P0116
Fix within 1-2 weeksThe engine computer detects an inconsistent or illogical reading from the Engine Coolant Temperature (ECT) sensor, meaning the temperature doesn't match expected values for engine operation.
Code P0116 means your engine computer sees an inconsistent engine coolant temperature. Common causes: Faulty ECT sensor (60%), wiring issues (20%), stuck thermostat (15%). Drivability: Yes, fix within 1-2 weeks. Repair cost: $20-$140 DIY, $100-$500 professional.
Can I Drive With P0116?
Yes, safe to drive
No restrictions, but fix within 1-2 weeks to prevent further issues and maintain fuel economy.
Stop driving immediately if: Engine temperature gauge shows overheating, steam from under the hood, significant power loss, or a flashing Check Engine Light.
Symptoms of P0116
- 1Check Engine Light is on
- 2Engine runs rough or idles poorly
- 3Poor fuel economy
- 4Hard starting, especially when cold
- 5Engine overheating (if sensor reads too low)
- 6Engine running cold (if sensor reads too high)
- 7Black smoke from exhaust
Common Causes of P0116
Parts most likely causing this code, ranked by probability
The sensor itself has failed and is sending incorrect temperature data to the engine computer.
60% of P0116 cases are fixed by replacing the ECT sensor
Damaged wires, corroded pins, or a loose connection can disrupt the signal from the sensor.
20% of P0116 cases are fixed by repairing the wiring or connector
A thermostat stuck open or closed prevents the engine from reaching or maintaining the correct operating temperature, causing the ECT sensor reading to be out of range.
15% of P0116 cases are fixed by replacing the thermostat
Insufficient coolant can cause the sensor to read air pockets or incorrect temperatures, leading to an illogical reading.
5% of P0116 cases are fixed by topping off coolant and checking for leaks
Check These First (Before Buying Parts)
- Check your engine's coolant level. Ensure it's full and clean.
- Visually inspect the wiring harness and electrical connector for the ECT sensor for any signs of damage, fraying, or corrosion.
How to Diagnose P0116
- 1Check engine coolant level and condition. Top off if low.
- 2Visually inspect the ECT sensor and its electrical connector for damage, corrosion, or loose connections.
- 3Using a multimeter, test the resistance of the ECT sensor at various temperatures (if accessible and safe to do so). Compare readings to manufacturer specifications.
- 4Use an OBD-II scan tool to monitor live data for the ECT sensor. Compare its reading to ambient air temperature when the engine is cold, and observe its rise as the engine warms up.
- 5Feel the upper and lower radiator hoses as the engine warms up to check for proper thermostat operation (upper hose should get hot first, then lower hose once thermostat opens).
- 6If all other components check out, consider a faulty engine control module (ECM/PCM), though this is rare.
P0116 on Popular Vehicles
Honda Accord
2003-2024P0116 on Honda Accords is commonly linked to a faulty ECT sensor, often resulting in poor fuel economy or erratic temperature gauge readings. The sensor is usually located near the thermostat housing.
65% fixed by replacing the ECT sensor
Toyota Camry
2007-2024Toyota Camrys frequently experience P0116 due to a failing ECT sensor. This can lead to issues with cold starts and the engine running rich or lean. Inspecting the sensor and its wiring is crucial.
60% fixed by replacing the ECT sensor
Ford F-150
2004-2024On Ford F-150 trucks, P0116 can sometimes be traced to wiring harness issues or corrosion at the ECT sensor connector due to exposure to harsh conditions. Always check the wiring thoroughly before replacing the sensor.
50% fixed by replacing the ECT sensor, 25% by repairing wiring
Frequently Asked Questions
What does P0116 mean?
P0116 indicates that your vehicle's engine computer has detected an issue with the Engine Coolant Temperature (ECT) sensor circuit, specifically that the temperature reading is out of expected range or inconsistent with other engine data.
Can I drive with P0116?
Yes, you can drive with P0116, but fix it within 1-2 weeks. Ignoring this code can lead to poor fuel economy, increased emissions, and in some cases, engine overheating or running too cold, which can cause long-term engine damage.
Will P0116 clear itself?
No, P0116 will not clear itself. The engine computer will continue to detect the inconsistency in the ECT sensor circuit. You will need to diagnose and repair the underlying issue, then clear the code with an OBD-II scan tool.
How do I fix P0116 myself?
Start by checking your coolant level and inspecting the ECT sensor wiring for damage. If those are good, you can test the ECT sensor with a multimeter or replace it. If the sensor is good, consider replacing the thermostat.
How much does it cost to fix P0116?
DIY repair costs for P0116 range from $20-$140, primarily for a new ECT sensor or thermostat. Professional repair at a shop typically costs $100-$500, including parts and labor.
P0116 keeps coming back - why?
P0116 keeps coming back because the root cause was not fully addressed. This often happens if you only replaced the ECT sensor but the actual problem was a faulty thermostat, wiring issue, or low coolant. A thorough diagnosis is essential.
Will P0116 fail emissions/smog test?
Yes, P0116 will cause your vehicle to fail an emissions or smog test. The Check Engine Light being on automatically results in a failure, and an inaccurate coolant temperature reading directly impacts emission control systems.
What's the difference between P0116 and P0115?
P0115 indicates a general malfunction in the ECT sensor circuit, meaning the computer isn't getting any signal or a completely out-of-range signal. P0116 specifically means the signal is inconsistent or illogical, suggesting a range or performance issue rather than a complete circuit failure.
P0116 on Honda Civic?
On Honda Civics, P0116 is frequently caused by a failing Engine Coolant Temperature (ECT) sensor. These sensors can degrade over time, sending erratic signals to the ECU, leading to poor fuel economy or rough idling. Checking the sensor and its connector is a good first step.
Questions to Ask Your Mechanic
Did you check the live data from the ECT sensor and compare it to the intake air temperature sensor when the engine was cold?
Good answer: Yes, the ECT sensor read X degrees, and the IAT sensor read Y degrees. They were within a few degrees of each other, indicating the sensor itself is likely accurate at ambient temperature.
What was the resistance reading of the ECT sensor at operating temperature, and how does it compare to factory specifications?
Good answer: At operating temperature, the sensor read X ohms, which is within the specified range of Y-Z ohms for this vehicle.
Did you verify the thermostat is opening and closing correctly?
Good answer: Yes, I monitored the engine temperature and felt the radiator hoses. The thermostat opened at the correct temperature, allowing coolant to flow through the radiator.
Repair Cost Estimate
DIY Repair
Parts only
$20-$140
Shop Repair
Parts + labor
$100-$500
Save $80-$360 by doing it yourself
Difficulty
intermediate
Time
1-3 hours
Intermediate - while replacing the sensor can be simple, accurately diagnosing whether the sensor, wiring, or thermostat is the root cause requires a multimeter and an OBD-II scan tool.
Cost of Waiting
Ignoring P0116 can lead to significantly reduced fuel economy and increased emissions. If the engine runs too hot or too cold for extended periods, it can cause premature wear on internal engine components, potentially leading to costly repairs like head gasket failure or catalytic converter damage ($800-$2,500 repair). A $50 sensor fix now prevents a $1,000+ bill later.
While You're In There...
If you're draining coolant to access the ECT sensor, or if the thermostat is suspected as a cause, it makes sense to replace it at the same time to avoid repeat labor.
If you drain coolant to replace the sensor or thermostat, it's a good opportunity to flush and refill with fresh, manufacturer-specified coolant.
Tools You'll Need
- OBD-II Scan Tool
- Multimeter
- Wrench Set
- Pliers
- Coolant Drain Pan
- Funnel
- ECT Sensor Socket (if applicable)
P0116 is a common code that points to an issue with your engine's temperature monitoring. Most repairs are straightforward, often involving a sensor or thermostat replacement, and your engine will run more efficiently afterward.
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Your Next Steps
Step 1: Check your engine's coolant level and visually inspect the ECT sensor's wiring and connector for any obvious damage or corrosion.
Step 2: If the visual inspection doesn't reveal the problem, use an OBD-II scan tool to monitor the live data from the ECT sensor. Compare its reading to the ambient air temperature when the engine is cold. If the readings are significantly different, the sensor is likely faulty.
Step 3: If the sensor appears to be reading correctly, or if replacing it doesn't fix the issue, consider testing or replacing the thermostat. Parts you'll likely need: new ECT sensor, possibly a new thermostat, and fresh engine coolant.