Inspection Procedure

HINT:

• Read freeze frame data using the Techstream. 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 Techstream to the DLC3.
   2. Turn the ignition switch ON and turn the tester ON.
   3. Enter the following menus: Powertrain / Engine and ECT / Trouble 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 H9, H10, H15 and H16 sensor connectors.
   2. Measure the resistance of the sensor.

   Standard resistance (bank 1 sensor 1) 

   TESTER CONNECTION SPECIFIED CONDITION CHART
   
   

   Tester Connection	Specified Condition
   1 (HT) - 2 (+B)	11 to 16 Ω
   1 (HT) - 4 (E1)	10 kΩ or higher

   Standard resistance (bank 2 sensor 1) 

   TESTER CONNECTION SPECIFIED CONDITION CHART
   
   

   Tester Connection	Specified Condition
   1 (HT) - 2 (+B)	11 to 16 Ω
   1 (HT) - 4 (E1)	10 kΩ or higher

   Standard resistance (bank 1 sensor 2) 

   TESTER CONNECTION SPECIFIED CONDITION CHART
   
   

   Tester Connection	Specified Condition
   1 (+B) - 2 (HT)	11 to 16 Ω
   1 (+B) - 3 (E)	10 kΩ or higher

   Standard resistance (bank 2 sensor 2) 

   TESTER CONNECTION SPECIFIED CONDITION CHART
   
   

   Tester Connection	Specified Condition
   1 (+B) - 2 (HT)	11 to 16 Ω
   1 (+B) - 3 (E)	10 kΩ or higher

   NG: REPLACE HEATED OXYGEN SENSOR 

   Fig 1: Inspecting Heated Oxygen Sensor (Resistance)

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

   OK: Go to next step 

4. PERFORM ACTIVE TEST BY TECHSTREAM (A/F CONTROL) 

   HINT:

   It is possible that the malfunctioning area can be found using the Active Test Control the Injection Volume for A/F sensor 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 Techstream to the DLC3.
   2. Turn the ignition switch ON.
   3. Warm up the engine by running the engine at 2500 rpm for approximately 90 seconds.
   4. Enter the following menus: Powertrain / Engine and ECT / Active Test / Control the Injection Volume for A/F sensor.
   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.
   FRONT HO2 SENSOR VOLTAGE CHART
   
   

   Case	Front HO2 Sensor (Sensor 1) Output Voltage	Rear HO2 Sensor (Sensor 2) Output Voltage	Main Suspected Trouble Area
   1	Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002	Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002	-
   2	Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002	Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002	Front HO2 sensor Front HO2 sensor heater Front HO2 sensor circuit
   3	Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002	Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002	Rear HO2 sensor Rear HO2 sensor heater Rear HO2 sensor circuit
   4	Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002	Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002	Injector Fuel pressure Gas leakage from exhaust system (Air-fuel ratio extremely rich or lean)

   NG: REPLACE HEATED OXYGEN SENSOR 

   OK: Go to next step 

5. CHECK DTC OUTPUT (DTC P0420 AND/OR P0430) 
   1. According to the output DTCs in the step 1 (CHECK ANY OTHER DTCS OUTPUT), proceed to next step referring to the table below.

      A:  Go to step  6

      B:  Go to step  7

6. REPLACE CATALYST CONVERTER (for Bank 1) 
   1. Replace the catalyst converter (for Bank 1) (See REMOVAL ).

   NEXT: REPLACE EXHAUST FRONT PIPE 

7. REPLACE CATALYST CONVERTER (for Bank 2) 
   1. Replace the catalyst converter (for Bank 2) (See REMOVAL ).

      NEXT: REPLACE EXHAUST FRONT PIPE