P0181

DTC P0181 - FUEL TEMPERATURE SENSOR "A" CIRCUIT RANGE/PERFORMANCE

OUTLINE OF DIAGNOSIS
Detect the malfunction of fuel temperature sensor output property.
Diagnosis is performed in two methods; namely, drift diagnosis and stuck diagnosis.




COMPONENT DESCRIPTION
- Drift Diagnosis
Normally fuel temperature is lower than engine coolant temperature. When the fuel temperature becomes higher than the engine coolant temperature, the range is considered to be shifted, and NG judgment is done.




ENABLE CONDITION

GENERAL DRIVING CYCLE
Perform the diagnosis continuously when the engine coolant temperature increases more than -8 degrees (18 degrees of Fahrenheit) from the temperature of engine starting in 20 seconds after starting the engine.

DIAGNOSTIC METHOD




Judge NG when the continuous time until completing the malfunction criteria becomes more than the time (120 seconds) needed for diagnosis. Also, judge OK when the malfunction criteria is not completed. And then, clear the NG.

- Stuck Diagnosis
If the fuel temperature which must increase along with engine idling does not increase, the engine is considered to be stuck and NG judgment is done.




ENABLE CONDITION

GENERAL DRIVING CYCLE
Perform the diagnosis continuously in 20 seconds and more after starting the engine.

DIAGNOSTIC METHOD




- Abnormality Judgment
Judge NG when all of the malfunction criteria is completed.




- Normality Judgment
Judge OK and clear the NG when the malfunction criteria are completed.

DTC CLEAR CONDITION
- When the OK idling 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
Fix the fuel temperature at 40 °C (104 °F).

ECM OPERATION AT DTC SETTING
Memorize the freeze frame data. (For test mode $02)