SFI SYSTEM, Diagnostic DTC:P2A00, P2A03

DTC Code	DTC Name
P2A00	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 Click here.

Tech Tips

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 (TWC) and located near the engine assembly.

DTC No.	DTC Detection Condition	Trouble Area
P2A00 P2A03	The calculated value for the air fuel ratio sensor response rate deterioration level is less than the threshold (2 trip detection logic).	Open or short in air fuel ratio sensor (bank 1, 2 sensor 1) circuit Air fuel ratio sensor Air fuel ratio sensor heater ECM

DTC No.

DTC Detection Condition

Trouble Area

P2A00

P2A03

The calculated value for the air fuel ratio sensor response rate deterioration level is less than the threshold (2 trip detection logic).

Open or short in air fuel ratio sensor (bank 1, 2 sensor 1) circuit
Air fuel ratio sensor
Air fuel ratio sensor heater
ECM

CONFIRMATION DRIVING PATTERN

Tech Tips

Performing this confirmation driving pattern will activate the air fuel ratio sensor response monitor.

(a) Connect the GTS to the DLC3.
(b) Turn the ignition switch to ON.
(c) Turn the GTS on.
(d) Clear DTCs Click here.
(e) Start the engine and warm it up. (Procedure "g")
(f) Drive the vehicle at a constant speed between 40 km/h and 120 km/h (25 mph and 75 mph) for 3 minutes or more. (Procedure "h")
(g) Turn the ignition switch off.
(h) Repeat steps Procedure "g" and "h" above again.
(i) Enter the following menus: Powertrain / Engine and ECT / Trouble Codes.
(j) Check if any DTCs (any pending DTCs) are output.

WIRING DIAGRAM

Refer to DTC P2195 Click here.

INSPECTION PROCEDURE

Tech Tips

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 GTS.

Connect the GTS to the DLC3.
Start the engine and turn the GTS on.
Warm up the engine at an engine speed of 2500 rpm for approximately 90 seconds.
On the GTS, enter the following menus: Powertrain / Engine and ECT / Active Test / Control the Injection Volume for A/F Sensor.
Perform the Active Test operation with the engine idling (press the RIGHT or LEFT button to change the fuel injection volume).
Monitor the output voltages of the air fuel ratio and heated oxygen sensors (AFS Voltage B1S1 and O2S B1S2 or AFS Voltage B2S1 and O2S B2S2) displayed on the GTS.

Tech Tips

The Control the Injection Volume for A/F Sensor operation lowers the fuel injection volume by 12.5% or increases the injection volume by 12.5%.
Each sensor reacts in accordance with increases and decreases in the fuel injection volume.

GTS Display (Sensor)	Injection Volume	Status	Voltage
AFS Voltage B1S1 or AFS Voltage B2S1 (Air fuel ratio sensor)	+12.5%	Rich	Below 3.1 V
AFS Voltage B1S1 or AFS Voltage B2S1 (Air fuel ratio sensor)	-12.5%	Lean	Higher than 3.4 V
O2S B1S2 or O2S B2S2 (Heated oxygen sensor)	+12.5%	Rich	Higher than 0.55 V
O2S B1S2 or O2S B2S2 (Heated oxygen sensor)	-12.5%	Lean	Below 0.4 V

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.

Case	Air Fuel Ratio Sensor (Sensor 1) Output Voltage	Heated oxygen Sensor (Sensor 2) Output Voltage	Main Suspected Trouble Area
1			-
2			Air fuel ratio sensor Air fuel ratio sensor heater Air fuel ratio sensor circuit
3			Heated oxygen sensor Heated oxygen sensor heater Heated oxygen sensor circuit
4			Fuel injector assembly Fuel pressure Gas leakage from exhaust system (air fuel ratio extremely rich or lean)

Following the Control the Injection Volume for A/F Sensor procedure enables technicians to check and graph the voltage outputs of both the air fuel ratio and heated oxygen sensors.
To display the graph, enter the following menus: Powertrain / Engine and ECT / Active Test / Control the Injection Volume for A/F Sensor / AFS Voltage B1S1 and O2S B1S2 or AFS Voltage B2S1 and O2S B2S2.

Tech Tips

DTC P2A00 or P2A03 may be also stored when the air fuel ratio is stuck at a rich or lean value.
A low air fuel ratio sensor voltage could be caused by a rich air-fuel mixture. Check for conditions that would cause the engine to run rich.
A high air fuel ratio 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 GTS. 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

CHECK FOR ANY OTHER DTCS OUTPUT (IN ADDITION TO DTC P2A00 AND/OR P2A03)

Connect the GTS to the DLC3.
Turn the ignition switch to ON.
Turn the GTS on.
Enter the following menus: Powertrain / Engine and ECT / Trouble Codes.

Read DTCs.

Result
Result	Proceed to
P2A00 and/or P2A03	A
P2A00 and/or P2A03 and other DTCs	B

Tech Tips

If any DTCs other than P2A00 or P2A03 are output, troubleshoot those DTCs first.

GO TO DTC CHART Click here

INSPECT AIR FUEL RATIO SENSOR (HEATER RESISTANCE)
1. Inspect the air fuel ratio sensor Click here.
NG
REPLACE AIR FUEL RATIO SENSOR Click here

OK

CHECK HARNESS AND CONNECTOR (AIR FUEL RATIO SENSOR - ECM)

Disconnect the air fuel ratio sensor connector.
Disconnect the ECM connector.

Measure the resistance according to the value(s) in the table below.

Standard Resistance

for LHD
Tester Connection	Condition	Specified Condition
C22-1 (HA1A) - C45-22 (HA1A)	Always	Below 1 Ω
C23-1 (HA2A) - C45-20 (HA2A)	Always	Below 1 Ω
C22-1 (HA1A) or C45-22 (HA1A) - Body ground	Always	10 kΩ or higher
C23-1 (HA2A) or C45-20 (HA2A) - Body ground	Always	10 kΩ or higher

for RHD
Tester Connection	Condition	Specified Condition
C22-1 (HA1A) - C46-22 (HA1A)	Always	Below 1 Ω
C23-1 (HA2A) - C46-20 (HA2A)	Always	Below 1 Ω
C22-1 (HA1A) or C46-22 (HA1A) - Body ground	Always	10 kΩ or higher
C23-1 (HA2A) or C46-20 (HA2A) - Body ground	Always	10 kΩ or higher

Reconnect the air fuel ratio sensor connector.
Reconnect the ECM connector.

REPAIR OR REPLACE HARNESS OR CONNECTOR

PERFORM CONFIRMATION DRIVING PATTERN

NEXT

CHECK WHETHER DTC OUTPUT RECURS (DTC P2A00 AND/OR P2A03)

Connect the GTS to the DLC3.
Turn the ignition switch to ON and turn the GTS on.
Enter the following menus: Powertrain / Engine and ECT / Trouble Codes / Pending.

Read DTCs.

Result
Result	Proceed to
P2A00 and/or P2A03	A
No output	B

CHECK FOR INTERMITTENT PROBLEMS Click here

REPLACE AIR FUEL RATIO SENSOR
1. Replace the air fuel ratio sensor Click here.
NEXT
PERFORM CONFIRMATION DRIVING PATTERN

NEXT

CHECK WHETHER DTC OUTPUT RECURS (DTC P2A00 AND/OR P2A03)

Connect the GTS to the DLC3.
Turn the ignition switch to ON and turn the GTS on.
Enter the following menus: Powertrain / Engine and ECT / Trouble Codes / Pending.

Read DTCs.

Result
Result)	Proceed to
No output	A
P2A00 and/or P2A03	B

CHECK EXTREMELY RICH OR LEAN ACTUAL AIR FUEL RATIO (REFER TO DTC P0171) Click here

END