Skip the auto shop - Our mechanics make house calls

P0115 OBD-II Trouble Code: ECT Sensor Circuit Malfunction Problem

check engine logo

P0115 code definition

Engine Coolant Temperature (ECT) sensor circuit malfunction problem

What the P0115 code means

P0115 is the OBD-II generic code that indicates when the engine control module (ECM) reads the ECT sensor input go below or above the sensors expected range of 0.14 to 4.91 V (-40°C to 140°C -40°F to 284°F).

What causes the P0115 code?

The ECT sensor range input to the ECM went to -40°F or above 284°F indicating a short or open circuit.

Codes P0117 or P0118 for a short or open circuit usually accompany code P0115.

What are the symptoms of the P0115 code?

  • The ECM turns on the Check Engine Light and goes into failsafe mode substituting input to 176 degrees F.

  • Engine may have a hard start when engine is cold and start normal when warm

  • Engine may run rough and hesitate until the engine warms up

  • Engine should run close to normal once the engine warms up

Note: The symptoms are determined by the manufacturer failsafe ECM strategy for the vehicle during a failure and may vary between manufacturers and vehicles.

How does a mechanic diagnose the P0115 code?

  • Scans and documents the codes received and view the freeze frame data to see when the code was set

  • Resets the codes to clear the OBD-II fault codes and retests the vehicle to see if the code comes back

If Codes P0117 or P0118 are received, the mechanic follows tests for these codes first.

Common mistakes when diagnosing the P0115 code

  • Not performing a visual inspection first

  • Not performing tests on codes P0117 or P0118 first

  • Not replacing ECT sensor unless tests indicate a problem

  • Not connecting the new ECT sensor and viewing the ECM data to see if the temperature output from the sensor is close to the same as ambient temperature before installation

How serious is the P0115 code?

  • The P0115 code will cause the engine ECM to go into a failsafe mode.

  • The failsafe mode may cause various drive complaints until the engine warms up depending on the manufacturer failsafe mode strategy.

What repairs can fix the P0115 code?

  • Repairing or replacing the ECT connector
  • Repairing or replacing the wiring as necessary
  • Replacing the ECT with a new sensor

Additional comments for consideration regarding the P0115 code

  • The P0115 code is often associated with P0116, P0117, P0118, and P0119 codes.

  • Most failures for code P0115 is a harness shorting or a connector corrosion issue causing an open circuit.

Need help with a P0115 code?

YourMechanic offers certified mobile mechanics who will come to your home or office to diagnose and repair your vehicle. Get a quote and book an appointment online or speak to a service advisor at 1-800-701-6230.

The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details

Skip the repair shop, our top-rated mechanics come to you.

At your home or office

Choose from 600+ repair, maintenance & diagnostic services. Our top-rated mechanics bring all parts & tools to your location.

Fair & transparent pricing

See labor & parts costs upfront, so you can book with confidence.

12-month, 12,000-mile warranty

Our services are backed by a 12-month, 12,000-mile warranty for your peace of mind.

Get A Quote

Ask a Mechanic
(100% Free)

Have a car question? Get free advice from our top-rated mechanics.

Ask A Mechanic
Over 10,000 questions answered!

Need Help With Your Car?

Our certified mobile mechanics make house calls in over 2,000 U.S. cities. Fast, free online quotes for your car repair.


Post a question and get free advice from our certified mechanics.


More related articles

How Long Does a Fuel Filler Neck Last?
Getting gas from the pump to your gas tank is the only way to keep a car going. The fuel filler neck is a metal tube that is welded to the...
P0121 OBD-II Trouble Code: TPS "A" Circuit Range Performance Problem
P0121 code definition Throttle Pedal Position Sensor/Switch (TPS) A Circuit Range Performance Problem What the P0121 code means P0121 is a generic OBD-II code which indicates that the Engine Control...
P0240 OBD-II Trouble Code: Turbocharger Boost Sensor B Circuit Range/Performance
P0240 code definition Turbocharger Boost Sensor B Circuit Range/Performance What the P0240 code means P0240 is an OBD-II generic code triggered when the Engine Control Module (ECM) detects the intake boost...

Related questions

Q: Car says energy power reduced then engine light came on

The first thing to do would be to have the Check Engine Light trouble code pulled from the car for a place to start. Common problems are things like a faulted throttle body motor or throttle body position sensor which...

Q: Stalls out when I put in drive p1729

Given your mileage, it is likely the throttle body and idle air controller need cleaning. It is also possible the throttle position sensor (which communicates with the transmission) may also be failing. This would seem more likely since your replacement...

Q: Check Engine code is P0115

Hi. The most common repair for that code is the sensor itself. A low coolant condition can cause it as well so the cooling system will need to be inspected. It will need to be checked for leaks and the...