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 A/F sensor heater (see  INSPECTION  ).  
   1. NG : Replace A/F 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)

   Fig 1: Identifying EFI Main Relay

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
   1. NG : Replace EFI main relay. 
   2. OK : Go to next step. 
3. Check voltage between terminal HA1A 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 HA1A of the ECM connector and body ground.

   OK: 

   Voltage: 9 to 14 V 

   1. OK : Replace ECM (see  COMPONENTS  ).  
   2. NG : Go to next step. 
      Fig 2: Locating HA1A (+) Connector Terminal Of ECM

      Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
4. Check for open and short in wire harness between EFI main relay and A/F sensor, and A/F 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  ).