P0118
DTC P0118 ENGINE COOLANT TEMPERATURE CIRCUIT HIGH INPUTComponent 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 (ECM). The ECM/PCM applies 5 volts to the ECT sensor. The ECM/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 ECM/PCM will receive a high voltage input, and when the engine is warm the ECM/PCM will receive a low voltage input. The signal from ECT sensor is used for Injection control, ignition timing, idle speed and cooling fan control.
DTC DESCRIPTION
If measured temperature is lower than the minimum threshold value, ECM/PCM sets DTC P0118.(In this case, the input signal voltage is the maximum threshold value.)
DTC Detecting Condition:
SPECIFICATION
Refer to DTC P0115.
Schematic Diagram [AT]:
Schematic Diagram [MT]:
MONITOR SCANTOOL DATA
1. Connect scantool to DLC (Data Link Cable).
2. Warm up the engine to normal operating temperature.
3. Monitor "ECTS" parameter on scantool.
4. Is the "ECTS" parameter displayed correctly?
YES
- Case1] This DTC can caused by Intake Air Temperature Sensor (IATS). So, if there is (are) DTC(s) of IATS, refer to IATS's DTC Guide.
- Case2] Fault is intermittent caused by poor contact in the sensor's and/or ECM/PCM's connector was repaired and ECM/PCM memory was not cleared. Thoroughly check connectors for looseness, poor connection, ending, corrosion, contamination, deterioration, or damage. Repair or replace as necessary and go to "Verification of Vehicle Repair" procedure.
NO - Go to "Terminal & Connector Inspection" procedure.
TERMINAL AND CONNECTOR INSPECTION
1. Many malfunctions in the electrical system are caused by poor harness and terminal condition. Faults can also be caused by interference from other electrical systems, and mechanical or chemical damage.
2. Thoroughly check connectors for looseness, poor connection, bending, corrosion, contamination, deterioration, or damage.
3. Has a problem been found?
YES - Repair as necessary and go to "Verification of vehicle Repair" procedure.
NO - Go to "Voltage Inspection " procedure.
SIGNAL CIRCUIT INSPECTION
1. IG "OFF".
2. Disconnect ECTS connector.
3. IG "ON" & ENG "OFF"
4. Measure voltage between terminal 1 of ECTS harness connector and chassis ground.
5. Is the measured voltage within specification?
YES - Go to "Ground Circuit Inspection" procedure.
NO - Repair or replace as necessary and then, go to "Verification of Vehicle Repair" procedure.
GROUND CIRCUIT INSPECTION
1. IG "OFF".
2. Disconnect ECTS connector.
3. IG "ON" & ENG "OFF"
4. Measure voltage between terminal 1 of ECTS harness connector and chassis ground. (A)
5. Measure voltage between terminal 1 and 3 of ECTS harness connector. (B)
Specification : "A" - "B" = Below 200 mV
6. Is the measured voltage within specification?
YES - Go to "Component Inspection" procedure.
NO - Repair or replace as necessary and then, go to Verification of Vehicle Repair" procedure.
COMPONENT INSPECTION
1. Check ECTS resistance.
1. IG "OFF".
2. Disconnect ECTS connector.
Specification:
3. Measure resistance between terminal 1 and 3 of ECTS harness connector. (Component Side)
4. Is the measured resistance within specification?
YES - Go to "Check ECM/PCM" as follows.
NO
- Substitute with a known - good ECTS and check for proper operation.
- If the problem is corrected, replace ECTS and go to "Verification of Vehicle Repair" procedure.
2. Check ECM/PCM
1. IG "OFF" and disconnect ECTS connector.
2. Connect scantool and Key "ON"
3. Select simulation function on scantool.
4. Simulate voltage at terminal 1 of ECTS signal connector.
5. Does the signal value of ECTS change according to simulation voltage?
YES - Thoroughly check connectors for looseness, poor connection, bending, corrosion, contamination, deterioration, or damage. Repair or replace as necessary and go to "Verification of Vehicle Repair" procedure.
NO
- Substitute with a known - good ECM/PCM and check for proper operation.
- If the problem is corrected, replace ECM/PCM and 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 scan tool and select "Diagnostic Trouble Codes (DTCs)" mode.
2. Clear the DTCs and Operate the vehicle within DTC Enable conditions in General information.
3. Are any DTCs present?
YES - Go to the applicable troubleshooting procedure.
NO - System is performing to specification at this time.