Inspection Procedure

HINT:

Read freeze frame data using Techstream. Freeze frame data records 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.

1. INSPECT AIR-FUEL RATIO SENSOR (HEATER RESISTANCE) 
   1. Disconnect the B7 A/F sensor connector.
   2. Measure the resistance of the A/F sensor connector.

      Standard resistance 

      RESISTANCE SPECIFICATION
      
      

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

      Fig 1: Identifying A/F Sensor Connector Terminals

      Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
   3. Reconnect the A/F sensor connector.

   NG: REPLACE AIR-FUEL RATIO SENSOR 

   OK: Go to Next Step 

2. CHECK TERMINAL VOLTAGE (+B OF A/F SENSOR) 
   1. Disconnect the B7 A/F sensor connector.
   2. Turn the ignition switch ON.
   3. Measure the voltage between the terminals of the B7 A/F sensor connector and body ground.

      Standard voltage 

      VOLTAGE SPECIFICATION
      
      

      Tester Connections	Specified Conditions
      B7-2 (+B) - Body ground	9 to 14 V

      Fig 2: Identifying A/F Sensor Connector Terminals

      Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
   4. Reconnect the A/F sensor connector.

   OK:  Go to step  5

   NG: Go to Next Step 

3. INSPECT INTEGRATION RELAY (EFI MAIN RELAY) 
   1. Remove the integration relay from the engine room No. 1 relay block.
   2. Inspect the EFI MAIN fuse.
      1. Remove the EFI MAIN fuse from the integration relay.
      2. Measure the EFI MAIN fuse resistance.

         Standard resistance: 

         Below 1 Ω 

      3. Reinstall the EFI MAIN fuse.
   3. Inspect the EFI MAIN relay.
      1. Measure the EFI MAIN relay resistance.

         Standard resistance 

         RESISTANCE SPECIFICATION
         
         

         Tester Connections	Specified Conditions
         1C-1 - 1A-4	10 kΩ or higher
         	Below 1 Ω (Apply battery voltage between terminals 1A-2 and 1A-3)

   4. Reinstall the integration relay.
   Fig 3: Identifying Integration Relay Connector Terminals
   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

   NG: REPLACE INTEGRATION RELAY 

   OK: Go to Next Step 

4. CHECK HARNESS AND CONNECTOR (A/F SENSOR - EFI RELAY) 
   1. Check the EFI No. 1 fuse.
   2. Disconnect the B7 A/F sensor connector.
      Fig 4: Identifying A/F Sensor Connector Terminals

      Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
   3. Remove the integration relay from the engine room No. 1 relay block.
   4. Check the resistance.

      Standard resistance (Check for open) 

      RESISTANCE SPECIFICATION
      
      

      Tester Connections	Specified Conditions
      B7-2 (+B) - 1A-4 (Engine room No. 1 R/B)	Below 1 Ω

      Standard resistance (Check for short) 

      RESISTANCE SPECIFICATION
      
      

      Tester Connections	Specified Conditions
      B7-2 (+B) or 1A-4 (Engine room No. 1 R/B) - Body ground	10 kΩ or higher

   5. Reconnect the A/F sensor connector.
   6. Reinstall the integration relay.

   NG: REPAIR OR REPLACE HARNESS OR CONNECTOR 

   OK: CHECK ECM POWER SOURCE CIRCUIT 

5. CHECK HARNESS AND CONNECTOR (A/F SENSOR - ECM) 
   1. Disconnect the B7 A/F sensor connector.
   Fig 5: Identifying A/F Sensor And ECM Connector Terminals
   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
   2. Disconnect the B30 ECM connector.
   3. Measure the resistance.

      Standard resistance (Check for open) 

      RESISTANCE SPECIFICATION
      
      

      Tester Connections	Specified Conditions
      B7-1 (HA1A) - B30-109 (HA1A)	Below 1 Ω

      Standard resistance (Check for short) 

      RESISTANCE SPECIFICATION
      
      

      Tester Connections	Specified Conditions
      B7-1 (HA1A) or B30-109 (HA1A) - Body ground	10 kΩ or higher

   4. Reconnect the A/F sensor connector.
   5. Reconnect the ECM connector.

   NG: REPAIR OR REPLACE HARNESS OR CONNECTOR 

   OK: Go to Next Step 

6. CHECK WHETHER DTC OUTPUT RECURS 
   1. Connect Techstream to the DLC3.
   2. Turn the ignition switch ON.
   3. Turn the tester ON.
   4. Clear DTCs (see DTC CHECK / CLEAR  ).
   5. Start the engine.
   6. Allow the engine to idle for 1 minute or more.
   7. Select the following menu items: Powertrain / Engine and ECT / Trouble Code.
   8. Read DTCs.

      Result 

      RESULT REFERENCE
      
      

      Display (DTC Output)	Proceed To
      No output	A
      P0031 or P0032	B

   B: REPLACE ECM 

   A: CHECK FOR INTERMITTENT PROBLEMS