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P0116 Code – What Does It Mean & How To Fix It

This is one of the most frequent OBD2 trouble codes. Read the full article below to know what it means, how to fix it, and what other codes may show related to it.


P0116 is an OBD-II Code that refers to Engine Coolant Temperature Circuit Range/Performance Problem


A P0116 code is caused by an ECM (Engine Control Module) receiving a signal that the engine’s coolant temperature is too high or too low. The ECM uses this as a measurement to control the coolant temperature by controlling the water pump and thermostat operation based on readings from a Coolant Temperature Sensor. However, when the sensor is out of range, the ECM gets an incorrect reading, it will store a code causing the check engine light to turn on.


Common causes for this code include:

  • Bad engine coolant temperature sensor
  • Short in coolant temperature circuit 
  • Low or dirty engine coolant
  • Broken harness or loose connectors


The symptoms of a P0116 code are:

  • MIL (Malfunction Indicator Lamp) illumination
  • The car has a lot of problems with drivability.
  • Tailpipe smoke is black.
  • Inefficient fuel efficiency
  • It’s also possible that your car won’t idle.
  • In some cases, it’s possible that the engine may stall or misfire.


To diagnose a P0116 DTC code, a technician would:

  1. Scan for codes in the ECM and look at the freeze frame data for failure.
  2. Test the engine coolant temperature circuit for continuity.
  3. Inspect leaks
  4. Locate and inspect all wiring harnesses for loose or broken connectors or bad splices.
  5. Replace any malfunctioning parts such as sensors, relay, control module, etc..

Common mistakes

The following are some of the most common mistakes that a technician may make when diagnosing a P0116 code:

  • Not verifying that all engine wiring harnesses are properly connected.
  • Not properly identifying the cause of the problem when using Freeze Frame Data.
  • Assuming that a part is good without actually testing it out.
  • Replacing parts without knowing what they do or how they work together.
  • Improperly reading and interpreting Sensor tests.

How serious is this?

A P0116 code is deemed serious since it causes the engine control module to go into a failsafe mode. The failsafe mode might cause the engine to run erratically and hesitate before getting warm, causing the engine to operate erratically and slowly.

What repairs can fix the code?

The following are solutions that may fix this problem:

  • Replacing the Coolant Temperature Sensor
  • Replacing the Coolant Temperature Limiter
  • Replacing the harness or connectors
  • Testing and replacing a control module 
  • Visually inspecting for dirty or loose components

Related codes

A P0116 is related to and may be accompanied by the following codes: 

P0115 – Engine Coolant Temperature Sensor Circuit Low Input

P0117 – Engine Coolant Temperature Sensor Circuit High Input

P0118 – Engine Coolant Temperature Circuit Intermittent

P0119 – Manifold Absolute Pressure/Barometric Pressure Circuit Range/Performance Problem

P0125 – Coolant Thermostat (Coolant Temperature Below Thermostat Regulating Temperature)


In conclusion, the P0116 code is a generic trouble code that means the computer has detected an issue with the Engine Coolant Temperature Circuit Range/Performance Problem and will cause the MIL (Malfunction Indicator Lamp) to turn on. The code is usually a result of a faulty Coolant Temperature Sensor or a loose or broken component in the circuit – both of which need replacement to fix this issue. In most cases, if left unchecked, the problem may lead to serious engine damage so stopping by for service as soon as possible is recommended.