P0118
DTC PO118 ENGINE COOLANT TEMPERATURE CIRCUIT HIGH INPUTComponent Location:
GENERAL DESCRIPTION
The Engine Coolant Temperature Sensor (ECTS) is located in the engine coolant passage of the cylinder head for detecting the engine coolant temperature. The ECTS uses a thermistor whose resistance changes with the temperature. The electrical resistance of the ECTS decreases as the temperature increases, and increases as the temperature decreases. The reference 5 V in the ECM is supplied to the ECTS via a resistor in the ECM. That is, the resistor in the ECM and the thermistor in the ECTS are connected in series. When the resistance value of the thermistor in the ECTS changes according to the engine coolant temperature, the output voltage also changes. During cold engine operation the ECM increases the fuel injection duration and controls the ignition timing using the information of engine coolant temperature to avoid engine stalling and improve DRIVEABILITY.
DTC DESCRIPTION
ECM sets DTC P0118 if the ECM detects signal voltage higher than the possible range of a properly operating ECTS.
DTC Detecting Condition:
Specification:
Schematic Diagram:
MONITOR DTC STATUS
NOTE: If any DTCs relating to ECTS are stored, do ALL REPAIRS associated with those codes before proceeding with further troubleshooting
1. Connect scan tool and select "Diagnostic Trouble Codes (DTCs)" mode.
2. Press F4 (DTAL) to select DTC information from the DTCs menu.
3. Confirm that "DTC Readiness Flag" indicates "Complete". If not, drive the vehicle within conditions noted in the freeze frame data or enable conditions.
4. Read "DTC Status" parameter.
5. Is parameter displayed "History (Not Present) fault"?
NOTE:
- History (Not Present) fault : DTC occurred but has been cleared.
- Present fault : DTC is occurring at present time.
YES - Fault is intermittent caused by poor contact in the sensor's and/or ECM's connector or was repaired and ECM memory was not cleared. Thoroughly Check connectors for looseness, poor connections, bending, corrosion, contamination, deterioration, or damage. Repair or replace as necessary and then go to "Verification of Vehicle Repair" procedure
NO - Go to next step as below.
GROUND CIRCUIT INSPECTION
1. Ignition "OFF".
2. Disconnect ECTS connector.
3. Measure resistance between terminals 3 of the sensor harness connector and chassis ground.
Specification : Approx. 0 ohm
4. IS resistance within the specification?
YES - Go to "Terminal and connector Inspection" procedure
NO - Repair open circuit and go to "Verification of Vehicle Repair" procedure
SIGNAL CIRCUIT INSPECTION
1. Check for short to battery in signal harness
1. Disconnect ECM connector.
2. Ignition "ON" & Engine "OFF".
3. Measure voltage between terminal 1 of the sensor harness connector and chassis ground.
Specification : Approx. 0 V
4. Is voltage within the specification?
YES - Go to "Terminal and Connector Inspection" procedure
NO - Check for short to battery or open in signal harness. Repair as necessary and go to "Verification of Vehicle Repair" procedure.
2. Check for open in signal harness
1. Ignition "OFF".
2. Measure voltage between terminal 1 of the sensor harness connector and 15 of the ECM harness connector.
Specification : Approx. 0 ohm
3. Is resistance within the specification?
YES - Go to next step as below
NO - Check for open In signal harness. Repair as necessary and go to "Verification of Vehicle Repair" procedure.
TERMINAL AND CONNECTOR INSPECTION
1. Many malfunctions in the electrical system are caused by poor harness(es) and terminals. 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 - Check for poor connection between ECM and component : backed out terminal, improper mating, broken locks or poor terminal to wire connection. Repair as necessary and go to "Verification of Vehicle Repair" procedure.
COMPONENT INSPECTION
Specification:
1. Measure resistance between terminals 1 and 3 of the sensor connector (Component side)
2. Is resistance within the specification?
YES - Check for poor connection between ECM and component: backed out terminal, improper mating, broken locks or poor terminal to wire connection. Repair as necessary and go to "Verification of Vehicle Repair" procedure
NO - Check ECTS for contamination, deterioration, or damage. Substitute with a known-good ECTS and Check for proper operation. If the problem is corrected, replace ECTS and then 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. 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.