P2A00
2GR-FE ENGINE CONTROL SYSTEM: SFI SYSTEM: P2A00,P2A03: A/F Sensor Circuit Slow Response (Bank 1 Sensor 1)
DTC P2A00 - A/F Sensor Circuit Slow Response (Bank 1 Sensor 1)
DTC P2A03 - A/F Sensor Circuit Slow Response (Bank 2 Sensor 1)
CAUTION / NOTICE / HINT
HINT:
- DTC P2A00 indicates malfunctions related to the bank 1 air fuel ratio sensor.
- DTC P2A03 indicates malfunctions related to the bank 2 air fuel ratio sensor.
- Bank 1 refers to the bank that includes cylinder No. 1.
- Bank 2 refers to the bank that includes cylinder No. 2.
- Sensor 1 refers to the sensor mounted in front of the three-way catalytic converter and located near the engine assembly.
DESCRIPTION
HINT:
- Although the DTC titles say oxygen sensor, these DTCs relate to the air fuel ratio sensor.
- Sensor 1 refers to the sensor mounted in front of the three-way catalytic converter and located near the engine assembly.
The air fuel ratio sensor generates a 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 air fuel ratio sensor malfunctions, the ECM is unable to control the air fuel ratio accurately.
The air fuel ratio 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, therefore the sensor activation is accelerated.
A three-way catalytic converter is used in order to convert the carbon monoxide (CO), hydrocarbon, and nitrogen oxides (HOx) into less harmful substances. To allow the three-way catalytic converter to function effectively, it is necessary to keep the air fuel ratio of the engine near the stoichiometric air fuel ratio.
*: Value changes inside the ECM. Since the air fuel ratio sensor is the current output element, a current is converted to a voltage inside the ECM. Any measurements taken at the air fuel ratio sensor or ECM connectors will show a constant voltage.
HINT:
- When any of these DTCs are set, check the air fuel ratio sensor voltage output by selecting the following menu items on the Techstream: Powertrain / Engine and ECT / Data List / A/F Control System / AFS Voltage B1 S1 or AFS Voltage B2 S1.
- Short-term fuel trim values can also be read using the Techstream.
- The ECM regulates the voltages at the A1A+, A2A+, A1A- and A2A- terminals of the ECM to a constant level. Therefore, the air fuel ratio sensor voltage output cannot be confirmed without using the Techstream.
- If an air fuel ratio sensor malfunction is detected, the ECM sets a DTC.
MONITOR DESCRIPTION
After the 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 air fuel ratio ratio control is performed for approximately 10 seconds after preconditions are met in order to measure the air fuel ratio sensor response rate. During active air fuel ratio ratio control, the ECM forcibly increases and decreases the injection volume to a certain amount, based on the stoichiometric air fuel ratio learned during normal air fuel ratio control, and measures the air fuel ratio sensor response rate. The ECM receives a signal from the air fuel ratio sensor while performing active air fuel ratio ratio control and uses it to calculate the air fuel ratio sensor response rate deterioration level.
If the value for air fuel ratio sensor response rate deterioration level is less than the threshold, the ECM interprets this as a malfunction and sets the DTC.
CONFIRMATION DRIVING PATTERN
HINT: Performing this confirmation driving pattern will activate the air fuel ratio sensor response monitor.
1. Connect the Techstream to the DLC3.
2. Turn the ignition switch on (IG).
3. Turn the tester on.
4. Clear the DTCs (where set).
5. Select the following menu items: Powertrain / Engine and ECT / Monitor / O2 Sensor / Details.
6. Check that RES RATE B1S1 and RES RATE B2S1 are Incomplete.
7. Start the engine and warm it up (Procedure "A").
8. Drive the vehicle at between 25 mph and 75 mph (40 km/h and 120 km/h) for 3 minutes. However, the vehicle should be driven at a constant speed (Procedure "B").
9. Check the monitor result values on the Techstream by selecting the following menu items: Powertrain / Engine and ECT / Monitor / O2 Sensor / Details / RES RATE B1S1 and RES RATE B2S1.
10. If the values indicated on the tester do not change, perform READINESS MONITOR DRIVE PATTERN for the air fuel ratio sensor and the heated oxygen sensor Monitors, Trips, Drive Cycles and Readiness Codes.
HINT: Completion of all air fuel ratio sensor monitors is required to change the value in test result.
11. Note the value of the Monitor Result.
12. Select the following menu items: Powertrain / Engine and ECT / Trouble Code / Pending.
13. Check if any DTCs (any pending DTCs) are set.
MONITOR STRATEGY
TYPICAL ENABLING CONDITIONS
TYPICAL MALFUNCTION THRESHOLDS
MONITOR RESULT
Refer to CHECKING MONITOR STATUS Mode 6 Data.
WIRING DIAGRAM
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 sensor, heated oxygen 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.
1. Connect the Techstream to the DLC3.
2. Start the engine and turn the tester on.
3. Warm up the engine at an engine speed of 2500 rpm for approximately 90 seconds.
4. Select the following menu items: Powertrain / Engine and ECT / Active Test / Control the Injection Volume for A/F Sensor.
5. Perform the Control the Injection Volume for A/F Sensor operation with the engine in an idling condition (press the RIGHT or LEFT button to change the fuel injection volume).
6. Monitor the voltage outputs of the air fuel ratio and heated oxygen sensors (AFS B1S1 and O2S B1S2 or AFS B2S1 and O2S B2S2) displayed on the tester.
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.
Standard voltage:
NOTE: The air fuel ratio sensor has an output delay of a few seconds and the heated oxygen sensor has a maximum output delay of approximately 20 seconds.
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 ignition switch on (IG).
(c) Turn the tester on.
(d) Select the following menu items: Powertrain / Engine and ECT / Trouble Codes.
(e) Read the DTCs.
Result:
HINT: If any DTCs other than P2A00 or P2A03 are output, troubleshoot those DTCs first.
B -- GO TO DTC CHART
A -- Continue to next step.
2. INSPECT AIR FUEL RATIO SENSOR (HEATER RESISTANCE)
(a) Disconnect the air fuel ratio sensor connector.
(b) Measure the resistance according to the value(s) in the table below.
Standard resistance:
Bank 1
Bank 2
(c) Reconnect the air fuel ratio sensor connector.
NG -- REPLACE AIR FUEL RATIO SENSOR
OK -- Continue to next step.
3. CHECK HARNESS AND CONNECTOR (AIR FUEL RATIO SENSOR - ECM)
(a) Disconnect the air fuel ratio sensor connector.
(b) Disconnect the ECM connector.
(c) Measure the resistance according to the value(s) in the table below.
Standard resistance (Check for open):
Bank 1
Bank 2
Standard resistance (Check for short):
Bank 1
Bank 2
(d) Reconnect the ECM connector.
(e) Reconnect the air fuel ratio sensor connector.
NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR (AIR FUEL RATIO SENSOR - ECM)
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) Select the following menu items: Powertrain / Engine and ECT / Trouble Codes / Pending.
Result:
B -- CHECK FOR INTERMITTENT PROBLEMS
A -- Continue to next step.
6. REPLACE AIR FUEL RATIO SENSOR
(a) Replace the air fuel ratio sensor Components.
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) Read the DTCs using the Techstream.
(b) Select the following menu items: Powertrain / Engine and ECT / Trouble Codes / Pending.
Result:
B -- REPLACE ECM
A -- END