Inspection Procedure
HINT:
Intelligent tester only:
Malfunctioning areas can be identified by performing the A/F CONTROL function provided in the ACTIVE TEST. The A/F CONTROL 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 A/F CONTROL operation using an intelligent tester.
- Connect an intelligent tester to the DLC3.
- Start the engine and turn the tester ON.
- Warm up the engine at an engine speed of 2,500 rpm for approximately 90 seconds.
- Select the following menu items: DIAGNOSIS / ENHANCED OBD II ACTIVE TEST / A/F CONTROL.
- Perform the A/F CONTROL 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 B1S1 and O2S B1S2 or AFS B2S1 and O2S B2S2) displayed on the tester.
HINT:
- The A/F CONTROL operation lowers the fuel injection volume by 12.5% or increases the injection volume by 25%.
- Each sensor reacts in accordance with increases and decreases in the fuel injection volume.
Standard
INJECTION VOLUMES AND STATUSTester Display (Sensor) Injection Volumes Status Voltages AFS B1S1 or AFS B2S1 (A/F) +25% Rich Less than 3.0 AFS B1S1 or AFS B2S1 (A/F) -12.5% Lean More than 3.35 O2S B1S2 or O2S B2S2 (HO2) +25% Rich More than 0.55 O2S B1S2 or O2S B2S2 (HO2) -12.5% Lean Less than 0.4
| Case | A/F Sensor (Sensor 1) Output Voltage | HO2 Sensor (Sensor 2) Output Voltage | Main Suspected Trouble Areas | ||
|---|---|---|---|---|---|
| 1 | Injection Volume +25% -12.5% |
Injection Volume +25% -12.5% |
- | ||
| Output Voltage More than 3.35 V Less than 3.0 V |
Output Voltage More than 0.55 V Less than 0.4 V |
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| 2 | Injection Volume +25% -12.5% |
Injection Volume +25% -12.5% |
|
||
| Output Voltage Almost no reaction |
Output Voltage More than 0.55 V Less than 0.4 V |
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| 3 | Injection Volume +25% -12.5% |
Injection Volume +25% -12.5% |
|
||
| Output Voltage More than 3.35 V Less than 3.0 V |
Output Voltage Almost no reaction |
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| 4 | Injection volume +25% -12.5% |
Injection Volume +25% -12.5% |
|
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| Output Voltage Almost no reaction |
Output Voltage Almost no reaction |
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- Following the A/F CONTROL procedure enables technicians to check and graph the voltage outputs of both the A/F and HO2 sensors.
- To display the graph, select the following menu items on the tester: DIAGNOSIS / ENHANCED OBD II / ACTIVE TEST / A/F CONTROL / USER DATA / AFS B1S1 and O2S B1S2 or AFS B2S1 and O2S B2S2, and press the YES button and then the ENTER button followed by the F4 button.
HINT:
Read freeze frame data using an intelligent tester. Freeze frame data record 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.
- CHECK ANY OTHER DTCS OUTPUT (IN ADDITION TO DTC P0420 AND/OR P0430)
- Connect an intelligent tester to the DLC3.
- Turn the ignition switch ON and turn the tester ON.
- Select the following menu items: DIAGNOSIS / ENHANCED OBD II / DTC INFO / CURRENT CODES.
- Read DTCs.
Result
DTC RESULT DESCRIPTIONDisplay (DTC Output) Proceed To P0420 and/or P0430 A P0420 and/or P0430 and other DTCs B HINT:
If any DTCs other than P0420 or P0430 are output, troubleshoot those DTCs first.
B: GO TO DIAGNOSTIC TROUBLE CODE TABLE
A: Go TO NEXT STEP
- PERFORM ACTIVE TEST USING INTELLIGENT TESTER (A/F CONTROL)
- Connect an intelligent tester to the DLC3.
- Start the engine and turn the tester ON.
- Warm up the engine at an engine speed of 2,500 rpm for approximately 90 seconds.
- Select the following menu items: DIAGNOSIS / ENHANCED OBD II / ACTIVE TEST/ A/F CONTROL.
- Perform the A/F CONTROL 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 B1S1 and O2S B1S2 or AFS B2S1 and O2S B2S2) displayed on the tester.
HINT:
- The A/F CONTROL operation lowers the fuel injection volume by 12.5% or increases the injection volume by 25%.
- Each sensor reacts in accordance with increases and decreases in the fuel injection volume.
Standard
INJECTION VOLUMES AND STATUSTester Display (Sensor) Injection Volumes Status Voltages AFS B1S1 or AFS B2S1 (A/F) +25% Rich Less than 3.0 AFS B1S1 or AFS B2S1 (A/F) -12.5% Lean More than 3.35 O2S B1S2 or O2S B2S2 (HO2) +25% Rich More than 0.55 O2S B1S2 or O2S B2S2 (HO2) -12.5% Lean Less than 0.4 Result
DTC RESULT DESCRIPTIONStatus AFS B1S1 or AFS B2S1 Status O2S B1S2 or O2S B2S2 A/F Condition and A/F and HO2 Sensors Conditions Misfires Main Suspected Trouble Areas Proceed To Lean/Rich Lean/Rich Normal - - Three-Way Catalytic Converter (TWC)
- Gas leakage from exhaust system
A Lean Lean/Rich A/F sensor malfunction - - A/F sensor
B Rich Lean/Rich A/F sensor malfunction - - A/F sensor
Lean/Rich Lean HO2 sensor malfunction - - HO2 sensor
- Gas leakage from exhaust system
C Lean/Rich Rich HO2 sensor malfunction - - HO2 sensor
- Gas leakage from exhaust system
Lean Lean Actual air-fuel ratio lean May occur - Extremely rich or lean actual air-fuel ratio
- Gas leakage from exhaust system
A Rich Rich Actual air-fuel ratio rich - - Extremely rich or lean actual air-fuel ratio
- Gas leakage from exhaust system
Lean: During A/F CONTROL, the A/F sensor output voltage (AFS) is consistently more than 3.35 V, and the HO2 sensor output voltage (O2S) is consistently less than 0.4 V.
Rich: During A/F CONTROL, the AFS is consistently less than 3.0 V, and the O2S is consistently more than 0.55 V.
Lean/Rich: During A/F CONTROL 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: Go TO NEXT STEP
- CHECK FOR EXHAUST GAS LEAKAGE
OK:
No gas leakage.
NG: REPAIR OR REPLACE EXHAUST GAS LEAKAGE POINT
OK: REPLACE THREE-WAY CATALYTIC CONVERTER