SFI SYSTEM, Diagnostic DTC:P0115, P0117, P0118

DTC Code	DTC Name
P0115	Engine Coolant Temperature Circuit
P0117	Engine Coolant Temperature Circuit Low Input
P0118	Engine Coolant Temperature Circuit High Input

DESCRIPTION

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.

Tech Tips

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	Open or short in ECT sensor circuit ECT sensor ECM
P0117	Short in intake air temperature sensor circuit for 0.5 seconds	Short in ECT sensor circuit for 0.5 seconds	Short in ECT sensor circuit ECT sensor ECM
P0118	Open in intake air temperature sensor circuit for 0.5 seconds	Open in ECT sensor circuit for 0.5 seconds	Open in ECT sensor circuit ECT sensor ECM

Tech Tips

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

If DTCs related to different systems that have terminal E2 as the ground terminal are output simultaneously, terminal E2 may have an open circuit.
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.

PROCEDURE

READ OUTPUT DTC

Connect the intelligent tester to the DLC3.
Turn the ignition switch ON and turn the tester ON.
Enter the following menus: Powertrain / Engine and ECT / DTC.

Read DTCs.

Result

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

READ VALUE USING INTELLIGENT TESTER (CHECK FOR SHORT IN WIRE HARNESS) Click here

READ VALUE USING INTELLIGENT TESTER (CHECK FOR OPEN IN WIRE HARNESS) Click here

READ VALUE USING INTELLIGENT TESTER (ENGINE COOLANT TEMPERATURE)

Connect the intelligent tester to the DLC3.
Turn the ignition switch ON and turn the tester ON.
Enter the following menus: Powertrain / Engine and ECT / Data List / Coolant Temp.

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

Tech Tips

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

READ VALUE USING INTELLIGENT TESTER (CHECK FOR SHORT IN WIRE HARNESS) Click here

CHECK FOR INTERMITTENT PROBLEMS

READ VALUE USING INTELLIGENT TESTER (CHECK FOR OPEN IN WIRE HARNESS)
1. Disconnect the W1 ECT sensor connector.
2. Connect terminals 1 and 2 of the W1 ECT sensor wire harness side connector.
3. Connect the intelligent tester to the DLC3.
4. Turn the ignition switch ON and turn the tester ON.
5. Enter the following menus: Powertrain / Engine and ECT / Data List / Coolant Temp.
6. 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
READ VALUE USING INTELLIGENT TESTER (CHECK FOR OPEN IN ECM)
1. Disconnect the W1 ECT sensor connector.
2. Connect terminals THW and E2 of the E15 ECM wire harness connector.
  
  Tech Tips
  
  Before checking, perform a visual and contact pressure check on the ECM connector.
3. Connect the intelligent tester to the DLC3.
4. Turn the ignition switch ON and turn the tester ON.
5. Enter the following menus: Powertrain / Engine and ECT / Data List / Coolant Temp.
6. 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
READ VALUE USING INTELLIGENT TESTER (CHECK FOR SHORT IN WIRE HARNESS)
1. Disconnect the W1 ECT sensor connector.
2. Connect the intelligent tester to the DLC3.
3. Turn the ignition switch ON and turn the tester ON.
4. Enter the following menus: Powertrain / Engine and ECT / Data List / Coolant Temp.
5. Read the value.
  
  OK
  
  Temperature value is -40°C (-40°F)
OK
REPLACE ENGINE COOLANT TEMPERATURE SENSOR

NG
READ VALUE USING INTELLIGENT TESTER (CHECK FOR SHORT IN ECM)
1. Disconnect the W1 ECT sensor connector.
2. Disconnect the E15 ECM connector.
3. Connect the intelligent tester to the DLC3.
4. Turn the ignition switch ON and turn the tester ON.
5. Enter the following menus: Powertrain / Engine and ECT / Data List / Coolant Temp.
6. Read the value.
  
  OK
  
  Temperature value is -40°C (-40°F)
OK
REPAIR OR REPLACE HARNESS AND CONNECTOR

NG

REPLACE ECM