Dtc P0116 Engine Coolant Temperature Circuit Range / Performance Problem

DESCRIPTION

MONITOR DESCRIPTION

MONITOR STRATEGY

TYPICAL ENABLING CONDITIONS

TYPICAL MALFUNCTION THRESHOLDS

COMPONENT OPERATING RANGE

CONFIRMATION DRIVING PATTERN

INSPECTION PROCEDURE

CHECK ANY OTHER DTCS OUTPUT (IN ADDITION TO DTC P0116)

READ VALUE USING TECHSTREAM (COOLANT TEMP)

INSPECT THERMOSTAT

DESCRIPTION

MONITOR DESCRIPTION

1. Engine coolant temperature (ECT) sensor cold start monitor
   The monitor runs when the engine is started cold. If the change in engine coolant temperature sensor output until the engine warmed up completely is less than the threshold, it is determined that a malfunction has occurred in the engine coolant temperature sensor. When this is detected in 2 consecutive driving cycles, the MIL is illuminated and the DTC is stored.
   

1. ECT sensor soak monitor
   The ECM compares the engine coolant temperature when the warmed engine is stopped and when the engine is started on the next trip when more than 5 hours has elapsed since the engine was stopped. If the change in engine coolant temperature sensor output is less than the threshold, it is determined that a malfunction has occurred in the engine coolant temperature sensor. When this is detected in 2 consecutive driving cycles, the MIL is illuminated and the DTC is stored.
   

MONITOR STRATEGY

TYPICAL ENABLING CONDITIONS

TYPICAL MALFUNCTION THRESHOLDS

COMPONENT OPERATING RANGE

CONFIRMATION DRIVING PATTERN

1. Connect the Techstream to the DLC3.
   
2. Turn the ignition switch to ON and turn the Techstream on.
   
3. Enter the following menu items: Powertrain / Engine and ECT / Data List / Coolant Temp.
   
4. Check that the coolant temperature is 60°C (140°F) or less.
   
5. Clear DTCs (even if no DTCs are stored, perform the clear DTC operation).
   
6. Turn the ignition switch off and wait for at least 30 seconds.
   
7. Turn the ignition switch to ON and turn the Techstream on [A].
   
8. Start the engine and idle it for 5 minutes or more [B].
   

   HINT:

   If the engine coolant temperature does not change by 5°C (9°F) or higher, the ECT sensor is malfunctioning. It is not necessary to continue this procedure.

9. Enter the following menus: Powertrain / Engine and ECT / Trouble Codes [C].
   
10. Read pending DTCs.
    

    HINT:

    1. If a pending DTC is output, the system is malfunctioning.
       
    2. If a pending DTC is not output, perform the following procedure.
       
11. Enter the following menus: Powertrain / Engine and ECT / Utility / All Readiness.
    
12. Input the DTC: P0116.
    
13. Check the DTC judgment result.
    
    

    Techstream 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

    HINT:

    1. If the judgment result shows NORMAL, the system is normal.
       
    2. If the judgment result shows ABNORMAL, the system has a malfunction.
       
    3. If the judgment result shows INCOMPLETE or N/A, perform steps [D] and [E].
       
14. Drive the vehicle at 40 km/h (25 mph) or more for a total of 5 minutes or more [D].
    

    CAUTION:

    When performing the confirmation driving pattern, obey all speed limits and traffic laws.

    HINT:

    In the event of the drive pattern being interrupted (possibly due to factors such as traffic conditions), the drive pattern can be resumed.

15. Check the DTC judgment result again [E].
    

    HINT:

    If the judgment result shows INCOMPLETE or N/A, perform steps [D] and [E] again.

16. If no pending DTC is output, perform a universal trip and check for permanent DTCs (YARIS_NCP93 RM000000PDK0QGX.html).
    

    HINT:

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

INSPECTION PROCEDURE

HINT:

1. If any of DTCs P0115, P0117, P0118, P0125 or P0128 are stored simultaneously with DTC P0116, the ECT sensor circuit may have an open or a short circuit.
   
2. Read freeze frame data using the Techstream. The ECM records vehicle and driving condition information as freeze frame data the moment a DTC is stored. 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. Connect the Techstream to the DLC3.
   

2. Turn the ignition switch to ON.
   

3. Turn the Techstream on.
   

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

5. Read DTCs.
   

1. Connect the Techstream to the DLC3.
   

2. Turn the ignition switch to ON.
   

3. Turn the Techstream on.
   

4. Clear DTCs (YARIS_NCP93 RM000000PDK0QGX.html).
   

5. Turn the ignition switch off and wait for at least 30 seconds.
   

6. Turn the ignition switch to ON.
   

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

8. Read the values displayed on the Techstream while wiggling the ECM wire harness.
   

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

10. Read DTCs.
    

    Result

    Result	Proceed to
    Value in Data List changes when wire harness is wiggled, or DTC is output*	B
    Other than above	A

    *: As the DTC was stored due to a change in the contact resistance of the connector, repair or replace the wire harness or connector (YARIS_NCP93 RM000000UZ309WX.html).
    

    HINT:

    Check that the actual engine coolant temperature and the Coolant Temp value displayed on the Techstream are approximately equal. If the Coolant Temp value is lower than the actual, check the connector connections between the ECM and the engine coolant temperature sensor.

1. Remove the thermostat (YARIS_NCP93 RM000001DGA00ZX.html).
   

2. Check the valve opening temperature of the thermostat.
   

   Standard Value:

   80°C to 84°C (176°F to 183°F)
   

   HINT:

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

3. Reinstall the thermostat (YARIS_NCP93 RM000001DG700ZX.html).