P0118 OBD-II Trouble Code: Engine Coolant Temperature (ECT) Sensor Circuit High Open Problem

Our certified mechanics come to you · Get a fair and transparent estimate upfront

Red-stars EXCELLENT RATING ON

Cost of diagnosing the P0118 code

P0118 is a diagnostic trouble code (DTC) for "Engine Coolant Temperature (ECT) Sensor Circuit High Open Problem". This can happen for multiple reasons and a mechanic needs to diagnose the specific cause for this code to be triggered in your situation. Our certified mobile mechanics can come to your home or office to perform the Check Engine Light diagnostic for $114.99 . Once we are able to diagnose the problem, you will be provided with an upfront quote for the recommended fix and receive $20.0 off as a credit towards the repair. All our repairs are backed by our 12-month / 12,000-mile warranty.

Cars Estimate Credit towards follow-up repair Earliest Availability
Ford $114.99 $20.0
Toyota $114.99 $20.0
BMW $124.99 $20.0
SCHEDULE P0118 DIAGNOSTIC Get a fair and transparent estimate upfront

P0118 code definition

Engine Coolant Temperature (ECT) sensor circuit high open problem

What the P0118 code means

P0118 is the OBD-II generic code that indicates the Engine Control Module (ECM) has seen the ECT sensor output go more than 4.91 V or less than -40°C (-40°F).

What causes the P0118 code?

The ECT sensor range input to the ECM went to 4.91 or less than -40 deg F indicating an open circuit in the sensor, connector or wiring.

What are the symptoms of the P0118 code?

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

  • The engine may have a hard start when engine is cold, and start normal when warm.

  • The engine may run rough and hesitate until the engine warms up.

  • The 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 P0118 code?

  • Inspects for disconnected sensor connectors or damaged connectors

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

  • Clears the OBD-II fault codes and retests the system to see if the code comes back

  • Disconnects the sensor connector and inspects for corrosion or bent pins and repairs as needed.

  • Connects the two connector pins together to see if the output on scanner shows above 284 deg F, indicating the wiring is okay, and replaces the ECT sensor

  • Above 284 deg F, the circuit has an open circuit in the wiring, connector or ECM and will be fixed by the technician

Common mistakes when diagnosing the P0118 code

  • Not visually inspecting the problem area first

  • Not following the manufacturer's pinpoint test procedure step-by-step, and skipping steps

  • Replacing the ECT sensor without knowing for sure that it is the problem

  • Not connecting it and viewing the ECM data to see if the temperature output from the sensor is as expected before installation of the new ECT sensor

How serious is the P0118 code?

The P0118 code will put the engine ECM to go into a failsafe mode, which may cause the engine to run rough, or hesitate until the engine warms up to operating temperature. The failsafe mode may also cause excessive fuel consumption, carbon fouling of engine components, and various drive complaints, depending on the manufacturer's failsafe mode strategy. Driving a vehicle for an extended time with the vehicle in failsafe mode may require additional repairs to remove carbon, or repair possible ignition problems. Also, electrical cooling fans may run continuously while the engine is running.

What repairs can fix the P0118 code?

Additional comments for consideration regarding the P0118 code

Most failures for code P0118 involve ECT sensor open circuit failure.

Need help with a P0118 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.

Check Engine Light
P0118
trouble codes

No more waiting rooms! Our mechanics will come to you to diagnose and fix the P0118 code.

SCHEDULE P0118 DIAGNOSTIC
Get a $20 credit for the follow-up repair

Recent Check Engine Light is on Inspection reviews

Excellent Rating

(7400)

Rating Summary
6879
249
58
41
173
6879
249
58
41
173
 at YourMechanic

David

13 years of experience
393 reviews
David
13 years of experience
Chevrolet Malibu L4-2.4L - Check Engine Light is on Inspection - Marietta, Georgia
He explained everything to me in detail on what I needed to know about my car. Definitely recommend him for getting the job done.
 at YourMechanic

Raymond

37 years of experience
402 reviews
Raymond
37 years of experience
Toyota Camry L4-2.2L - Check Engine Light is on - Las Vegas, Nevada
Raymond did a great job however I was charged for two hours labor and he was only here less than 45 minutes. should I expect this on future appointments with your mechanic ?
 at YourMechanic

Shane

17 years of experience
217 reviews
Shane
17 years of experience
Volkswagen EuroVan V6-2.8L - Check Engine Light is on Inspection - Austin, Texas
Arrived on time. Explained the issues he found and how he will fix it. I have parts on order and will schedule an appointment to have Shane install the parts when they arrive.
 at YourMechanic

Kanstantsin

19 years of experience
51 reviews
Kanstantsin
19 years of experience
Ford F-150 V8-4.6L - Check Engine Light is on Inspection - Littleton, Colorado
Kanstantsin arrived early. Was very courteous and professional. Will highly recommend to anyone. Thank you Kanstantsin.


Related questions

I have a Code P0601 on the PCM. I replaced the PCM, and now I have a code P0118, code P0123, and code P0193.
Hi there, the short answer to your question is no . A PCM with a P0601 (https://www.yourmechanic.com/article/-p0601-obd-ii-trouble-code-internal-control-module-memory-check-sum-error-by-spencer-clayton) (which is a memory module error in the PCM) cannot reliably retrieve codes for the codes you list (P0118 (https://www.yourmechanic.com/article/p0118-obd-ii-trouble-code-engine-coolant-temperature-ect-sensor-circuit-high-open-problem-by-jay-safford) - coolant temp...

More related articles

P0250 OBD-II Trouble Code: Turbocharger Wastegate Solenoid B Circuit High
P0250 P0250 code definition Turbocharger Wastegate Solenoid B Circuit High What the P0250 code means P0250 is an OBD-II generic code that the engine control module (ECM) detected the Turbocharger Wastegate Solenoid B input circuit high above specifications indicating a...
P0804 OBD-II Trouble Code: Upshift (Skip Shift) Lamp Control Circuit Malfunction
What What the P0804 code means Your vehicle’s powertrain control module (PCM) has detected a malfunction in the one through four skip shift solenoid lamp control circuit. The one through four skip shift solenoid control circuit is also known as...
P0595 OBD-II Trouble Code: Cruise Control Servo Control Circuit Low
P0595 means an issue with the cruise control servo control circuit which causes the cruise control on the vehicle to work poorly or not at all.

How can we help?

Our service team is available 7 days a week, Monday - Friday from 6 AM to 5 PM PST, Saturday - Sunday 7 AM - 4 PM PST.

1 (855) 347-2779 · hi@yourmechanic.com