Toyota Tundra Service Manual: Engine Coolant Temperature Circuit Malfunction (P0115,P0117,P0118)

Toyota Tundra Service Manual / Engine, Hybrid System / 1ur-fe Engine Control / Sfi System / Engine Coolant Temperature Circuit Malfunction (P0115,P0117,P0118)

DESCRIPTION

A thermistor, whose resistance value varies according to the ECT, is built into the Engine Coolant Temperature (ECT) sensor.

The structure of the sensor and its connection to the ECM are the same as those of the Intake Air Temperature (IAT) sensor.

HINT:

When DTC P0115, P0117 or P0118 is stored, the ECM enters fail-safe mode. During fail-safe mode, the ECT is estimated to be 80°C (176°F) by the ECM. Fail-safe mode continues until a pass condition is detected.

DTC No.

DTC Detection Condition

Trouble Area

P0115

Open or short in ECT sensor circuit for 0.5 seconds

(1 trip detection logic)

  • Open or short in ECT sensor circuit
  • ECT sensor
  • ECM

P0117

Short in ECT sensor circuit for 0.5 seconds

(1 trip detection logic)

  • Short in ECT sensor circuit
  • ECT sensor
  • ECM

P0118

Open in ECT sensor circuit for 0.5 seconds

(1 trip detection logic)

  • Open in ECT sensor circuit
  • ECT sensor
  • ECM

HINT:

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

Temperature Displayed

Malfunction

-40°C (-40°F)

Open circuit

140°C (284°F) or higher

Short circuit

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 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 ECT sensor circuit, and stores 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 stores DTC P0117.

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

MONITOR STRATEGY

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

TYPICAL ENABLING CONDITIONS

Monitor runs whenever following DTCs not present

None

TYPICAL MALFUNCTION THRESHOLDS

P0115

ECT sensor voltage

Less than 0.14 V, or more than 4.91 V [More than 135°C (275°F), or less than -60°C (-76°F)]

P0117

ECT sensor voltage [ECT]

Less than 0.14 V [More than 135°C (275°F)]

P0118

ECT sensor voltage [ECT]

More than 4.91 V [Less than -60°C (-76°F)]

COMPONENT OPERATING RANGE

ECT sensor voltage [ECT]

0.14 to 4.91 V [-60 to 135°C (-76 to 275°F)]

CONFIRMATION DRIVING PATTERN

  1. Connect the Techstream to the DLC3.
  2. Turn the ignition switch to ON and turn the Techstream on.
  3. Clear DTCs (even if no DTCs are stored, perform the clear DTC operation).
  4. Turn the ignition switch off and wait for at least 30 seconds.
  5. Turn the ignition switch to ON and turn the Techstream on.
  6. Wait 0.5 seconds or more.
  7. Enter the following menus: Powertrain / Engine and ECT / Trouble Codes.
  8. Read the pending DTCs.

    HINT:

    • If a pending DTC is output, the system is malfunctioning.
    • If a pending DTC is not output, perform the following procedure.
  9. Enter the following menus: Powertrain / Engine and ECT / Utility / All Readiness.
  10. Input the DTC: P0115, P0117 or P0118.
  11. Check the DTC judgment result.

    Tester Display

    Description

    NORMAL

    • DTC judgment completed
    • System normal

    ABNORMAL

    • DTC judgment completed
    • System abnormal

    INCOMPLETE

    • DTC judgment not completed
    • Perform driving pattern after confirming DTC enabling conditions

    N/A

    • Unable to perform DTC judgment
    • Number of DTCs which do not fulfill DTC preconditions has reached ECU memory limit
  12. If the test result is INCOMPLETE or N/A and no pending DTC is output, perform a universal trip and check for permanent DTCs (See page ).

    HINT:

    • If a permanent DTC is output, the system is malfunctioning.
    • If no permanent DTC is output, the system is normal.

WIRING DIAGRAM

CAUTION / NOTICE / HINT

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.

PROCEDURE

1.

READ VALUE USING TECHSTREAM (ENGINE COOLANT TEMPERATURE)

(a) Connect the Techstream to the DLC3.

(b) Turn the ignition switch to ON.

(c) Turn the Techstream on.

(d) Enter the following menus: Powertrain / Engine and ECT / Data List / Coolant Temp.

(e) Read the value displayed on the Techstream.

Standard value:

Between 75 and 100°C (167 and 212°F) with warm engine.

Result

Result

Proceed to

-40°C (-40°F)

A

140°C (284°F) or higher

B

Between 75 and 100°C (167 and 212°F)

C

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 4

C

CHECK FOR INTERMITTENT PROBLEMS

A

2.

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

(a) Disconnect the 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 to ON.

(e) Turn the Techstream on.

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

(g) Read the value displayed on the Techstream.

Standard value:

140°C (284°F) or higher

HINT:

Perform "Inspection After Repair" after replacing the engine coolant temperature sensor (See page ).

OK

CONFIRM GOOD CONNECTION TO SENSOR. IF OK, REPLACE ENGINE COOLANT TEMPERATURE SENSOR

NG

3.

CHECK HARNESS AND CONNECTOR (ENGINE COOLANT TEMPERATURE SENSOR - ECM)

(a) Disconnect the ECT sensor connector.

(b) Disconnect the ECM connector.

(c) Measure the resistance according to the value(s) in the table below.

Standard Resistance:

Tester Connection

Condition

Specified Condition

D28-2 - D74-76 (THW)

Always

Below 1 Ω

D28-1 - D74-98 (E2)

Always

Below 1 Ω

OK

CONFIRM GOOD CONNECTION TO ECM. IF OK, REPLACE ECM

NG

REPAIR OR REPLACE HARNESS OR CONNECTOR

4.

READ VALUE USING TECHSTREAM (CHECK FOR SHORT IN WIRE HARNESS)

(a) Disconnect the ECT sensor connector.

(b) Connect the Techstream to the DLC3.

(c) Turn the ignition switch to ON.

(d) Turn the Techstream on.

(e) Enter the following menus: Powertrain / Engine and ECT / Data List / Coolant Temp.

(f) Read the value displayed on the Techstream.

Standard value:

-40°C (-40°F)

HINT:

Perform "Inspection After Repair" after replacing the engine coolant temperature sensor (See page ).

OK

REPLACE ENGINE COOLANT TEMPERATURE SENSOR

NG

5.

CHECK HARNESS AND CONNECTOR (ENGINE COOLANT TEMPERATURE SENSOR - ECM)

(a) Disconnect the ECT sensor connector.

(b) Disconnect the ECM connector.

(c) Measure the resistance according to the value(s) in the table below.

Standard Resistance:

Tester Connection

Condition

Specified Condition

D28-2 or D74-76 (THW) - Body ground

Always

10 kΩ or higher

OK

REPLACE ECM

NG

REPAIR OR REPLACE HARNESS OR CONNECTOR

    Intake Air Temperature Circuit Low Input (P0112,P0113)

    Engine Coolant Temperature Circuit Range / Performance Problem (P0116)

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