Toyota Tundra. Manual — part 1170

MIL is illuminated and a DTC is set.

ECT sensor soak monitor

If the ECT sensor value does not change after the warmed up engine is stopped and then the next cold engine
start is performed, it is determined that a malfunction has occurred. If this is detected in 2 consecutive driving
cycles, the MIL is illuminated and a DTC is set.

MONITOR STRATEGY

MONITOR STRATEGY

TYPICAL ENABLING CONDITIONS

ECT sensor cold start monitor:

TYPICAL ENABLING CONDITIONS

ECT sensor soak monitor:

TYPICAL ENABLING CONDITIONS

Related DTCs

P0116: Engine coolant temperature (ECT) sensor cold start
monitor
P0116: ECT sensor soak monitor

Required Sensors/Components (Main) ECT sensor
Required Sensors/Components
(Related)

None

Frequency of Operation

Once per driving cycle

Duration

5 hours or more

MIL Operation

2 driving cycles

Sequence of Operation

None

Monitor runs whenever following DTCs not
present

P0102 to P0103: Mass Air Flow (MAF) meter
P0110 to P0113: Intake Air Temperature (IAT)
sensor

Battery voltage

10.5 V or more

Time after engine start

1 second or more

ECT at engine start

Less than 60°C (140°F)

IAT sensor circuit

OK

Soak time

0 or more

Accumulated MAF

1670 g or more

Engine

Running

Fuel cut

OFF

Difference between ECT at engine start and IAT

Less than 40°C (72°F)

Monitor runs whenever following DTCs not present

P0102 to P0103: MAF meter

2008 Toyota Tundra

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

TYPICAL MALFUNCTION THRESHOLDS

ECT sensor cold start monitor:

TYPICAL MALFUNCTION THRESHOLDS

ECT sensor soak monitor:

TYPICAL MALFUNCTION THRESHOLDS

COMPONENT OPERATING RANGE

COMPONENT OPERATING RANGE

INSPECTION PROCEDURE

HINT:



If any of DTCs P0115, P0117, P0118 or P0125 are set simultaneously with DTC P0116, the ECT sensor
may have an open or a short circuit. Troubleshoot those DTCs first.



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 ANY OTHER DTCS OUTPUT (IN ADDITION TO DTC P0116)

a. Connect the Techstream to the DLC3.

b. Turn the ignition switch ON.

c. Turn the Techstream ON.

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

e. Read the DTC.

Result

Battery voltage

10.5 V or more

Engine

Running

Soak time

5 hours or more

Either (a) or (b) condition met

-

(a) ECT

60°C (140°F) or more

(b) Accumulated MAF

3295 g or more

ECT sensor value change

Less than 5°C (9°F)

Difference between current ECT sensor value and previous ECT sensor value when
engine stopped

Less than 5°C (9°
F)

ECT

ECT sensor value changes in accordance with actual ECT

2008 Toyota Tundra

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

RESULT CHART

B : GO TO DTC CHART (See DIAGNOSTIC TROUBLE CODE CHART )

A : Go to next step

2. INSPECT WATER INLET WITH THERMOSTAT

a. Remove the water inlet with thermostat. (See REMOVAL ).

b. Measure the valve opening temperature of the thermostat.

Standard value:

80 to 84°C (176 to 183°F)

HINT:

In addition to the above check, confirm that the valve is completely closed when the temperature is
below the standard.

c. Reinstall the water inlet with thermostat. (See INSTALLATION ).

NG : REPLACE WATER INLET WITH THERMOSTAT . (See THERMOSTAT ).

OK : REPLACE ENGINE COOLANT TEMPERATURE SENSOR . (See REMOVAL).

DTC P011B ENGINE COOLANT TEMPERATURE/INTAKE AIR TEMPERATURE CORRELATION

DESCRIPTION

The engine has two temperature sensors, an Engine Coolant Temperature (ECT) sensor and an Intake Air
Temperature (IAT) sensor, to detect the temperature while the engine is in operation. A thermistor, whose
resistance value varies according to the temperature, is built into each sensor. When the temperature 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. Based on these temperature signals output from the
sensors, the ECM determines the fuel injection time and the ignition timing to control the engine.

DTC TROUBLE DETECTION CONDITION CHART

Display (DTC Output) Proceed To

P0116

A

P0116 and other DTCs

B

DTC

No.

DTC Detection Condition

Trouble Area

All of following conditions met: (2 trip detection logic)

a. Battery voltage 10.5 V or more

b. 7 hours or more elapsed from engine stops on previous

2008 Toyota Tundra

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

Fig. 73: Engine Coolant Temperature / Intake Air Temperature Graph

HINT:



Waiting is required to prevent the temperature of the engine from affecting the readings. If the engine has
been operated recently, it will not be possible to accurately compare the readings.



For diagnosis, in order to duplicate the detection conditions of the DTC, it is necessary to park the vehicle
for 7 hours. Parking the vehicle for 7 hours ensures that the actual temperature of the ECT and IAT are
very similar. When the vehicle has been parked for less than 7 hours, differences in the readings may
exist, and this does not necessarily indicate a fault.

MONITOR DESCRIPTION

The ECM monitors the difference between the Engine Coolant Temperature (ECT) and the Intake Air
Temperature (IAT) when the engine is started cold to detect the engine temperature conditions accurately. The
monitor runs when the engine is started cold after 7 hours or more have elapsed since the engine was stopped

P011B

trip

c. 736 seconds after cold engine starts

d. Minimum Intake Air Temperature (IAT) after engine

starts more than -10°C (14°F)

e. Average Engine Coolant Temperature (ECT) before

engine starts more than -10°C (14°F)

f. Difference between readings of ECT and IAT greater

than 20°C (36°F)



Intake air temperature
(IAT) sensor



Engine coolant temperature
(ECT) sensor



ECM

2008 Toyota Tundra

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