Conditioning For Sensor Testing
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 performed in order to heat the sensors sufficiently to obtain the appropriate inspection results.
- Connect the intelligent tester to the DLC3 (Procedure "A").
- Start the engine and warm it up with all the accessories switched OFF, until the engine coolant temperature stabilizes (Procedure "B").
- Run the engine at engine speed of between 2, 500 rpm and 3, 000 rpm for at least 3 minutes (Procedure "C").
- While running the engine at 3, 000 rpm for 2 seconds and 2, 000 rpm for 2 seconds, check the waveforms of the A/F and HO2 sensors using the tester or scan tool (Procedure "D").
| Case | A/F Sensor (Sensor 1) Output Voltage | HO2 Sensor (Sensor 2) Output Voltage | Main Suspected Trouble Area | ||
|---|---|---|---|---|---|
| 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 | ||||
| 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 | ||||
| 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 | ||||
| 4 | Injection volume +25 % -12.5 % | Injection Volume +25 % -12.5 % |
|
||
| Output Voltage Almost no reaction | Output Voltage Almost no reaction | ||||
- Following the A/F CONTROL procedure enables technicians to check and graph the output voltages of both the A/F and HO2 sensors.
- To display the graph, enter the following menus on the tester: DIAGNOSIS / ENHANCED OBD II / ACTIVE TEST / A/F CONTROL / USER DATA / AFS B1 S1 and O2S B1 S2 or AFS B2 S1 and O2S B2 S2, and press the YES button and then the ENTER button followed by the F4 button.
HINT:
Read freeze frame data using the intelligent tester. The ECM records vehicle and driving condition information as freeze frame data the moment a DTC is stored. When troubleshooting, freeze frame data can be helpful in determining whether the vehicle was running or stopped, whether the engine was warmed up or not, whether the air/fuel ratio was lean or rich, as well as other data recorded at the time of a malfunction (See FREEZE FRAME DATA ).
- CHECK ANY OTHER DTCS OUTPUT (IN ADDITION TO DTC P0420 AND/OR P0430)
- Connect the intelligent tester 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 DTCs.
Result
RESULT CHARTDisplay (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 DTC CHART
A : Go To Next Step
- PERFORM ACTIVE TEST BY INTELLIGENT TESTER (A/F CONTROL)
- Connect the intelligent tester to the DLC3.
- Start the engine and turn the tester on.
- Warm up the engine at engine speed of 2, 500 rpm for approximately 90 seconds.
- On the tester, enter the following menus: 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 output voltages of the A/F and HO2 sensors (AFS B1 S1 and O2S B1 S2 or AFS B2 S1 and O2S B2 S2) 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.
INTELLIGENT TESTER DIAGNOSIS PROCEDURETester Display (Sensor) Injection Volume Status Voltage AFS B1 S1 or AFS B2 S1 (A/F) +25 % Rich Less than 3.0 V AFS B1 S1 or AFS B2 S1 (A/F) -12.5 % Lean More than 3.35 V O2S B1 S2 or O2S B2 S2 (HO2) +25 % Rich More than 0.55 V O2S B1 S2 or O2S B2 S2 (HO2) -12.5 % Lean Less than 0.4 V Result
RESULT CHARTStatus AFS B1 S1 or AFS B2 S1 Status O2S B1 S2 or O2S B2 S2 A/F Condition and A/F and HO2 Sensor Conditions Misfire 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 May occur - A/F sensor
B 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
C 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 lean - - Extremely rich or lean actual air-fuel ratio
- Gas leakage from exhaust system
A Lean:
During A/F CONTROL, the A/F sensor (AFS) output voltage 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