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Home >> Lexus >> 2012 >> LS 460 AWD V8-4.6L (1UR-FSE) >> Repair and Diagnosis >> A L L Diagnostic Trouble Codes ( DTC ) >> Testing and Inspection >> P Code Charts >> P0430

P0430





1UR-FSE ENGINE CONTROL SYSTEM: SFI SYSTEM: P0420, P0430: Catalyst System Efficiency Below Threshold (Bank 1)
P0430 - Catalyst System Efficiency Below Threshold (Bank 2)

DESCRIPTION

The ECM uses sensors mounted in front of and behind the Three-Way Catalytic Converter (TWC) to monitor its efficiency.

The first sensor, the Air-Fuel Ratio (A/F) sensor, sends pre-catalyst information to the ECM. The second sensor, the Heated Oxygen (HO2) sensor, sends post-catalyst information to the ECM.

In order to detect any deterioration in the TWC, the ECM calculates the Oxygen Storage Capacity (OSC) of the TWC. This calculation is based on the voltage output of the HO2 sensor while performing active air- fuel ratio control, rather than the conventional detecting method, which uses the locus ratio.

The OSC value is an indication of the oxygen storage capacity of the TWC. When the vehicle is being driven with a warm engine, active air-fuel ratio control is performed for approximately 15 to 20 seconds. When it is performed, the ECM deliberately sets the air-fuel ratio to lean or rich levels. If a rich-lean cycle of the HO2 sensor is long, the OSC becomes greater. There is a direct correlation between the OSCs of the HO2 sensor and the TWC.

The ECM uses the OSC value to determine the state of the TWC. If any deterioration has occurred, it illuminates the MIL and sets a DTC.





HINT
- Bank 1 refers to the bank that includes the No. 1 cylinder*.
*: The No. 1 cylinder is the cylinder which is farthest from the transmission.
- Bank 2 refers to the bank that does not include the No. 1 cylinder.
- Sensor 1 refers to the sensor closest to the engine assembly.
- Sensor 2 refers to the sensor farthest away from the engine assembly.

CATALYST LOCATION





MONITOR STRATEGY





TYPICAL ENABLING CONDITIONS





TYPICAL MALFUNCTION THRESHOLDS





MONITOR RESULT

Refer to CHECKING MONITOR STATUS Mode 6 Data.

CONFIRMATION DRIVING PATTERN

HINT
Performing this confirmation driving pattern will activate the catalyst efficiency monitor. This is very useful for verifying the completion of a repair.





1. Connect the Techstream to the DLC3.

2. Turn the engine switch on (IG).

3. Turn the Techstream on.

4. Clear DTCs (even if no DTCs are stored, perform the clear DTC operation).

5. Turn the engine switch off and wait for at least 30 seconds.

6. Turn the engine switch on (IG) and turn the Techstream on.

7. Enter the following menus: Powertrain / Engine / Monitor / Current Monitor.

8. Check that Catalyst Efficiency / Current is Incomplete.

9. Start the engine and warm it up until the engine coolant temperature is 75°C (167°F) or higher [A].

10. Drive the vehicle at approximately 60 km/h (38 mph) for 10 minutes or more [B].

HINT
- Drive the vehicle while keeping the engine load as constant as possible.
- The monitor item will change to Complete as the catalyst efficiency monitor operates [C].

11. Enter the following menus: Powertrain / Engine / Trouble Codes.

12. Check if any DTCs (pending DTCs) are stored.

HINT
If the monitor does not change to Complete, and no pending DTCs are stored, perform the following procedure.

13. Drive the vehicle at a speed between 75 and 100 km/h (47 and 63 mph) for 10 minutes or more [D].

HINT
- Drive the vehicle while keeping the engine load as constant as possible.
- The monitor item will change to Complete as the catalyst efficiency monitor operates [E].

14. Enter the following menus: Powertrain / Engine / Trouble Codes.

15. Check if any DTCs (pending DTCs) are stored.

CONDITIONING FOR SENSOR TESTING

HINT
Perform the operation with the engine speeds and time durations described below prior to checking the waveforms of the A/F and HO2 sensors. This is in order to activate the sensors sufficiently to obtain the appropriate inspection results.





1. Connect the Techstream to the DLC3 [A].

2. Start the engine and warm it up with all the accessories switched off until the engine coolant temperature stabilizes[B].

3. Run the engine at an engine speed between 2500 rpm and 3000 rpm for at least 3 minutes [C].

4. While running the engine at 3000 rpm for 2 seconds, and then 2000 rpm for 2 seconds, check the waveforms of the A/F and HO2 sensors using the Techstream.

HINT
- If the voltage output of either the Air-Fuel Ratio (A/F) or Heated Oxygen (HO2) sensor does not fluctuate, or either of the sensors makes a noise, the sensor may be malfunctioning.
- If the voltage outputs of both the sensors remain lean or rich, the air-fuel ratio may be extremely lean or rich. In such cases, perform Control the Injection Volume for A/F sensor using the Techstream.
- If the Three-Way Catalytic Converter (TWC) has deteriorated, the HO2 sensor (located behind the TWC) voltage output fluctuates up and down frequently, even under normal driving conditions (active air-fuel ratio control is not performed).






INSPECTION PROCEDURE

HINT
Malfunctioning areas can be identified by performing the Control the Injection Volume for A/F sensor function provided in the Active Test. The Control the Injection Volume for A/F sensor function can help to determine whether the Air-Fuel Ratio (A/F) sensor, Heated Oxygen (HO2) sensor and other potential trouble areas are malfunctioning.

The following instructions describe how to conduct the Control the Injection Volume for A/F sensor operation using the Techstream.

(a) Connect the Techstream to the DLC3.
(b) Start the engine and turn the Techstream on.
(c) Warm up the engine at an engine speed of 2500 rpm for approximately 90 seconds.
(d) On the Techstream, enter the following menus: Powertrain / Engine / Active Test / Control the Injection Volume for A/F sensor.
(e) Perform the Active Test operation with the engine idling (press the RIGHT or LEFT button to change the fuel injection volume.)
(f) Monitor the output voltages of the A/F and HO2 sensors (AFS Voltage B1S1 and O2S B1S2 or AFS Voltage B2S1 and O2S B2S2) displayed on the Techstream.

HINT
- The Control the Injection Volume for A/F sensor operation lowers the fuel injection volume by +12.5% or increases the injection volume by -12.5%.
- Each sensor reacts in accordance with increases and decreases in the fuel injection volume.





NOTICE:
The Air-Fuel Ratio (A/F) sensor has an output delay of a few seconds and the Heated Oxygen (HO2) sensor has a maximum output delay of approximately 20 seconds.





- 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 / 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.

HINT
Read freeze frame data using the Techstream. Freeze frame data records the engine condition when malfunctions are detected. When troubleshooting, freeze frame data can help determine if the vehicle was moving or stationary, 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.

PROCEDURE

1. CHECK ANY OTHER DTCS OUTPUT (IN ADDITION TO DTC P0420 AND/OR P0430)

(a) Connect the Techstream to the DLC3.

(b) Turn the engine switch on (IG) and turn the Techstream on.

(c) Enter the following menus: Powertrain / Engine / Trouble Codes.

(d) Read DTCs.

Result:





HINT
If any DTCs other than P0420 or P0430 are output, troubleshoot those DTCs first.

B -- GO TO DTC CHART SFI System
A -- Continue to next step.

2. PERFORM ACTIVE TEST USING TECHSTREAM

(a) Connect the Techstream to the DLC3.

(b) Start the engine and turn the Techstream on.

(c) Warm up the engine at an engine speed of 2500 rpm for approximately 90 seconds.

(d) Enter the following menus: Powertrain / Engine / Active Test / Control the Injection Volume for A/F sensor.

(e) Perform the Control the Injection Volume for A/F sensor operation with the engine idling (press the RIGHT or LEFT button to change the fuel injection volume).

(f) 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.

HINT
- The Control the Injection Volume for A/F sensor operation lowers the fuel injection volume by +12.5% or increases the injection volume by -12.5%.
- Each sensor reacts in accordance with increases and decreases in the fuel injection volume.

Standard:





Result:





Lean: During Control the Injection Volume for A/F sensor, the A/F sensor output voltage (AFS) is consistently more than 3.4 V, and the HO2 sensor output voltage (O2S) is consistently less than 0.4 V.
Rich: During Control the Injection Volume for A/F sensor, the AFS is consistently less than 3.1 V, and the O2S is consistently more than 0.55 V.
Lean/Rich: During Control the Injection Volume for A/F sensor of the Active Test, the output voltage of the HO2 sensor alternates correctly.

B -- CHECK AND REPLACE AIR FUEL RATIO SENSOR

C -- CHECK AND REPLACE HEATED OXYGEN SENSOR, AND CHECK AND REPAIR EXHAUST GAS LEAKAGE
A -- Continue to next step.

3. CHECK FOR EXHAUST GAS LEAK

OK:

No gas leakage.

NG -- REPAIR OR REPLACE EXHAUST GAS LEAKAGE POINT
OK -- Continue to next step.

4. CHECK DTC OUTPUT (DTC P0420 AND/OR P0430)

(a) According to the output DTCs in the step 1 (Check Any Other DTCs Output), proceed to next step referring to the table below.

Result:





A -- REPLACE EXHAUST MANIFOLD SUB-ASSEMBLY LH (2WD) (TWC: FRONT CATALYST) Removal

B -- REPLACE EXHAUST MANIFOLD SUB-ASSEMBLY LH (AWD) (TWC: FRONT CATALYST) Removal

C -- REPLACE EXHAUST MANIFOLD SUB-ASSEMBLY RH (2WD) (TWC: FRONT CATALYST) Removal

D -- REPLACE EXHAUST MANIFOLD SUB-ASSEMBLY RH (AWD) (TWC: FRONT CATALYST) Removal

E -- REPLACE FRONT EXHAUST PIPE ASSEMBLY (TWC: REAR CATALYST) Removal
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