P0117 Coolant Temperature Sensor Circuit Input Low

P0117 – OBD-II Trouble Code Technical Description

Trouble code P0117 is a general trouble code that indicates that the engine control module (ECM) has detected the coolant temperature sensor circuit voltage is too low (less than 0,14 V).

What does the fault code mean P0117?

Trouble code P0117 indicates a problem with the engine coolant temperature sensor. This code indicates that the signal coming from the coolant temperature sensor is outside the expected range of values.

Possible reasons

Some possible causes of the P0117 trouble code:

• Defective coolant temperature sensor.
• The wiring or connectors connecting the sensor to the ECU (electronic control unit) may be damaged or broken.
• Incorrect signals from the sensor caused by corrosion or contamination.
• Electrical problems in the cooling system, such as an open or short circuit.
• An error in the operation of the ECU itself, possibly due to a software failure or damage.

What are the symptoms of a fault code? P0117?

The following are possible symptoms if DTC P0117 is present:

• Engine roughness: The vehicle may jerk or lose power due to the engine management system not working properly.
• Increased fuel consumption: Incorrect signals from the temperature sensor can lead to an incorrect mixture of air and fuel, which increases fuel consumption.
• Starting Problems: The vehicle may have difficulty starting or may not start at all in cold weather due to incorrect coolant temperature information.
• Cooling system instability: Incorrect temperature information can cause the cooling system to malfunction, which can cause engine overheating or other cooling problems.
• Erroneous instrument panel displays: Error messages or indicators may appear related to engine temperature or cooling system.

How to diagnose a fault code P0117?

To diagnose trouble code P0117, follow these steps:

• Check Coolant Temperature (ECT) Sensor:
  • Check the ECT sensor connections for corrosion, oxidation, or poor connections.
  • Use a multimeter to test the resistance of the ECT sensor at different temperatures. Compare the measured resistance to the technical specifications for your specific vehicle.
  • Check the wiring from the ECT sensor to the engine control module (ECM) for opens or shorts.
• Check the power and ground circuit:
  • Check the supply voltage at the ECT sensor terminals with the ignition on. The voltage must be within the manufacturer's specifications.
  • Verify that the signal circuit between the ECT sensor and the ECM is functioning properly. Check for corrosion or breaks.
• Check the coolant temperature sensor itself:
  • If all electrical connections are good and the signal from the ECT sensor is not as expected, the sensor itself may be faulty and needs to be replaced.
• Check Engine Control Module (ECM):
  • If there are no other problems, and if the ECT sensor and its power circuit are normal, the problem may be in the ECM. However, this is a rare occurrence and the ECM should only be replaced after a thorough diagnosis.
• Use a diagnostic scanner:
  • Use a scan tool to check for other trouble codes that may be related to the coolant temperature sensor or cooling system.

After following these steps, you will be able to identify the cause and repair the problem that is causing the P0117 code. If you experience difficulty or are unsure of your skills, it is recommended that you contact a qualified auto mechanic for further diagnosis and repair.

Diagnostic errors

When diagnosing trouble code P0117 (incorrect coolant temperature sensor signal), the following errors may occur:

• Misinterpretation of symptoms: Some symptoms, such as engine heating problems or abnormal engine operation, may be due to problems other than improper coolant temperature. Misinterpretation of symptoms can lead to misdiagnosis and replacement of unnecessary parts.
• Insufficient wiring check: Incorrect connection or broken wiring between the coolant temperature sensor and the engine control module (ECM) can cause P0117. Insufficient wiring inspection may result in misdiagnosis and malfunction.
• Temperature sensor incompatibility: Some coolant temperature sensors may not be compatible with engine temperature characteristics. This may result in an incorrect temperature reading and cause P0117.
• Non-compliance with standards: Poor quality or non-standard coolant temperature sensors may cause a P0117 code due to their malfunction or failure to meet manufacturer standards.
• Incorrect ECM diagnosis: In rare cases, the problem may be with the Engine Control Module (ECM) itself. However, replacing the ECM should only be done after a thorough diagnosis and exclusion of other possible causes of the P0117 code.

To successfully diagnose and resolve P0117, it is recommended to use a systematic approach, checking every possible source of the problem and eliminating possible errors

How serious is the fault code? P0117?

Trouble code P0117, indicating an incorrect coolant temperature sensor signal, can be considered quite serious. The inability of the ECU (engine control module) to obtain correct coolant temperature data can lead to a number of problems:

• Insufficient engine efficiency: Incorrect reading of coolant temperature can result in improper control of the fuel injection system and ignition timing, which reduces engine efficiency.
• Increase in emissions: Incorrect coolant temperature can cause uneven fuel combustion, which increases emissions and pollution.
• Increased risk of engine damage: If the engine is insufficiently cooled or overheated, there may be a risk of damage to engine components such as the cylinder head, gaskets and other important components.
• Loss of power and efficiency: Improper engine management can result in loss of power and poor fuel economy.

Therefore, although the P0117 code is not an emergency, it should be considered a serious problem that requires immediate attention and diagnosis to prevent possible engine damage and ensure proper engine operation.

What repair will help eliminate the code? P0117?

To resolve DTC P0117, follow these steps:

• Checking the coolant temperature (ECT) sensor: Check the sensor for corrosion, damage or broken wiring. Replace the sensor if necessary.
• Checking electrical connections: Check the electrical connections, including connectors and wiring associated with the coolant temperature sensor. Make sure the connections are secure and there is no damage.
• Cooling system check: Check the condition of the cooling system, including coolant level and condition, leaks, and thermostat functionality. Make sure the cooling system is functioning properly.
• Checking the Engine Control Module (ECM): Check the ECM for corrosion or damage. Replace the ECM if necessary.
• Resetting the error code: After repairing, clear the error code using a diagnostic scanner or disconnect the negative battery terminal for a while.
• Rigorous testing: After completing the repair and resetting the error code, test the vehicle thoroughly to ensure that the problem is resolved.

If you are unsure of your skills or do not have the necessary equipment, it is recommended that you contact a qualified auto mechanic or auto repair shop for diagnosis and repair.

Causes and Fixes P0117 Code: Engine Coolant Temperature Sensor 1 Circuit Low

P0117 – Brand-specific information

Some interpretations of the P0117 fault code for various car brands:

1. Volkswagen (VW):
   • P0117 – Coolant temperature sensor, circuit low.
2. Toyota:
   • P0117 – Coolant Temperature Sensor, Input Circuit Low.
3. Ford:
   • P0117 – Coolant temperature sensor, signal out of range.
4. Chevrolet (Chevy):
   • P0117 – Low signal from the coolant temperature sensor.
5. Honda:
   • P0117 – Coolant temperature sensor, low level input.
6. Nissan:
   • P0117 – Coolant Temperature Sensor, Input Circuit Low.
7. BMW:
   • P0117 – Coolant temperature sensor, signal out of range.
8. Mercedes-Benz:
   • P0117 – Coolant temperature sensor, signal out of range.

These are just some of the possible explanations for the P0117 trouble code. The exact value may vary depending on the model and year of the vehicle. For more accurate information, it is recommended to consult the official repair manual for your specific vehicle or contact a professional auto repair shop.