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 the intelligent tester.
- Connect the 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.
- On the tester, select the following menu items: DIAGNOSIS / ENHANCED OBD II / ACTIVE TEST / A/F CONTROL.
- Perform the A/F CONTROL operation with the engine idling (press the RIGHT or LEFT button to change the fuel injection volume).
- Monitor the voltage outputs of the A/F and HO2 sensors (AFS B1 S1 and O2S B1 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 %.
- The sensors react in accordance with increases and decreases in the fuel injection volume.
Standard
| Tester Display (Sensor) | Injection Volumes | Status | Voltages |
|---|---|---|---|
| AFS B1 S1 (A/F) | +25 % | Rich | Less than 3.0 |
| -12.5 % | Lean | More than 3.35 | |
| O2S B1 S2 (HO2) | +25 % | Rich | More than 0.5 |
| -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 0.5 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 0.5 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 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 B1 S1 and O2S B1 S2; and press the YES button and then the ENTER button followed by the F4 button.
HINT:
- DTC P2A00 may be set when the air-fuel ratio is stuck rich or lean.
- A low A/F sensor voltage could be caused by a rich air-fuel mixture. Check for conditions that would cause the engine to run rich.
- A high A/F sensor voltage could be caused by a lean air-fuel mixture. Check for conditions that would cause the engine to run lean.
- Read freeze frame data using the intelligent tester. 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.
- CHECK ANY OTHER DTCS OUTPUT (IN ADDITION TO DTC P2A00)
- Connect the intelligent tester to the DLC3.
- Turn the ignition switch ON.
- Turn the tester ON.
- Select the following menu items: DIAGNOSIS / ENHANCED OBD II / DTC INFO / CURRENT CODES.
- Read DTCs.
Result
RESULTDisplay (DTC Output) Proceed To P2A00 A P2A00 and other DTCs B If any DTCs relating to the A/F sensor (DTCs for the A/F sensor heater or A/F sensor admittance) are output, troubleshoot those DTCs first.
B: GO TO DTC CHART
A: Go TO NEXT STEP.
- INSPECT AIR-FUEL RATIO SENSOR (HEATER RESISTANCE) (See COMPONENT OPERATING RANGE
)
NG: REPLACE AIR-FUEL RATIO SENSOR
OK: Go TO NEXT STEP.
- CHECK HARNESS AND CONNECTOR (ECM - AIR-FUEL RATIO SENSOR) (See DTC P2238 Oxygen (A/F) Sensor Pumping Current Circuit Low (Bank 1 Sensor 1); DTC P2239 Oxygen (A/F) Sensor Pumping Current Circuit High (Bank 1 Sensor 1); DTC P2252 Oxygen (A/F) Sensor Reference Ground Circuit Low (Bank 1 Sensor 1); DTC P2253 Oxygen (A/F) Sensor Reference Ground Circuit High (Bank 1 Sensor 1)
)
NG: REPAIR OR REPLACE HARNESS OR CONNECTOR
OK: Go TO NEXT STEP.
- PERFORM CONFIRMATION DRIVING PATTERN
- CHECK WHETHER DTC OUTPUT RECURS (DTC P2A00)
- Connect the 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 / PENDING CODES.
- Read pending DTCs.
Result
RESULTDisplay (DTC Output) Proceed To P2A00 A No output B
B: CHECK FOR INTERMITTENT PROBLEMS
A: Go TO NEXT STEP.
- REPLACE AIR-FUEL RATIO SENSOR
- PERFORM CONFIRMATION DRIVING PATTERN
- CHECK WHETHER DTC OUTPUT RECURS (DTC P2A00)
- Connect the 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 / PENDING CODES.
- Read pending DTCs.
Result
RESULTDisplay (DTC Output) Proceed To No output A P2A00 B
B: REPLACE ECM
A: END