DTC P0420 Catalyst System Efficiency Below Threshold (Bank 1); DTC P0430 Catalyst System Efficiency Below Threshold (Bank 2): Wiring Diagram
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.
- CHECK OTHER DTC OUTPUT (IN ADDITION TO DTC P0420, P0430)
- Connect the intelligent tester to the CAN VIM. Then connect the CAN VIM to the DLC3.
- Turn the engine switch on (IG) and turn the tester ON.
- Enter the following menus: DIAGNOSIS / ENHANCED OBD II / DTC INFO / CURRENT CODES.
- Read the DTCs.
Result
DIAGNOSTIC TROUBLE CODE CHARTDisplay (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)
- Disconnect the E23, E44, L34 and L57 sensor connectors.
- Measure the resistance of the sensor.
Standard resistance: Sensor 1
TESTER CONNECTION AND SPECIFIED CONDITION CHARTTester 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 AND SPECIFIED CONDITION CHARTTester 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
NG : REPLACE HEATED OXYGEN SENSOR
OK : GO TO NEXT STEP.
- 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:
- Connect the intelligent tester to the CAN VIM. Then connect the CAN VIM to the DLC3.
- Turn the engine switch on (IG).
- Warm up the engine by running the engine at 2,500 RPM for approximately 90 seconds.
- Enter the following menus: DIAGNOSIS / ENHANCED OBD II / ACTIVE TEST / A/F CONTROL.
- 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.INJECTION VOLUME SPECIFICATIONSCase Heated Oxygen Sensor (sensor 1) Voltage Heated Oxygen Sensor (sensor 2) Voltage Main Suspected Trouble Area 1 Injection Volume
+25%
-12.5%Injection Volume
+25%
-12.5%- Heated oxygen sensor Voltage 0.55 V or more Below 0.4 V Heated oxygen sensor Voltage 0.5 V or more Below 0.4 V 2 Injection Volume
+25%
-12.5%Injection Volume
+25%
-12.5%Heated oxygen sensor (sensor 1)
Heated oxygen sensor heater (sensor 1)Heated oxygen sensor Voltage Almost no reaction Heated oxygen sensor Voltage 0.5 V or more Below 0.4 V 3 Injection Volume
+25%
-12.5%Injection Volume
+25%
-12.5%Heated oxygen sensor (sensor 2)
Heated oxygen sensor heater (sensor 2)Heated oxygen sensor Voltage 0.55 V or more Below 0.4 V Heated oxygen sensor Voltage Almost no reaction 4 Injection volume
+25%
-12.5%Injection Volume
+25%
-12.5%Injector fuel pressure, Exhaust gas leak, etc. (air-fuel ratio is extremely LEAN or RICH) Heated oxygen sensor Voltage Almost no reaction Heated oxygen sensor Voltage Almost no reaction
NG : REPLACE HEATED OXYGEN SENSOR
OK : GO TO NEXT STEP.
- 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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