P2A00
DTC P2A00 A/F Sensor Circuit Slow Response (Bank 1 Sensor 1)DTC P2A03 A/F Sensor Circuit Slow Response (Bank 2 Sensor 1)
DTC Detection Condition:
DESCRIPTION
- DTC P2A00 indicates malfunctions related to the bank 1 A/F sensor.
- DTC P2A03 indicates malfunctions related to the bank 2 A/F sensor.
- Bank 1 refers to the bank that includes No. 1 cylinder.
- Bank 2 refers to the bank that includes No. 2 cylinder.
- Sensor 1 refers to the sensor mounted in front of the Three-Way Catalytic Converter (TWC) and is located near the engine assembly.
HINT:
- Although the DTC titles refer to the "oxygen sensor", these DTCs relate to the Air Fuel Ratio (A/F) sensor.
- Sensor 1 refers to the sensor mounted in front of the Three-Way Catalytic Converter (TWC) and located near the engine assembly.
The A/F sensor generates voltage* that corresponds to the actual air fuel ratio. This sensor voltage is used to provide the ECM with feedback so that it can control the air fuel ratio. The ECM determines the deviation from the stoichiometric air fuel ratio level, and regulates the fuel injection time. If the A/F sensor malfunctions, the ECM is unable to control the air fuel ratio accurately.
The A/F sensor is the planar type and is integrated with the heater, which heats the solid electrolyte (zirconia element). This heater is controlled by the ECM. When the intake air volume is low (the exhaust gas temperature is low), a current flows into the heater to heat the sensor, in order to facilitate accurate oxygen concentration detection. In addition, the sensor and heater portions are narrower than the conventional type. The heat generated by the heater is conducted to the solid electrolyte through the alumina, and the sensor activation is accelerated.
In order to obtain a high purification rate of the carbon monoxide (CO), hydrocarbon (HC) and nitrogen oxide (NOx) components in the exhaust gas, a TWC is used. For the most efficient use of the TWC, the air fuel ratio must be precisely controlled so that it is always close to the stoichiometric level.
MONITOR DESCRIPTION
Monitor Strategy:
Typical Enabling Conditions:
Typical Malfunction Thresholds:
After engine is warmed up, the ECM performs air fuel ratio feedback control to regulate the air fuel ratio at stoichiometric ratio. In addition, this vehicle performs Active Air Fuel Ratio (A/F) Control for approximately 10 seconds after preconditions are met in order to measure the A/F sensor response rate. During active air fuel ratio control, the ECM forcibly increases and decreases the injection volume a certain amount based on learned stoichiometric air fuel ratio during usual air fuel feedback control, and measures the A/F sensor response rate. The ECM receives a signal from the A/F sensor while performing active A/F control and uses it to calculate the A/F sensor response rate deterioration level.
If the test value for A/F sensor response rate deterioration level is less than the threshold, the ECM interprets this as a malfunction, and sets the DTC.
MONITOR RESULT
Detailed information on Checking Monitor Status. Mode 6 Data
The test value and test limit information are described as shown in the following table. Check the monitor result and test values after performing the monitor drive pattern (refer to "Confirmation Monitor").
- MID (Monitor Identification Data) is assigned to each emissions-related component.
- TID (Test Identification Data) is assigned to each test value.
- Scaling is used to calculate the test value indicated on generic OBD II scan tools.
CONFIRMATION DRIVING PATTERN
HINT: Performing this confirmation pattern will activate the air fuel ratio (A/F) sensor response monitor.
1. Connect the intelligent tester to the DLC3 with CAN VIM [A].
2. Turn the ignition switch ON [B].
3. Turn the tester ON [C].
4. Clear DTCs (if set) [D].
5. Enter the following menus: DIAGNOSIS / ENHANCED OBD II / MONITOR INFO / MONITOR RESULT [E].
6. Check that RES RATE B1 S1 is INCOMPL [F].
7. Start the engine and warm it up [G].
8. Drive the vehicle at between 25 mp and 75 mph (40 km/h and 120 km/h) for 3 minutes. However, the vehicle should be driven at a constant speed [H].
9. Check the monitor result values on the intelligent tester by entering the following menus: DIAGNOSIS / ENHANCED OBD II / MONITOR INFO / TEST RESULT [I].
10. If the values indicated on the tester do not change, perform READINESS MONITOR DRIVE PATTERN for the A/F sensor and the heated oxygen sensor [J].
HINT: Completion of all A/F sensor monitors are required to change the value in TEST RESULT.
11. Note the value of the Monitor Result [K].
12. Enter the following menus: DIAGNOSIS / ENHANCED OBD II / DTC INO / PENDING CODES [L].
13. Check if any pending DTCs are set [M].
Wiring Diagram:
Step 1:
Step 1(Continued)-3:
Step 3(Continued)-5:
Step 5(Continued)-8:
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.
1. Connect the intelligent tester to the DLC3 with CAN VIM.
2. Start the engine and turn the tester ON.
3. Warm up the engine at an engine speed of 2,500 rpm for approximately 90 seconds.
4. On the intelligent tester, enter the following menus: DIAGNOSIS / ENHANCED OBD II / ACTIVE TEST / A/F CONTROL.
5. 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).
6. Monitor the output voltages of the A/F and HO2 sensors (AFS B1S1 (AFS B2S1) and O2S B1S2 (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.
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.
- 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. Then press the YES button and ENTER button, followed by the F4 button.
HINT:
- DTC P2A00 may be also 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. 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.