DTC P0420: Catalyst System Efficiency Below Threshold (Bank 1); DTC P0430: Catalyst System Efficiency Below Threshold (Bank 2): Procedure
- CHECK ANY OTHER DTCS OUTPUT (IN ADDITION TO DTC P0420 OR P0430)
- Connect the Techstream to the DLC3.
- Turn the engine switch on (IG) and turn the Techstream on.
- Enter the following menus: Powertrain / Engine and ECT / Trouble Codes.
- Read DTCs.RESULT
Result Proceed to P0420 or P0430 is output A P0420 or P0430 and other DTCs are output B HINT:
If any DTCs other than P0420 or P0430 are output, troubleshoot those DTCs first.
B → See step 5
A: Go to next step
- PERFORM ACTIVE TEST USING TECHSTREAM (A/F CONTROL)
- Connect the Techstream to the DLC3.
- Start the engine and turn the Techstream on.
- Warm up the engine at an engine speed of 2500 rpm for approximately 90 seconds.
- Enter the following menus: Powertrain / Engine and ECT / Active Test / Control the Injection Volume for A/F Sensor.
- Perform the Control the Injection Volume for A/F Sensor operation with the engine in an idling condition (press the RIGHT or LEFT button to change the fuel injection volume).
- Monitor the voltage outputs of the A/F and HO2 sensors (AFS Voltage B1S1 and O2S B1S2 or AFS Voltage B2S1 and O2S B2S2) displayed on the Techstream.
Result
A/F sensor reacts in accordance with increases and decreases in fuel injection volume:
+25% = Rich output
Below 3.1 V
-12.5% = Lean output
Higher than 3.4 V
NOTE:The A/F sensor has an output delay of a few seconds and the HO2 sensor has a maximum output delay of approximately 20 seconds.
Case A/F Sensor (Sensor 1) Output Voltage HO2 Sensor (Sensor 2) Output Voltage Main Suspected Trouble Area 1 - 2 - A/F sensor
- A/F sensor heater
- A/F sensor circuit
3 - HO2 sensor
- HO2 sensor heater
- HO2 sensor circuit
4 - Fuel injector
- Fuel pressure
- Gas leakage from exhaust system (Air-fuel ratio extremely rich or lean)
- Following the Control the Injection Volume for A/F Sensor procedure enables technicians to check and graph the voltage outputs of both the A/F and HO2 sensors.
- To display the graph, enter the following menus: Powertrain / Engine and ECT / Active Test / Control the Injection Volume for A/F Sensor / A/F Control System / AFS Voltage B1S1 and O2S B1S2 or AFS Voltage B2S1 and O2S B2S2.
RESULTResult Proceed to Case 1 A Case 2 B Case 3 C Case 4 D
D → CHECK CAUSE OF EXTREMELY RICH OR LEAN ACTUAL AIR-FUEL RATIO, REPLACE FAULTY AREA AND GO TO NEXT STEP
C → See step 4
B → See step 6
A: Go to next step
- INSPECT FOR EXHAUST GAS LEAK
OK
No gas leakage.
RESULTResult Proceed to NG A OK B B → See step 7
A → REPAIR OR REPLACE EXHAUST GAS LEAK POINT
- INSPECT FOR EXHAUST GAS LEAK
OK
No gas leakage.
NG → REPAIR OR REPLACE EXHAUST GAS LEAK POINT
OK → See step 8
- GO TO DTC CHART. Refer to DIAGNOSTIC TROUBLE CODE CHART
- REPLACE AIR FUEL RATIO SENSOR. Refer to REMOVAL
- CHECK DTC OUTPUT (DTC P0420 AND/OR P0430)
- According to the output DTCs in the step 1 (Check Any Other DTCs Output), proceed to next step referring to the table below.RESULT
Result Proceed to P0420 A P0430 B P0420 and P0430 A and B
B → See step 10
A → See step 9
- According to the output DTCs in the step 1 (Check Any Other DTCs Output), proceed to next step referring to the table below.
- REPLACE HEATED OXYGEN SENSOR. Refer to REMOVAL
- REPLACE FRONT NO. 2 EXHAUST PIPE ASSEMBLY (TWC: FRONT CATALYST AND REAR CATALYST). Refer to REMOVAL
- REPLACE FRONT EXHAUST PIPE ASSEMBLY (TWC: FRONT CATALYST AND REAR CATALYST). Refer to REMOVAL