DTC P0117: Engine Coolant Temperature Circuit Low Input

OUTLINE OF DIAGNOSIS
Detect the open or short circuit of engine coolant temperature sensor.

Judge NG when out of the standard value.
COMPONENT DESCRIPTION

Fig 1: Engine Coolant Temperature Sensor Cross Sectional View And Temperature-Resistance Graph
Courtesy of SUBARU OF AMERICA, INC.

ENABLE CONDITION

ENABLE CONDITIONS

Secondary Parameters	Enable Conditions
None

GENERAL DRIVING CYCLE
Always perform the diagnosis continuously.

DIAGNOSTIC METHOD

Judge NG when the continuous time until completing the malfunction criteria below becomes more than the time (2.5 seconds) needed for diagnosis.

Judge fail safe NG when the continuous time until completing the malfunction criteria below becomes more than the time (0.2 seconds) needed for diagnosis. Judge OK and clear the NG when the malfunction criteria below are not completed.

Judgment Value

JUDGMENT VALUE

Malfunction Criteria	Threshold Value
Output voltage	"LESS THAN EQUAL TO" 0.1 V

Time Needed for Diagnosis: 2.5 seconds

Malfunction Indicator Light Illumination: Illuminates as soon as malfunction occurs.

DTC CLEAR CONDITION
- When the OK idling cycle was completed 40 times in a row
- When "Clear Memory" was performed
MALFUNCTION INDICATOR LIGHT CLEAR CONDITION
- When the OK driving cycle was completed 3 times in a row
- When "Clear Memory" was performed
FAIL SAFE
Keep the engine coolant temperature at 70°C (158°F).
ECM OPERATION AT DTC
Memorize the freeze frame data. (For test mode $02)