P2A00
2UR-FSE ENGINE CONTROL SYSTEM: SFI SYSTEM: P2A00,P2A03: A/F Sensor Circuit Slow Response (Bank 1 Sensor 1)
P2A03 - A/F Sensor Circuit Slow Response (Bank 2 Sensor 1)
DESCRIPTION
Refer to DTC P2195 P2195.
HINT
- 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 located near the engine assembly.
MONITOR DESCRIPTION
After engine is warmed up, the ECM performs air-fuel ratio feedback control to maintain the air-fuel ratio at the stoichiometric level. In addition, active A/F control is performed for approximately 10 seconds after preconditions are met in order to measure the A/F sensor response rate. During active A/F control, the ECM forcibly increases and decreases the injection volume a certain amount, based on the stoichiometric air-fuel ratio learned during normal air-fuel ratio 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 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 STRATEGY
TYPICAL ENABLING CONDITIONS
TYPICAL MALFUNCTION THRESHOLDS
MONITOR RESULT
Refer to CHECKING MONITOR STATUS Mode 6 Data.
WIRING DIAGRAM
Refer to DTC P2195 P2195.
CONFIRMATION DRIVING PATTERN
HINT
This confirmation driving pattern is used in the "PERFORM CONFIRMATION DRIVING PATTERN" procedure of the following diagnostic troubleshooting procedure.
NOTICE:
This test will not be completed if the vehicle is driven under absolutely constant speed conditions such as with cruise control activated.
1. Connect the Techstream to the DLC3.
2. Turn the power switch on (READY).
3. Clear DTCs DTC Check / Clear.
4. Warm-up the engine until the engine coolant temperature is 75°C (167°F) or more.
5. Drive the vehicle at between 70 km/h and 120 km/h (45 mph and 75 mph) for at least 10 minutes or more.
6. Stop the vehicle.
7. Turn the Techstream ON.
8. Enter the following menus: Powertrain / Engine and ECT / Utility / All Readiness.
9. Input DTCs: P2A00 and P2A03.
10. Check that DTC MONITOR is NORMAL. If DTC MONITOR is INCOMPLETE, perform the drive pattern by increasing the vehicle speed and using the S2 range to decelerate the vehicle.
INSPECTION PROCEDURE
HINT
Malfunctioning areas can be identified by performing the Control the Injection Volume for A/F sensor function provided in the Active Test. The Control the Injection Volume for A/F sensor 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 Control the Injection Volume for A/F sensor operation using the Techstream.
(a) Connect the Techstream to the DLC3.
(b) Put the engine in inspection mode Inspection Mode Procedure.
(c) Turn the Techstream ON.
(d) Warm up the engine at an engine speed of 2500 rpm for approximately 90 seconds.
(e) On the Techstream, enter the following menus: Powertrain / Engine and ECT / Active Test / Control the Injection Volume for A/F sensor.
(f) Perform the Active Test operation with the engine in an idling condition (press the RIGHT or LEFT button to change the fuel injection volume).
(g) Monitor the output voltages of the A/F and HO2 sensors (AFS Voltage B1S1 and O2S B1S2 or AFS Voltage B2S1 and O2S B2S2) displayed on the Techstream.
HINT
- The Control the Injection Volume for A/F sensor 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.
NOTICE:
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 Control the Injection Volume for A/F sensor 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: Powertrain / Engine and ECT / Active Test / Control the Injection Volume for A/F Sensor / A/F Control System / AFS Voltage B1S1 and O2S B1S2 or AFS Voltage B2S1 and O2S B2S2.
HINT
- When viewed from the rear of the engine assembly, Bank 1 is on the left side and Bank 2 is on the right side.
- DTC P2A00 or P2A03 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 Techstream. 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.
PROCEDURE
1. CHECK ANY OTHER DTCS OUTPUT (IN ADDITION TO DTC P2A00 AND/OR P2A03)
(a) Connect the Techstream to the DLC3.
(b) Turn the power switch on (IG).
(c) Turn the Techstream ON.
(d) Enter the following menus: Powertrain / Engine and ECT / Trouble Codes.
(e) Read DTCs.
Result
HINT
If any DTCs other than P2A00 or P2A03 are output, troubleshoot those DTCs first.
B -- GO TO DTC CHART SFI System
A -- Continue to next step.
2. INSPECT AIR FUEL RATIO SENSOR (HEATER RESISTANCE) P0031
NG -- REPLACE AIR FUEL RATIO SENSOR Removal
OK -- Continue to next step.
3. CHECK HARNESS AND CONNECTOR (A/F SENSOR - ECM) P0171
NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR
OK -- Continue to next step.
4. PERFORM CONFIRMATION DRIVING PATTERN
NEXT -- Continue to next step.
5. CHECK WHETHER DTC OUTPUT RECURS (DTC P2A00 AND/OR P2A03)
(a) Connect the Techstream to the DLC3.
(b) Turn the power switch on (IG) and turn the Techstream ON.
(c) Enter the following menus: Powertrain / Engine and ECT / Trouble Codes / Pending.
(d) Read DTCs.
Result
B -- CHECK FOR INTERMITTENT PROBLEMS Check For Intermittent Problems
A -- Continue to next step.
6. REPLACE AIR FUEL RATIO SENSOR
(a) Replace the air fuel ratio sensor Removal.
NEXT -- Continue to next step.
7. PERFORM CONFIRMATION DRIVING PATTERN
NEXT -- Continue to next step.
8. CHECK WHETHER DTC OUTPUT RECURS (DTC P2A00 AND/OR P2A03)
(a) Connect the Techstream to the DLC3.
(b) Turn the power switch on (IG) and turn the Techstream ON.
(c) Enter the following menus: Powertrain / Engine and ECT / Trouble Codes / Pending.
(d) Read DTCs.
Result
B -- CHECK EXTREMELY RICH OR LEAN ACTUAL AIR FUEL RATIO (REFER TO DTC P0171 PROCEDURE) P0171
A -- END