DTC P2A00 A/F Sensor Circuit Slow Response (Bank 1 Sensor 1): Wiring Diagram
Refer to DTC P2195 ).
HINT:
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.
- 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 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 in the fuel injection volume.
Standard:
VOLTAGE REFERENCE CHART
| Tester Display (Sensor) | Injection Volume | Status | Voltage |
|---|---|---|---|
| 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 |
NOTE:
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.
DIAGNOSIS PROCEDURE
| 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 |
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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 |
||||
| 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 |
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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, enter the following menus: 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:
- DTC P2A00 may be also set when the air-fuel ratio is stuck at 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 conditions when malfunctions are 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.
- 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.
- Enter the following menus: DIAGNOSIS / ENHANCED OBD II / DTC INFO / CURRENT CODES.
- Read DTCs.
Result
RESULT CHARTDisplay (DTC Output) Proceed to P2A00 A P2A00 and other DTCs B HINT:
If any DTCs other than P2A00 are output, troubleshoot those DTCs first.
B : GO TO DTC CHART
A : Go to next step
- READ VALUE USING INTELLIGENT TESTER (OUTPUT VOLTAGE OF A/F SENSOR)
- Connect the intelligent tester to the DLC3.
- Start the engine.
- Turn the tester ON.
- Warm up the Air-Fuel Ratio (A/F) sensor at an engine speed of 2,500 rpm for 90 seconds.
- Enter the following menus: DIAGNOSIS / ENHANCED OBD II / SNAPSHOT / MANUAL SNAPSHOT / USER DATA / AFS B1S1 and ENGINE SPD.
- Check the A/F sensor voltage 3 times, when the engine is in each of the following conditions:
- While idling (check for at least 30 seconds)
- At an engine speed of approximately 2,500 rpm (without any sudden changes in engine speed)
- Raise the engine speed to 4,000 rpm and then quickly release the accelerator pedal so that the throttle valve is fully closed.
Standard voltage
VOLTAGE REFERENCE CHARTConditions A/F Sensor Voltage Variations Reference (1) and (2) Changes at approximately 3.3 V Between 3.1 V and 3.5 V (3) Increases to 3.8 V or more This occurs during engine deceleration (when fuel-cut performed) For more information, see the diagrams below.
HINT:
- If the output voltage of the A/F sensor remains at approximately 3.3 V (see ) under any conditions, including those above, the A/F sensor may have an open circuit. (This will also happen if the A/F sensor heater has an open circuit.)
- If the output voltage of the A/F sensor remains at either approximately 3.8 V or more, or 2.8 V or less (see ) under any conditions, including those above, the A/F sensor may have a short circuit.
- The ECM stops fuel injection (fuel cut) during engine deceleration. This causes a lean condition and results in a momentary increase in the A/F sensor output voltage.
- The ECM must establish a closed throttle valve position learning value to perform fuel cut. If the battery terminal has been reconnected, the vehicle must be driven over 16 km/h (10 mph) to allow the ECM to learn the closed throttle valve position.
- When the vehicle is driven:
The output voltage of the A/F sensor may be below 2.8 V during fuel enrichment. For the vehicle, this translates to a sudden increase in speed with the accelerator pedal fully depressed when trying to overtake another vehicle. The A/F sensor is functioning normally.
- The A/F sensor is a current output element; therefore, the current is converted into a voltage inside the ECM. Measuring the voltage at the connectors of the A/F sensor or ECM will show a constant voltage result.
NG : GO TO STEP 9
OK : Go to next Step
- PERFORM CONFIRMATION DRIVING PATTERN
NEXT
- CHECK WHETHER DTC OUTPUT RECURS (DTC P2A00)
- Read DTCs using the intelligent tester.
- Enter the following menus: DIAGNOSIS / ENHANCED OBD II / DTC INFO / CURRENT CODES.
Result
RESULT CHARTDisplay (DTC Output) Proceed to P2A00 A No output B B : GO TO STEP 8
A : Go to next step
- REPLACE AIR FUEL RATIO SENSOR
NEXT
- PERFORM CONFIRMATION DRIVING PATTERN
NEXT
- CHECK WHETHER DTC OUTPUT RECURS (DTC P2A00)
- Read DTCs using the intelligent tester.
- Enter the following menus: DIAGNOSIS / ENHANCED OBD II / DTC INFO / CURRENT CODES.
Result
RESULT CHARTDisplay (DTC Output) Proceed to No output A P2A00 B B : REPLACE ECM AND PERFORM CONFIRMATION DRIVING PATTERN
A : Go to next step
- CONFIRM WHETHER VEHICLE HAS RUN OUT OF FUEL IN PAST
NO : CHECK FOR INTERMITTENT PROBLEMS
YES : DTC CAUSED BY RUNNING OUT OF FUEL
- INSPECT AIR FUEL RATIO SENSOR (HEATER RESISTANCE)
- Disconnect the A3 A/F sensor connector.
- Measure the resistance of the sensor connector.
Standard resistance
TESTER CONNECTION SPECIFIED CONDITION CHARTTester Connection Specified Condition HT (1) - +B (2) 1.8 to 3.4 Ω at 20°C (68°F) HT (1) - AF- (4) 10 kΩ or higher NG : REPLACE AIR FUEL RATIO SENSOR
OK : Go to next Step
- INSPECT EFI RELAY (Marking: EFI)
- Remove the EFI relay from the engine room relay block.
- Measure the resistance of the EFI relay.
Standard
TESTER CONNECTION SPECIFIED CONDITION CHARTTester Connection Specified Condition 3 - 5 10 kΩ or higher 3 - 5 Below 1 Ω (when battery voltage is applied to terminals 1 and 2) NG : REPLACE EFI RELAY
OK : Go to next Step
- CHECK WIRE HARNESS (A/F SENSOR -ECM) AND (SENSOR POWER SOURCE)
- Disconnect the A3 A/F sensor connector.
- Turn the ignition switch ON.
- Measure the voltage of the wire harness side connectors.
Standard voltage
TESTER CONNECTION SPECIFIED CONDITION CHARTTester Connection Specified Condition +B (A3-2) - Body ground 9 to 14 V - Turn the ignition switch OFF.
- Disconnect the E7 ECM connector.
- Measure the resistance of the wire harness side connectors.
Standard resistance
TESTER CONNECTION SPECIFIED CONDITION CHARTTester Connection Specified Condition HT (A3-1) - HA1A (E7-5) Below 1 Ω AF+ (A3-3) - A1A+ (E7-23) Below 1 Ω AF- (A3-4) - A1A- (E7-31) Below 1 Ω HT (A3-1) or HA1A (E7-5) - Body ground 10 kΩ or higher AF+ (A3-3) or A1A+ (E7-23) - Body ground 10 kΩ or higher AF- (A3-4) or A1A- (E7-31) - Body ground 10 kΩ or higher NG : REPAIR OR REPLACE HARNESS OR CONNECTOR
OK : Go to next Step
- CHECK AIR INDUCTION SYSTEM
- Check the air induction system for vacuum leakage.
OK:
No leakage from air induction system.
NG : REPAIR OR REPLACE AIR INDUCTION SYSTEM
OK : Go to next Step
- CHECK PCV HOSE CONNECTIONS
OK:
PCV hose is connected correctly and is not damaged.
NG : REPAIR OR REPLACE PCV HOSE
OK : Go to next Step
- CHECK FUEL PRESSURE
- Check the fuel pressure.
NG : REPAIR OR REPLACE FUEL SYSTEM
OK : Go to next Step
- INSPECT FUEL INJECTOR
- Check the injector injection (whether fuel volume is high or low, and whether injection pattern is poor).
NG : REPLACE FUEL INJECTOR
OK : Go to next Step
- REPLACE AIR FUEL RATIO SENSOR
NEXT
- PERFORM CONFIRMATION DRIVING PATTERN
NEXT
- CHECK WHETHER DTC OUTPUT RECURS (DTC P2A00)
- Read DTCs using the intelligent tester.
- Enter the following menus: DIAGNOSIS / ENHANCED OBD II / DTC INFO / CURRENT CODES.
Result
RESULT CHARTDisplay (DTC Output) Proceed to No output A P2A00 B B : REPLACE ECM AND PERFORM CONFIRMATION DRIVING PATTERN
A : Go to next step
- CONFIRM WHETHER VEHICLE HAS RUN OUT OF FUEL IN PAST
NO : CHECK FOR INTERMITTENT PROBLEMS
YES : DTC CAUSED BY RUNNING OUT OF FUEL