P0117 Fault Code

Engine Coolant Temperature Circuit Low Input

• What does that mean?
• Symptoms
• Causes
• Solutions

The P0117 fault code indicates a problem with the Engine Coolant Temperature (ECT) sensor circuit, specifically an input that is lower than expected by the engine control unit (ECU). This could signify that the engine is running cooler than it should, or there is a malfunction within the sensor circuit itself.

What are the symptoms of the P0117 code?

Symptoms associated with a P0117 fault code may include:

• Poor fuel economy due to incorrect air-fuel mixture adjustments
• Engine running overly rich or lean
• Check Engine Light illuminated on the dashboard
• Difficulty starting the engine or fluctuating engine temperature readings

What causes the P0117 code?

Common causes for the P0117 code include:

• A malfunctioning engine coolant temperature sensor
• Damaged wiring or connectors in the ECT sensor circuit
• A short circuit or an open circuit in the ECT sensor wiring
• Engine coolant leaks leading to incorrect sensor readings

How to fix P0117?

To resolve the P0117 code, you may consider the following steps:

• Inspect and test the engine coolant temperature sensor for proper function based on manufacturer specifications.
• Check the wiring and connectors for signs of damage, corrosion, or loose connections.
• Replace the coolant temperature sensor if it's found to be defective.
• Clear the fault code from the ECU after repairs and conduct a test drive to ensure the issue is resolved.