Toyota Tundra. Manual — part 1526

After engine stop:

TYPICAL ENABLING CONDITIONS - AFTER ENGINE STOP

After cold engine start:

TYPICAL ENABLING CONDITIONS - AFTER COLD ENGINE STOP

TYPICAL MALFUNCTION THRESHOLDS

After engine stop:

TYPICAL MALFUNCTION THRESHOLDS - AFTER ENGINE STOP

After cold engine start:

TYPICAL MALFUNCTION THRESHOLDS - AFTER COLD ENGINE STOP

WIRING DIAGRAM

Refer to DTC P0110 (see WIRING DIAGRAM).

INSPECTION PROCEDURE

1. CHECK ANY OTHER DTCS OUTPUT (IN ADDITION TO DTC P0111)

a. Connect the Techstream to the DLC3.

b. Turn the ignition switch to ON.

present

Sensor)

Time after engine start

10 seconds or more

Battery voltage

10.5 V or more

ECT change since engine stop

-40°C (-40°F) or more

ECT before engine stop

70°C (158°F) or more

Accumulated MAF amount before engine stop

3240 g or more

Key-off duration

30 minutes

Key-off duration

5 hours

Time after engine start

10 seconds or more

ECT

70°C (158°F) or more

Accumulated MAF amount

3240 g or more

Either of the following conditions 1 or 2 is met:

-

1. Duration while engine load is low

120 seconds or more

2. Duration while engine load is high

10 seconds or more

IAT change

Less than 1°C (2°F)

IAT change

Less than 1°C (2°F)

2009 Toyota Tundra

2009 ENGINE PERFORMANCE Engine Control System (3UR-FBE) - Tundra

c. Turn the Techstream ON.

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

e. Read DTCs.

Result

RESULT REFERENCE

HINT:

If any DTCs other than P0111 are output, troubleshoot those DTCs first.

B: REPLACE MASS AIR FLOW METER (See REMOVAL )

A: GO TO DTC CHART

DTC P0112 INTAKE AIR TEMPERATURE CIRCUIT LOW INPUT; DTC P0113 INTAKE AIR
TEMPERATURE CIRCUIT HIGH INPUT

DESCRIPTION

Fig. 73: Resistance And Temperature Graph
Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.

The Intake Air Temperature (IAT) sensor, mounted on the Mass Air Flow (MAF) meter, monitors the IAT. The
IAT sensor has a built-in thermistor with a resistance that varies according to the temperature of the intake air.
When the IAT is low, the resistance of the thermistor increases. When the temperature is high, the resistance
drops. These variations in resistance are transmitted to the ECM as voltage changes (see Fig. 73).

Display (DTC Output)

Proceed to

P0111 and other DTCs are output

A

P0111 is output

B

2009 Toyota Tundra

2009 ENGINE PERFORMANCE Engine Control System (3UR-FBE) - Tundra

The IAT sensor is powered by a 5 V supply from the THA terminal of the ECM, via resistor R.

Resistor R and the IAT sensor are connected in series. When the resistance value of the IAT sensor changes,
according to changes in the IAT, the voltage at terminal THA also varies. Based on this signal, the ECM
increases the fuel injection volume when the engine is cold to improve driveability.

HINT:

When any of DTCs P0112 and P0113 are set, the ECM enters fail-safe mode. During fail-safe mode, the IAT is
estimated to be 20°C (68°F) by the ECM. Fail-safe mode continues until a pass condition is detected.

DTC DETECTION CONDITION AND TROUBLE AREA REFERENCE CHART

HINT:

When any of these DTCs are set, check the IAT by entering the following menus: Powertrain/Engine and
ECT/All Data/Intake Air.

DATA LIST REFERENCE

MONITOR DESCRIPTION

The ECM monitors the sensor voltage and uses this value to calculate the IAT. When the sensor output voltage
deviates from the normal operating range, the ECM interprets this as a malfunction in the IAT sensor and stores
a DTC.

Example:

If the sensor output voltage is more than 4.91 V for 0.5 seconds or more, the ECM determines that there is an
open in the IAT sensor circuit, and sets DTC P0113. Conversely, if the output voltage is less than 0.18 V for 0.5
seconds or more, the ECM determines that there is a short in the sensor circuit, and sets DTC P0112.

If the malfunction is not repaired successfully, a DTC is stored 0.5 seconds after the engine is next started.

DTC

DTC Detection Condition

Trouble Area

P0112

Short in IAT sensor circuit for 0.5
seconds (1 trip detection logic)



Short in IAT sensor circuit



IAT sensor (built into MAF
meter)



ECM

P0113

Open in IAT sensor circuit for 0.5
seconds (1 trip detection logic)



Open in IAT sensor circuit



IAT sensor (built into MAF
meter)



ECM

Temperature Displayed

Malfunction

-40°C (-40°F)

Open circuit

140°C (284°F) or higher

Short circuit

2009 Toyota Tundra

2009 ENGINE PERFORMANCE Engine Control System (3UR-FBE) - Tundra

MONITOR STRATEGY

MONITOR STRATEGY

TYPICAL ENABLING CONDITIONS

TYPICAL ENABLING CONDITIONS

TYPICAL MALFUNCTION THRESHOLDS

P0112:

TYPICAL MALFUNCTION THRESHOLDS - P0112

P0113:

TYPICAL MALFUNCTION THRESHOLDS - P0113

COMPONENT OPERATING RANGE

COMPONENT OPERATING RANGE

WIRING DIAGRAM

Related DTCs

P0110: IAT sensor range check (Fluctuating)
P0112: IAT sensor range check (Low voltage)
P0113: IAT sensor range check (High voltage)

Required Sensors/Components (Main)

IAT sensor

Required Sensors/Components (Related)

-

Frequency of Operation

Continuous

Duration

0.5 seconds

MIL Operation

Immediate

Sequence of Operation

None

Monitor runs whenever following DTCs not present

None

IAT sensor voltage [IAT]

Less than 0.18 V [More than 140°C (284°F)]

IAT sensor voltage [IAT]

More than 4.91 V [Less than -40°C (-40°F)]

IAT sensor voltage [IAT]

0.18 to 4.91 V [-40 to 140°C (-40 to 284°F)]

2009 Toyota Tundra

2009 ENGINE PERFORMANCE Engine Control System (3UR-FBE) - Tundra