DTC P0420: Catalyst System Efficiency Below Threshold (Bank 1); DTC P0430: Catalyst System Efficiency Below Threshold (Bank 2): Procedure
- CHECK OTHER DTC OUTPUT (IN ADDITION TO DTC P0420, P0430)
- Connect the Techstream to the DLC3.
- Turn the ignition switch ON and turn the tester ON.
- Enter the following menus: Powertrain / Engine and ECT / Trouble Codes.
- Read the DTCs.
Result
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
- CHECK FOR EXHAUST GAS LEAKAGE
NG → REPAIR OR REPLACE EXHAUST GAS LEAKAGE POINT
OK: Go to next step
- INSPECT HEATED OXYGEN SENSOR (RESISTANCE)
Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
- Disconnect the H9, H10, H15 and H16 sensor connectors.
- Measure the resistance of the sensor.
Standard resistance (bank 1 sensor 1)
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 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 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 1 (+B) - 2 (HT) 11 to 16 Ω 1 (+B) - 3 (E) 10 kΩ or higher
NG → REPLACE HEATED OXYGEN SENSOR
OK: Go to next step
- PERFORM ACTIVE TEST USING 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:
- Connect the Techstream to the DLC3.
- Turn the ignition switch ON.
- Warm up the engine by running the engine at 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 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.
Case Front HO2 Sensor (Sensor 1) Output Voltage Rear HO2 Sensor (Sensor 2) Output Voltage Main Suspected Trouble Area 1 - 2 - Front HO2 sensor
- Front HO2 sensor heater
- Front HO2 sensor circuit
3 - Rear HO2 sensor
- Rear HO2 sensor heater
- Rear HO2 sensor circuit
4 - 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
- Procedure:
- 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 is output A P0430 is output B P0420 and P0430 are output A and B
B → See step 7
A → See step 6
- According to the output DTCs in the step 1 (CHECK ANY OTHER DTCS OUTPUT), proceed to next step referring to the table below.
- REPLACE CATALYST CONVERTER (for Bank 1)
- Replace the catalyst converter (for Bank 1). Refer to REMOVAL .
NEXT → REPLACE EXHAUST FRONT PIPE
- REPLACE CATALYST CONVERTER (for Bank 2)
- Replace the catalyst converter (for Bank 2). Refer to REMOVAL .
NEXT → REPLACE EXHAUST FRONT PIPE