground	Ignition switch ON	11 to 14 V

Reconnect the air fuel ratio sensor connector.
NG: Go to step 5

Fig 2: Identifying B37 Air Fuel Ratio Sensor Connector Terminals
Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

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
B37-1 (HA1A) - B29-109 (HA1A)	Always	Below 1 Ω

Standard Resistance (Check for Short)

TESTER CONNECTION SPECIFIED CONDITION CHART

Tester Connection	Condition	Specified Condition
B37-1 (HA1A) or B29-109 (HA1A) - Body ground	Always	10 kΩ or higher

Reconnect the air fuel ratio sensor connector.
Reconnect the ECM connector.
NG: REPAIR OR REPLACE HARNESS OR CONNECTOR (AIR FUEL RATIO SENSOR ECM)

Fig 3: Identifying Air Fuel Ratio Sensor Connector And ECM Connector
Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

OK: Go to Next Step

CHECK WHETHER DTC OUTPUT RECURS (DTC P0031 OR P0032)

Connect the Techstream to the DLC3.
Turn the ignition switch to ON.
Turn the Techstream on.
Clear DTCs (See DTC CHECK / CLEAR ).
Start the engine.
Allow the engine to idle for 1 minute or more.
Enter the following menus: Powertrain / Engine and ECT / Trouble Codes.

Read the DTCs.

Result

RESULT CHART

Result	Proceed to
DTC is not output	A
DTC P0031 or P0032 is output	B

B: REPLACE ECM (See REMOVAL )

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

INSPECT FUSE (EFI NO. 2 FUSE)

Remove the EFI No. 2 fuse from the engine room relay block.

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

Standard Resistance

TESTER CONNECTION SPECIFIED CONDITION CHART

Tester Connection	Condition	Specified Condition
EFI No. 2 fuse	Always	Below 1 Ω

Reinstall the EFI No. 2 fuse.
NG: REPLACE FUSE (EFI NO. 2)

Fig 4: Identifying EFI No. 2 Fuse
Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

OK: REPAIR OR REPLACE HARNESS OR CONNECTOR (INTEGRATION RELAY (EFI MAIN RELAY) AIR FUEL RATIO SENSOR)