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. Check resistance of heated oxygen sensor heater (see  INSPECTION  ).  
   1. NG : Replace heated oxygen sensor. 
   2. OK : Go to next step. 
2. Check EFI main relay. 

   PREPARATION: 

   Remove the EFI main relay from the engine room J/B.

   CHECK: 

   Inspect the EFI main relay.

   OK: 

   TESTER CONNECTION SPECIFIED CONDITION
   
   

   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 EFI main relay. 
   2. OK : Go to next step. 
      Fig 1: Identifying EFI Main Relay

      Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
3. Check voltage between terminals HT1B of ECM connector and body ground. 

   PREPARATION: 

   1. Remove the glove compartment (see COMPONENTS ).
   2. Turn the ignition switch ON.

   CHECK: 

   Measure the voltage between terminal HT1B of the ECM connector and body ground.

   HINT:

   Connect terminal HT1B to bank 1 sensor 2.

   OK: 

   Voltage: 9 to 14 V 

   1. OK : Replace ECM (see  COMPONENTS  ).  
   2. NG : Go to next step. 
      Fig 2: Locating HT1B (+) Connector Terminal Of ECM

      Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
4. Check for open and short in wire harness between EFI main relay and heated oxygen sensor, and heated oxygen sensor and ECM (see  HOW TO USE THE DIAGNOSTIC CHART AND INSPECTION PROCEDURE  in INTRODUCTION article).  
   1. NG : Repair or replace harness and connector. 
   2. OK : Replace ECM (see  COMPONENTS  ).