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. Are there any other codes (besides P0420) being output? 

   HINT:

   If any other codes besides P0420 are output, perform the troubleshooting for those DTCs first.

   1. YES : Go to relevant DTC chart (see  DIAGNOSTIC TROUBLE CODE CHART  ).  
   2. NO : Go to next step. 
2. Check gas leakage in exhaust system. 
   1. NG : Repair or replace. 
   2. OK : Go to next step. 
3. Check A/F sensor (bank 1 sensor 1) (see  INSPECTION  ).  
   1. NG : Replace A/F sensor. 
   2. OK : Go to next step. 
4. Check heated oxygen sensor (bank 1 sensor 2) (see  INSPECTION  ).  
   1. NG : Replace heated oxygen sensor. 
   2. OK : Go to next step. 

Replace the front and rear three-way catalytic converter in bank malfunction is detected. 

HINT:

Hand-held tester only:

The following procedure enables a technician to identify a trouble area if there is a malfunction in both front A/F sensor or rear heated oxygen sensor other than the catalyst converter, or the malfunction that indicates the actual air-fuel ratio extremely RICH or LEAN.

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

Perform ACTIVE TEST A/F CONTROL operation.

HINT:

The A/F CONTROL operation lowers the injection volume 12.5 % or increases the injection volume 25 %.

1. Connect the hand-held tester to the DLC3 on the vehicle.
2. Turn the ignition switch ON.
3. Warm up the engine with the engine speed 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 A/F CONTROL operation with the engine idle (press the right or left button).

   Result: 

   Heated oxygen sensor reacts in accordance with increase and decrease of injection volume +25 % --> rich output: More than 0.5 V - 12.5 % --> lean output: Less than 0.4 V 

The following A/F CONTROL procedure enables a technician to check and graph the voltage output of the heated oxygen sensors (sensor 1 and 2).

For displaying the graph indication, enter "ACTIVE TEST/ A/F CONTROL / USER DATA" then select "AFS B1S1 and O2S B1S2" by pressing "YES" button and push "ENTER" button before pressing "F4" button.