GSIC - Global Service Information Center

### DTC P0115 Engine Coolant Temperature Circuit

### DTC P0117 Engine Coolant Temperature Circuit Low Input

### DTC P0118 Engine Coolant Temperature Circuit High Input

## for Preparation Click here

## DESCRIPTION

1. A thermistor is built into the Engine Coolant Temperature (ECT) sensor and changes the resistance value according to the engine coolant temperature.
   The structure of the sensor and its connection to the ECM is the same as that of the Intake Air Temperature (IAT) sensor and its connection.

   HINT:
     If the ECM detects DTC P0115, P0117 or P0118, the ECM enters fail-safe mode, in which the ECT is assumed to be 80°C (176°F).

DTC No. | Proceed to | DTC Detection Condition | Trouble Area

P0115

Open or short in intake air temperature sensor circuit for 0.5 seconds

Open or short in ECT sensor circuit for 0.5 seconds

1. Open or short in ECT sensor circuit
2. ECT sensor
3. ECM

P0117

Short in intake air temperature sensor circuit for 0.5 seconds

Short in ECT sensor circuit for 0.5 seconds

1. Short in ECT sensor
2. ECT sensor
3. ECM

P0118

Open in intake air temperature sensor circuit for 0.5 seconds

Open in ECT sensor circuit for 0.5 seconds

1. Open in ECT sensor circuit
2. ECT sensor
3. ECM

HINT:

  When DTC P0115, P0117 or P0118 is detected, check the engine coolant temperature by entering the following menus on the intelligent tester: Powertrain / Engine and ECT / Data List / Coolant Temp.

Temperature Displayed | Malfunction
-40°C (-40°F) | Open circuit
120°C (248°F) or more | Short circuit

## MONITOR DESCRIPTION

The Engine Coolant Temperature (ECT) sensor is used to monitor the ECT. The ECT sensor has a thermistor that varies its resistance depending on 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. The 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:
When the ECM calculates that the ECM is -40°C (-40°F) (P0118) or more than 120°C (248°F) (P0117) and that the either condition continues for 0.5 seconds or more, the ECM will set a DTC.
This monitor runs for 0.5 seconds after the ignition switch is turned ON (1 trip detection logic).
If the malfunction is not repaired successfully, a DTC is set 0.5 seconds after the next time the engine is started.

## WIRING DIAGRAM

## INSPECTION PROCEDURE

1. If DTCs related to different systems that have terminal E2 as the ground terminal are output simultaneously, terminal E2 may have an open circuit.
2. Read freeze frame data using the intelligent tester. Freeze frame data records the engine conditions when a malfunction is detected. When troubleshooting, freeze frame data can help determine if the vehicle was running or stopped, 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

1. Connect the intelligent tester to the DLC3.

1. Turn the ignition switch ON and turn the tester ON.

1. Enter the following menus: Powertrain / Engine and ECT / DTC.

1. Read DTCs.

Result:

  Display (DTC Output) | Proceed To
  P0110 | A
  P0112 | B
  P0113 | C

| B |

Go to step 5

| C |

Go to step 3

A |

2.READ DATA LIST (ENGINE COOLANT TEMPERATURE)

1. Connect the intelligent tester to the DLC3.

1. Turn the ignition switch ON and turn the tester ON.

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

1. Read the values.

   OK:
     Temperature value is 80 to 97°C (176 to 207°F) after warming up engine.

   Result:

     Temperature Displayed | Proceed to
     -40°C (-40°F) | A
     120°C (248°F) or more | B
     OK (same as the actual engine coolant temperature) | C

   HINT:
   1. If there is an open circuit, the tester indicates -40°C (-40°F).
   2. If there is a short circuit, the tester indicates 120°C (248°F) or more.

| B |

Go to step 5

| C |

CHECK FOR INTERMITTENT PROBLEMS

A |

3.READ DATA LIST (CHECK FOR OPEN IN WIRE HARNESS)

1. Disconnect the W1 ECT sensor connector.

1. Connect terminals 1 and 2 of the W1 ECT sensor wire harness side connector.

1. Connect the intelligent tester to the DLC3.

1. Turn the ignition switch ON and turn the tester ON.

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

1. Read the value.

   OK:
     Temperature value is 120°C (248°F) or more

| OK |

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

NG |

4.READ DATA LIST (CHECK FOR OPEN IN ECM)

1. Disconnect the W1 ECT sensor connector.

1. Connect terminals THW and E2 of the E15 ECM wire harness connector.

   HINT:
     Before checking, perform a visual and contact pressure check on the ECM connector.

1. Connect the intelligent tester to the DLC3.

1. Turn the ignition switch ON and turn the tester ON.

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

1. Read the value.

   OK:
     Temperature value is 120°C (248°F) or more

| OK |

REPAIR OR REPLACE HARNESS AND CONNECTOR

NG |

CONFIRM GOOD CONNECTION AT ECM. IF OK, REPLACE ECM

5.READ DATA LIST (CHECK FOR SHORT IN WIRE HARNESS)

1. Disconnect the W1 ECT sensor connector.

1. Connect the intelligent tester to the DLC3.

1. Turn the ignition switch ON and turn the tester ON.

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

1. Read the value.

   OK:
     Temperature value is -40°C (-40°F)

| OK |

REPLACE ENGINE COOLANT TEMPERATURE

NG |

6.READ DATA LIST (CHECK FOR SHORT IN ECM)

1. Disconnect the W1 ECT sensor connector.

1. Disconnect the E15 ECM connector.

1. Connect the intelligent tester to the DLC3.

1. Turn the ignition switch ON and turn the tester ON.

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

1. Read the value.

   OK:
     Temperature value is -40°C (-40°F)

| OK |

REPAIR OR REPLACE HARNESS AND CONNECTOR

NG |

REPLACE ECM