top of page
Tekniker

P0117 fault-error code (ECT) Coolant Temperature Circuit Low

Updated: Aug 26

P0117 fault-error code ECT Engine Coolant Temperature Circuit Low Input


P0117 fault-error code is an error code identified by the OBD-II (On-Board Diagnostics II) system and is associated with the ECT (Engine Coolant Temperature) sensor. This error code indicates that the ECT sensor is signaling low temperature.


P0117

What are the symptoms of P0117 Fault/Error Code?

 

Common signs or symptoms you may experience if you have a P0117 fault/error code are:

 

Check Engine Light: The Check Engine Light on the instrument cluster comes on, indicating that a malfunction has been detected by the Engine Control Module (ECM) or Engine Control Unit (ECU).



Incorrect Temperature Gauge: The temperature gauge on the dash may display inaccurate readings, show no reading at all, or fluctuate erratically.


Poor Engine Performance: You may notice poor engine performance, including rough idling, stalling, hesitation, or reduced fuel efficiency due to inaccurate temperature readings from the ECT sensor.


Hard Starting: Difficulty starting the engine, especially when cold, may be a symptom of a faulty ECT sensor providing inaccurate temperature readings.


Overheating or Cooling Problems: The engine may overheat or fail to reach optimum operating temperature due to incorrect temperature readings from the ECT sensor.



Transmission Shift Problems: Some vehicles use engine temperature data to adjust transmission shift points. Incorrect temperature readings can lead to erratic shifting, transmission slipping, or other transmission-related problems.


Poor Fuel Economy: An incorrect air-fuel mixture caused by a faulty ECT sensor can result in reduced fuel efficiency and increased fuel consumption.


Emissions Problems: Incorrect engine temperature readings can cause emissions to increase, potentially causing your vehicle to fail emissions tests.

 



What could be the reasons for the P0117 Fault/Error Code?

 

Common causes that may trigger the P0117 malfunction/error code include:

 

Defective ECT Sensor: The ECT sensor may be faulty and is providing a low or incorrect voltage signal to the ECM/ECU.


Open or Short Circuit: An open or short circuit in the wiring harness connecting the ECT sensor to the ECM/ECU.



Poor Electrical Connection: Loose, corroded, or damaged electrical connectors on the ECT sensor can lead to unreliable sensor readings and trigger a fault code.


Faulty ECU/ECM: In rare cases, the ECM/ECU may be faulty and may not be processing ECT sensor data correctly,


Coolant Level Problems: Low coolant level in the radiator and reservoir can affect ECT sensor readings and trigger a fault code.



Coolant Temperature Sensor Circuit Ground Problem: If there is a ground problem in the coolant temperature sensor circuit, it can cause erratic sensor readings and trigger a fault code.


Defective Radiator Fan: A defective radiator fan that is not operating properly can affect the engine's cooling system, causing incorrect temperature readings and triggering a fault code.


Wiring Harness Damage: Physical damage to the wiring harness, such as cuts, scrapes, or corrosion, can disrupt the ECT sensor circuit and trigger the fault code.


Faulty Thermostat: A faulty thermostat can cause the engine to run at incorrect temperatures.

 



What Steps Can Be Followed to Resolve the P0117 Fault/Error Code?

 

Here are the steps you need to follow to resolve the P0117 malfunction/error code:

 

Diagnostic Scan: Use an OBD-II scanner to retrieve the fault code and additional codes stored in the Engine Control Module (ECM) or Engine Control Unit (ECU). This will provide you with valuable information to pinpoint the problem.


Visual Review:

Check the ECT sensor for any visible signs of damage, corrosion or wear. Replace the sensor if it appears faulty.

Check the wiring harness and connectors for any damage, corrosion or loose connections. Repair or replace damaged components as necessary.



Test the ECT sensor:

Use a multimeter to test the voltage output of the ECT sensor. Check your vehicle's service manual for accurate voltage ratings at different temperatures.

If ECT sensor voltage values are not within the specified range, replace the sensor.


Check cables and connectors:

Test the continuity of the wiring harness using a multimeter to ensure there are no open or shorts.

Check connectors for proper pin connections and corrosion. Clean or replace worn connectors.



Check the coolant level:

Check the coolant level in the radiator and reservoir. If the coolant is low, fill it up and check for any leaks.

Make sure the coolant mixture is correct as specified by the manufacturer.


Check Thermostat Operation:

Test the thermostat to make sure it opens and closes properly. If the thermostat is faulty or stuck on/off, replace it.


Check Radiator Fan:

Check the operation of the radiator fan to ensure it is working properly. Replace the fan if it is not working as it should.



Reset ECM/ECU:

After making any necessary repairs or replacements, use the OBD-II scanner to clear the fault codes in the ECM/ECU memory.

Resetting the ECM/ECU will turn off the Check Engine Light and allow you to monitor if the problem is resolved.


Test Drive:

Take the vehicle for a test drive to monitor the engine's performance and make sure the temperature gauge is reading correctly.

Check if the fault code repeats or new problems may arise.



Last Inspection:

After the test drive, do a final inspection to ensure all repairs were completed correctly.

Double check all connections, sensors, and components related to the ECT sensor circuit.

 

What may be the long-term effects of the P0117 Fault/Error Code?

 

Some possible long-term effects of fault/error code P0117 include:

 

Engine Damage: Incorrect engine temperature readings can cause it to overheat or run too cold, which can cause serious engine damage over time. Overheating can warp cylinder heads, damage pistons and lead to costly repairs or engine replacement.



Reduced Fuel Efficiency: A faulty ECT sensor can affect the air-fuel mixture, causing poor combustion and reduced fuel efficiency. This can lead to increased fuel consumption and higher fuel costs over time.


Poor Engine Performance: The engine may experience rough idling, stalling, or stalling due to incorrect temperature readings from the ECT sensor. This can affect the overall performance and drivability of your vehicle.


Emissions Problems: Incorrect engine temperature readings can cause emissions to increase, causing your vehicle to fail emissions tests. This can result in fines and additional repair costs to bring your vehicle into compliance with emissions standards.



Transmission Problems: Some modern vehicles use engine temperature data to adjust transmission shift points. Incorrect temperature readings can cause erratic shifting, transmission slipping, or premature transmission wear.


Catalytic Converter Damage: Over time, improper air-fuel mixture due to a faulty ECT sensor can cause unburned fuel to enter the exhaust system. This can cause overheating and damage to the catalytic converter, resulting in costly repairs.


Increased Repair Costs: Neglecting to promptly address trouble code P0117 can lead to additional damage to other engine components, resulting in higher repair costs in the long run.



Safety Concerns: Engine overheating can pose safety risks such as sudden engine failure or fire, especially if the cooling system is compromised due to a faulty ECT sensor.


To avoid these long-term effects, it is crucial to address fault code P0117 as soon as it occurs. Accurate diagnosis and timely repairs will help maintain your vehicle's performance, efficiency and safety.

Comentarios


bottom of page