Toyota Tundra. Manual — part 1168

HINT:

When any of these DTCs are set, check the ECT by entering the following menus: Powertrain/Engine and
ECT/Data List/All Data/Coolant Temp.

TEMPERATURE CHART

MONITOR DESCRIPTION

The Engine Coolant Temperature (ECT) sensor is used to monitor the ECT. The ECT sensor has a thermistor
with a resistance that varies according to the temperature of the engine coolant. When the coolant temperature is
low, the resistance in the thermistor increases. When the temperature is high, the resistance drops. These
variations in resistance are reflected in the output voltage from the sensor. The ECM monitors the sensor
voltage and uses this value to calculate the ECT. When the sensor output voltage deviates from the normal
operating range, the ECM interprets this as a fault in the ECT sensor and sets 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 ECT sensor circuit, and sets DTC P0118. Conversely, if the voltage output is less than 0.14 V for
0.5 seconds or more, the ECM determines that there is a short in the sensor circuit, and sets DTC P0117.

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

MONITOR STRATEGY

MONITOR STRATEGY

TYPICAL ENABLING CONDITIONS

P0118

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



Open in ECT sensor circuit



ECT sensor



ECM

Temperature Displayed

Malfunction

-40°C (-40°F)

Open circuit

140°C (284°F) or higher

Short circuit

Related DTCs

P0115: ECT sensor range check (Fluctuating)
P0117: ECT sensor range check (Low voltage)
P0118: ECT sensor range check (High voltage)

Required Sensors/Components (Main)

ECT sensor

Required Sensors/Components (Related)

-

Frequency of Operation

Continuous

Duration

0.5 seconds

MIL Operation

Immediate

Sequence of Operation

None

2008 Toyota Tundra

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

TYPICAL ENABLING CONDITIONS

TYPICAL MALFUNCTION THRESHOLDS

P0115:

TYPICAL MALFUNCTION THRESHOLDS

P0117:

TYPICAL MALFUNCTION THRESHOLDS

P0118:

TYPICAL MALFUNCTION THRESHOLDS

COMPONENT OPERATING RANGE

COMPONENT OPERATING RANGE

WIRING DIAGRAM

Fig. 68: Engine Coolant Temperature Circuit Diagram

INSPECTION PROCEDURE

Monitor runs whenever following DTCs not present

None

ECT sensor voltage

Less than 0.14 V, or more than 4.91 V

ECT sensor voltage [ECT]

Less than 0.14 V [More than 140°C (284°F)]

ECT sensor voltage [ECT]

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

ECT sensor voltage [ECT]

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

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. READ OUTPUT DTC

a. Connect the Techstream to the DLC3.

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

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

d. Read the DTCs.

Result

RESULT CHART

B : Go to step 5

C : Go to step 3

A : Go to next step

2. READ VALUE USING TECHSTREAM (ENGINE COOLANT TEMPERATURE)

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/Data List/All Data/Coolant Temp.

e. Read the value displayed on the Techstream.

Standard value:

Between 80°C and 100°C (167°F and 212 F) with warm engine.

Result

RESULT CHART

Display (DTC Output) Proceed To

P0115

A

P0117

B

P0118

C

Temperature Displayed

Proceed To

-40°C (-40°F)

A

140°C (284°F) or higher

B

2008 Toyota Tundra

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

HINT:



If there is an open circuit, the Techstream indicates 40°C (-40°F).



If there is a short circuit, the Techstream indicates 140°C (284°F) or higher.

B : Go to step 5

C : CHECK FOR INTERMITTENT PROBLEMS (See CHECK FOR INTERMITTENT
PROBLEMS )

A : Go to next step

3. READ VALUE USING TECHSTREAM (CHECK FOR OPEN IN WIRE HARNESS)

a. Disconnect the D28 Engine Coolant Temperature (ECT) sensor connector.

b. Connect terminals 1 and 2 of the ECT sensor connector on the wire harness side.

c. Connect the Techstream to the DLC3.

d. Turn the ignition switch ON.

e. Turn the Techstream ON.

f. Enter the following menus: Powertrain/Engine and ECT/Data List/All Data/Coolant Temp.

g. Read the value displayed on the Techstream.

Standard value:

140°C (284°F) or higher.

NG : Go to step 4

Between 80°C and 100°C (176°F and 212°F)

C

2008 Toyota Tundra

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