P0115
DTC P0115 ENGINE COOLANT TEMPERATURE CIRCUITComponent Location:
GENERAL DESCRIPTION
The Engine Coolant Temperature (ECT) Sensor measures the temperature of engine coolant. The Engine Coolant Temperature (ECT) Sensor is located near the thermostat housing of the cylinder head. ECT Sensor is a thermistor (A Variable Resistor that Changes Along with ECT) in series with a fixed resistor in the Engine Control Module (PCM). The PCM applies 5 volts to the ECT sensor. The PCM monitors the voltage across the ECT sensor and converts it into a temperature reading. When the engine is cold the ECT sensor resistance is high, and when the engine is warm the ECT sensor resistance is low. Therefore, when the engine is cold the PCM will receive a high voltage input, and when the engine is warm the PCM will receive a low voltage input. The signal from ECT sensor is used for Injection, ignition timing, idle speed and cooling fan control.
DTC DESCRIPTION
Checking the engine coolant temperature under detecting condition, if if the difference between its current temperature and startup temperature is less than threshold value over predeterminated period, PCM sets P0115. MIL (Malfunction Indication Lamp) turns on when the malfunction lasts till consecutive 2 driving cycle.
DTC Detecting Condition:
Specification:
Schematic Diagram:
Signal Waveform And Data:
SIGNAL WAVEFORM AND DATA
The output signals of IATS & ECTS change smoothly without any rapid changes. Those have almost same characteristic signal during the early period after start. It means that the temperatures of intake air and engine coolant are depended on the temperature of atmosphere. Meanwhile, during the warming up, the output signal of ECTS is going up increasingly.But, the output signal of IATS changes a little bit. Even it may not change almost. It means that the heat of engine does not affect on the temperature of intake air.
MONITOR SCANTOOL DATA
1. Connect scantool to Data Link Connector (DLC).
2. IG "ON".
3. Select "Diagnostic Trouble Codes (DTCs)" mode, and then Press F4 (DTAL) to check DTC's information from the DTCs menu.
4. Read "DTC Status" parameter.
5. Is parameter displayed "Present fault"?
YES - Go to "Component Inspection" procedure.
NO - Fault is intermittent, go to "Verification of vehicle Repair" procedure.
COMPONENT INSPECTION
1. IG "OFF" and disconnect ECTS connector.
2. Remove it.
Specification:
3. Measure resistance between terminals 1 and 3 of ECTS connector as the temperature rises.
4. Are the measured resistance within specification?
YES - Clear DTC and Test-drive under enable conditions above-mentioned. After the test, If this DTC is set, recheck it thoroughly. If not, it is intermittent fault, go to "Verification of vehicle Repair" procedure.
NO - Substitute with a known - good ECTS and check for proper operation. If the problem is corrected, Go to "Verification of Vehicle Repair" procedure.
VERIFICATION OF VEHICLE REPAIR
After a repair, it is essential to verify that the fault has been corrected.
1. Connect scantool and select "Diagnostic Trouble Codes (DTCs)" mode
2. Press F4 (DTAL) and confirm that "DTC Readiness Flag" indicates "Complete". If not, drive the vehicle within conditions noted in the freeze frame data or enable conditions.
3. Read "DTC Status" parameter.
4. Is parameter displayed "History (Not Present) fault"?
YES - System performing to specification at this time. Clear the DTC
NO - Go to the applicable troubleshooting procedure.