Inspection Procedure

HINT:

• Read freeze frame data using the intelligent tester. 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.
• If DTC P0420 is displayed, check the bank 1 catalyst.
• If DTC P0430 is displayed, check the bank 2 catalyst.
• Bank 1 includes No. 1 cylinder, but bank 2 does not. No. 1 cylinder is located in the front part of the engine, opposite the transmission.

1. CHECK OTHER DTC OUTPUT (IN ADDITION TO DTC P0420, P0430) 
   1. Connect the intelligent tester to the CAN VIM. Then connect the CAN VIM to the DLC3.
   2. Turn the engine switch on (IG) and turn the tester ON.
   3. Enter the following menus: DIAGNOSIS / ENHANCED OBD II / DTC INFO / CURRENT CODES.
   4. Read the DTCs.

   Result 

   RESULT CHART
   
   

   Display (DTC output)	Proceed to
   P0420 or P0430	A
   P0420 or P0430 and other DTCs	B

   B: GO TO RELEVANT DTC CHART 

   A: Go to next step 

2. CHECK FOR EXHAUST GAS LEAKAGE 

   NG: REPAIR OR REPLACE EXHAUST GAS LEAKAGE POINT 

   OK: Go to next step 

3. INSPECT HEATED OXYGEN SENSOR (RESISTANCE) 
   1. Disconnect the E23, E44, K34 and K57 sensor connectors.
   2. Measure the resistance of the sensor.

      Standard resistance: Sensor 1 

      TESTER CONNECTION SPECIFIED CONDITION
      
      

      Tester Connection	Specified Condition
      1 (HT1A) - 2 (+B)	11 to 16 Ω
      1 (HT2A) - 2 (+B)	11 to 16 Ω
      1 (HT1A) - 4 (E2)	10 kΩ or higher
      1 (HT2A) - 4 (E2)	10 kΩ or higher

      Standard resistance: Sensor 2 

      TESTER CONNECTION SPECIFIED CONDITION
      
      

      Tester Connection	Specified Condition
      1 (HT1B) - 2 (+B)	11 to 16 Ω
      1 (HT2B) - 2 (+B)	11 to 16 Ω
      1 (HT1B) - 4 (E2)	10 kΩ or higher
      1 (HT2B) - 4 (E2)	10 kΩ or higher

   Fig 1: Identifying E23, E44, K34 And K57 Sensor Connectors

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

   NG: REPLACE HEATED OXYGEN SENSOR 

   OK: Go to next step 

4. PERFORM ACTIVE TEST 

   HINT:

   It is possible that the malfunctioning area can be found using the ACTIVE TEST A/F CONTROL operation. The ACTIVE TEST can determine if the heated oxygen sensor or other potential trouble areas are malfunctioning or not.

   The injection volume can be switched to -12.5% (decrease) or +25% (increase) by the ACTIVE TEST.

   The ACTIVE TEST procedure enables a technician to check and graph the output voltage of the heated oxygen sensors.

   Procedure:

   1. Connect the intelligent tester to the CAN VIM. Then connect the CAN VIM to the DLC3.
   2. Turn the engine switch on (IG).
   3. Warm up the engine by running the engine at 2,500 rpm for approximately 90 seconds.
   4. Enter the following menus: DIAGNOSIS / ENHANCED OBD II / ACTIVE TEST / A/F CONTROL.
   5. Perform the ACTIVE TEST while the engine is idling.

      Standard: 

      Heated oxygen sensor reacts in accordance with the increase and decrease of injection volume: 

      +25% → RICH output: More than 0.55 V 

      -12.5% → LEAN output: Less than 0.4 V 

      NOTE: The heated oxygen sensor (sensor 1) output has a few seconds of delay and the heated oxygen sensor (sensor 2) output has a maximum of 20 seconds of delay. If the vehicle is short on fuel, the air-fuel ratio becomes LEAN and the DTCs will be recorded.
   Fig 2: Heated Oxygen Sensor Voltage Chart

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

   NG: REPLACE HEATED OXYGEN SENSOR 

   OK: Go to next step 

5. REPLACE CATALYST CONVERTER (BANK 1 OR BANK 2) AND FRONT EXHAUST PIPE 
   NOTE: Replace both the front catalyst and rear catalyst (front exhaust pipe) of the damaged bank.

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