QuestionI have a 2001 hyundai sonata I keep getting code p0115 it comes up as a trouble code it also comes up as a pending code the code stands for engine coolant temp circuit malfunction. what does this mean and how can it be repaired?
Answer SERVICE MANUAL
Applies to: Sonata 2001
GROUP
Fuel System Troubleshooting
DTC P0115
DTC
Diagnostic Item
P0115
Engine coolant Temperature Circuit Malfunction
DESCRIPTION
The engine coolant temperature (ECT) sensor is located in the coolant passage of the cylinder head. The ECT sensor is a variable resistor whose resistance changes as the temperature of the engine coolant flowing past the sensor changes. When coolant temperature is low, sensor resistance is high; when coolant temperature is high, sensor resistance is low. The engine control module (ECM) checks ECT voltage fifty times per second and uses the information to adjust fuel injector pulse width and ignition timing. When the temperature sensed is very cold, the ECM enriches the fuel mixture.
TROUBLESHOOTING GUIDE
DTC detection condition Probable cause
Background
The engine coolant temperature sensor converts the engine coolant temperature to a voltage and outputs it.
The engine control module checks whether the voltage is within a specified range. In addition, it checks that the engine coolant temperature (signal) does not drop while the engine is warming up.
Check area, Judgment Criteria
Sensor output voltage has continued to be 4.6V or higher [corresponding to a coolant temperature of -45°C (-49°F) or lower] for 4 sec.
Sensor output voltage has continued to be 0.1V or lower [corresponding to a coolant temperature of 140°C (284°F) or higher] for 4 sec.
Check area, Judgment Criteria
Sensor output voltage increased from a value lower than 1.6V to a value higher than 1.6V [Coolant temperature decreases from a higher than 40°C (104°F) temperature to a lower than 40°C (104°F) temperature.].
Then the sensor output voltage has continued to be 1.6V or higher for 5 min.
Check area
The engine coolant temperature is approx. 40°C (104°F) or less after starting sequence is completed.
Judgment Criteria
Approx. 60 - 300 seconds have passed for the engine coolant temperature to rise to about 40°C (104°F) after starting sequence was completed.
Engine coolant temperature sensor failed
Open or shorted engine coolant temperature sensor circuit, or loose connector
Engine control module failed
