6 days ago
P0117: Engine Coolant Temperature Sensor Circuit Low Input
What does the P0117 error code mean?
The check engine P0117 diagnostic trouble code stands for "Engine Coolant Temperature (ECT) Sensor Circuit Low Input." This diagnostic trouble code is triggered when your vehicle's powertrain control module detects low voltage input outside the normal range from the first engine coolant temperature sensor, indicating your engine is running either too hot or too cold.
Why is this issue important?
Your engine carefully regulates its temperature, using engine coolant and oil to maintain an optimal operating temperature. Coolant absorbs heat from the engine and dissipates it through the radiator. With temperatures running too hot, your engine could damage certain critical components. When the thermometer swings too far the other way and things run too cool, your engine could burn excess fuel, leading to poor gas mileage and efficiency.
Can I safely drive my car with this error code?
It's best not to drive with a P0117 code. A malfunctioning engine coolant temperature sensor or fault detected by the powertrain control module can cause any of the above issues, including engine damage or excessive fuel consumption. Many modern engines contain software that will put the engine into a 'limp mode,' restricting performance to preserve internal components and prevent further damage.
Common symptoms of the P0117 error code
The check engine light is illuminated
Poor fuel economy
The engine may run rich (too much fuel) or lean (too little)
Difficulty starting the engine, especially in colder temperatures
Overheating and high temperature gauge readings
The engine cooling fans are running constantly
How is the P0117 error code diagnosed?
Use an OBD-II scanner : Check for the consistent presence of the P0117 code and any other related errors.
: Check for the consistent presence of the P0117 code and any other related errors. Inspect the engine coolant temperature sensor and wiring : Inspect the sensor and its connections for damage, rust or fraying.
: Inspect the sensor and its connections for damage, rust or fraying. Measure sensor voltage : A multimeter tool can detect voltage issues within the sensor circuit or faults within the sensor's function itself.
: A multimeter tool can detect voltage issues within the sensor circuit or faults within the sensor's function itself. Check coolant levels and condition: Low coolant can cause high engine temps, triggering the code. Check coolant levels and ensure your coolant is not old or rusty.
How is the P0117 error code repaired?
Replace the faulty engine coolant temperature sensor.
Repair or replace damaged wiring in the engine coolant temperature sensor circuit.
Replace or refill engine coolant if the quality or quantity is below optimal ranges.
Clear the error code and perform a test drive to confirm the issue was resolved by one of the above remedies.
More information on OBD-II diagnostic trouble codes
Follow the link below to reach our diagnostic check engine trouble codes catalog:
On-board diagnostics (OBD-II) trouble code directory
