Inspection Procedure

HINT:

Read freeze frame data using the hand-held tester or the OBD II scan tool. Freeze frame data records the engine conditions when a malfunction is detected. When troubleshooting, freeze frame data can help determine if the vehicle was running or stopped, 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 A6 A/F sensor connector.
   2. Measure the resistance of the A/F sensor.
      Fig 1: Identifying A/F Sensor Connector Terminal

      Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

      Standard: 

      TESTER CONNECTION AND CONDITION SPECIFICATIONS
      
      

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

   1. NG: REPLACE AIR FUEL RATIO SENSOR 
   2. OK: GO TO NEXT STEP. 
2. INSPECT RELAY (EFI) 
   1. Remove the EFI relay from the engine room J/B.
   2. Measure the resistance of the EFI relay.
      Fig 2: Identifying Relay Terminals

      Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

      Standard: 

      TESTER CONNECTION AND CONDITION SPECIFICATIONS
      
      

      Tester Connection	Specified Condition
      3 - 5	10 kΩ or higher
      3 - 5	Below 1 Ω (when battery voltage is applied to terminals 1 and 2)

   1. NG: REPLACE RELAY 
   2. OK: GO TO NEXT STEP. 
3. CHECK ECM (HA1A VOLTAGE) 
   1. Turn the ignition switch ON.
   2. Measure the voltage of the ECM connectors.
      Fig 3: Identifying ECM E8 & E9 Connector Terminals

      Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

      Standard: 

      TESTER CONNECTION AND CONDITION SPECIFICATIONS
      
      

      Tester Connection	Specified Condition
      E8-5 (HA1A) - E9-1 (E1)	9 to 14 V

   1. OK: REPLACE ECM (See  REPLACEMENT  ) 
   2. NG: GO TO NEXT STEP. 
4. CHECK WIRE HARNESS (ECM - A/F SENSOR, A/F SENSOR - EFI RELAY) 
   1. Check the wire harness between the ECM and A/F sensor.
      1. Disconnect the E8 ECM connector.
      2. Disconnect the A6 A/F sensor connector.
      3. Measure the resistance of the wire harness side connectors.
         Fig 4: Identifying ECM E8 & A/F Sensor Connector Terminals

         Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

         Standard: 

         TESTER CONNECTION AND CONDITION SPECIFICATIONS
         
         

         Tester Connection	Specified Condition
         A6-1 (HT)- E8-5 (HA1A)	Below 1 Ω
         A6-1 (HT) or E8-5 (HA1 A) - Body ground	10 kΩ or higher

   2. Check the wire harness between the A/F sensor and EFI relay.
      1. Disconnect the A6 A/F sensor connector.
      2. Remove the EFI relay from the engine room J/B.
      3. Measure the resistance of the wire harness side connectors.
         Fig 5: Identifying A/F Sensor Connector Terminals & EFI Relay Location

         Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

         Standard: 

         TESTER CONNECTION AND CONDITION SPECIFICATIONS
         
         

         Tester Connection	Specified Condition
         A6-2 (+B) - J/B EFI relay terminal 3	Below 1 Ω
         A6-2 (+B) or J/B EFI relay terminal 3 - Body ground	10 kΩ or higher

   1. NG: REPAIR OR REPLACE HARNESS AND CONNECTOR 
   2. OK: REPLACE ECM (See  REPLACEMENT  )