Toyota Tundra. Manual — part 1256

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DTC P2A00 A/F SENSOR CIRCUIT SLOW RESPONSE (BANK 1 SENSOR 1); DTC P2A03 A/F
SENSOR CIRCUIT SLOW RESPONSE (BANK 2 SENSOR 1)

DESCRIPTION

Refer to DTC 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.

DTC TROUBLE DETECTION CONDITION CHART

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.

DTC

No.

DTC Detection Condition

Trouble Area

P2A00
P2A03

Calculated value for air-fuel ratio (A/F) sensor response
rate deterioration level is less than threshold



Open or short in A/F sensor
(bank 1, 2 sensor 1) circuit



A/F sensor



A/F sensor heater



ECM

2008 Toyota Tundra

2008 ENGINE PERFORMANCE Engine Control System (1GR-FE) - Tundra

Fig. 223: Identifying Air-Fuel Ratio Sensor Waveform

CONFIRMATION DRIVING PATTERN

HINT:

Performing this confirmation pattern will activate the A/F sensor response monitor.

Fig. 224: Vehicle Speed Driving Pattern

a. Connect the Techstream to the DLC3.

b. Turn the ignition switch ON.

c. Turn the Techstream ON.

d. Clear DTCs (See DTC CHECK/CLEAR ).

2008 Toyota Tundra

2008 ENGINE PERFORMANCE Engine Control System (1GR-FE) - Tundra

e. Enter the following menus: Powertrain/Engine and ECT/Monitor/O2 Sensor/Details.

f. Check that RES RATE B1S1 and RES RATE B2S1 are Incomplete.

g. Start the engine and warm it up.

h. 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.

i. Check the monitor result values on Techstream by entering the following menus: Powertrain/Engine and

ECT/Monitor/O2 Sensor/Details/RES RATE B1S1 or RES RATE B2S1/Details.

j. If the values indicated on the Techstream do not change, perform READINESS MONITOR DRIVE

PATTERN for the A/F sensor and the heated oxygen sensor (See READINESS MONITOR DRIVE
PATTERN ).

HINT:

Completion of all A/F sensor monitors is required to change the value in RES RATE B1S1 and RES
RATE B2S1.

k. Note the value of the RES RATE B1S1 and RES RATE B2S1.

l. Enter the following menus: Powertrain/Engine and ECT/Trouble Codes/Pending.

m. Check if any DTCs (any pending DTCs) are set.

MONITOR STRATEGY

MONITOR STRATEGY

TYPICAL ENABLING CONDITIONS

TYPICAL ENABLING CONDITIONS

Related DTCs

P2A00: A/F sensor (bank 1) slow response
P2A03: A/F sensor (bank 2) slow response

Required Sensors/Components (Main)

A/F sensor

Required Sensors/Components (Related)

Vehicle speed sensor, Crankshaft position sensor

Frequency of Operation

Once per driving cycle

Duration

10 to 15 seconds

MIL Operation

2 driving cycles

Sequence of Operation

None

Monitor runs whenever following DTCs not present

P0031, P0032, P0051, P0052 (A/F sensor heater -
Sensor 1)
P0102, P0103 (MAF meter)
P0110, P0112, P0113 (IAT sensor)
P0115 - P0118 (ECT sensor)
P0120 - P0223, P2135 (TP sensor)
P0125 (Insufficient ECT for Closed Loop)
P0171, P0172 (Fuel system)
P0300 - P0306 (Misfire)

2008 Toyota Tundra

2008 ENGINE PERFORMANCE Engine Control System (1GR-FE) - Tundra

TYPICAL MALFUNCTION THRESHOLDS

TYPICAL MALFUNCTION THRESHOLDS

MONITOR RESULT

Refer to CHECKING MONITOR STATUS .

WIRING DIAGRAM

Refer to DTC P2195 .

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.

1. Connect the Techstream to the DLC3.

P0335 (CKP sensor)
P0340 (VVT sensor)
P0455, P0456 (EVAP system)
P0500 (VSS)
P2196, P2198 (A/F sensor - rationality)

Active A/F control

Performing

Active A/F control performed when following
conditions met

-

Battery voltage

11 V or more

Engine coolant temperature

75°C (167°F) or more

Idling

OFF

Engine RPM

Less than 4000 RPM

A/F sensor status

Activated

Fuel-cut

OFF

Engine load

10 to 80%

Shift position

2 or more

Catalyst monitor

Not yet

Intake air amount

3 to 20 g/sec.

Response rate deterioration level

Less than 0.2 V

2008 Toyota Tundra

2008 ENGINE PERFORMANCE Engine Control System (1GR-FE) - Tundra