Toyota Tundra. Manual — part 1244

P2238 and P2241 (A/F sensor low impedance)

TYPICAL ENABLING CONDITIONS

Other:

TYPICAL ENABLING CONDITIONS

TYPICAL MALFUNCTION THRESHOLDS

P2237 and P2240 (A/F sensor open circuit between A1A+ and A1A-/A2A+ and A2A-)

TYPICAL MALFUNCTION THRESHOLDS

P2238 and P2241 (A/F sensor low impedance)

TYPICAL MALFUNCTION THRESHOLDS

P2238 and P2241 (A/F sensor short circuit between A1A+ and GND/A2A+ and GNP)

TYPICAL MALFUNCTION THRESHOLDS

P2239 and P2242 (A/F sensor short circuit between A1A+ and +B/A2A+ and +B)

TYPICAL MALFUNCTION THRESHOLDS

P2252 and P2255 (A/F sensor short circuit between A1A- and GND/A2A- and GND)

TYPICAL MALFUNCTION THRESHOLDS

P2253 and P2256 (A/F sensor short circuit between A1A- and +B/A2A- and +B)

Battery voltage

11 V or more

Estimated sensor temperature

700 to 800°C (1292 to 1472°F)

Engine coolant temperature

5°C (41°F) or higher

Fuel cut

No executed

Battery voltage

11 V or more

Ignition switch

ON

Time after ignition switch is OFF to ON

5 seconds or more

A/F sensor admittance

Below 0.002 1/ohms

A/F sensor admittance

Below 0.022 1/ohms

A1A+/A2A+ terminal voltage

0.5 V or less

A1A+/A2A-terminal voltage

More than 4.5 V

A1A-/A2A- terminal voltage

0.5 V or less

2008 Toyota Tundra

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

TYPICAL MALFUNCTION THRESHOLDS

P2238 and P2241 (A/F sensor short circuit between A1A+ and A1A-/A2A+ and A2A-)

TYPICAL MALFUNCTION THRESHOLDS

COMPONENT OPERATING RANGE

COMPONENT OPERATING RANGE

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.

2. Start the engine and turn the Techstream ON.

3. Warm up the engine at an engine speed of 2500 RPM for approximately 90 seconds.

4. On the Techstream, enter the following menus: Powertrain/Engine and ECT/Active Test/Control the

Injection Volume for A/F sensor.

5. Perform the Active Test 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 B1 S1 and O2S B1 S2 or AFS B2 S1 and

O2S B2 S2) displayed on the Techstream.

A1A-/A2A- terminal voltage

More than 4.5 V

Difference between A1A+ terminal and A1A- terminal voltage/A2A+ terminal and A2A-
terminal voltage

0.1 V or
less

A/F sensor admittance

0.022 1/ohms or
more

A1A+/A2A+ terminal voltage

0.6 to 4.5 V

A1A-/A2A- terminal voltage

0.6 to 4.5 V

Difference between A1A+ and A1A- terminal voltages/A2A+ and A2A-terminal
voltages

0.1 to 0.8 V

2008 Toyota Tundra

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

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.

VOLTAGE REFERENCE

VOLTAGE REFERENCE



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 B1 S1 and O2S B1 S2 or AFS B2
S1 and O2S B2 S2.

Tester Display (Sensor)

Injection Volume Status

Voltage

AFS B1 S1 or AFS B2 S1 (A/F)

+25%

Rich

Less than 3.0 V

AFS B1 S1 or AFS B2 S1 (A/F)

-12.5%

Lean More than 3.35 V

O2S B1 S2 or O2S B2 S2 (HO2)

+25%

Rich More than 0.55 V

O2S B1 S2 or O2S B2 S2 (HO2)

-12.5%

Lean

Less than 0.4 V

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.

Case

A/F Sensor (Sensor 1) Output

Voltage

HO2 Sensor (Sensor 2)

Output Voltage

Main Suspected Trouble Area

1

-

2



A/F sensor



A/F sensor heater



A/F sensor circuit

3



HO2 sensor



HO2 sensor heater



HO2 sensor circuit

4



Injector



Fuel pressure



Gas leakage from exhaust
system (Air-fuel ratio
extremely rich or lean)

2008 Toyota Tundra

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

HINT:

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.

1. CHECK HARNESS AND CONNECTOR (A/F SENSOR - ECM) (See INSPECTION

PROCEDURE )

NG : REPAIR OR REPLACE HARNESS OR CONNECTOR

OK : Go to next step.

2. REPLACE AIR FUEL RATIO SENSOR

a. Replace the air-fuel ratio sensor (See REMOVAL ).

3. CHECK WHETHER DTC OUTPUT RECURS

a. Connect the Techstream to the DLC3.

b. Turn the ignition switch ON and turn the Techstream ON.

c. Clear the DTCs (See DTC CHECK/CLEAR ).

d. Start the engine.

e. Allow the engine to idle for 5 minutes or more.

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

g. Read pending DTCs.

Result

RESULT CHART

B : REPLACE ECM (See REMOVAL )

A : END

DTC P2420 EVAPORATIVE EMISSION SYSTEM SWITCHING VALVE CONTROL CIRCUIT
HIGH

DTC SUMMARY

DTC SUMMARY CHART

Display (DTC Output)

Proceed To

No output

A

P2237, P2240, P2238, P2241, P2239, P2242, P2252, P2255, P2253 or P2256

B

DTC

Monitoring

Item

Malfunction Detection

Condition

Trouble Area

Detection

Timing

Detection

Logic

2008 Toyota Tundra

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