P1116
ToyotaEngine Coolant sensor out of range/ECT Sensor Out Of Self Test Range
Medium SeverityThe P1116 code indicates that the Engine Coolant Temperature (ECT) sensor is sending an implausible signal to the engine computer, or its readings are outside the expected range during self-test. This can lead to issues with fuel mixture, affecting fuel economy and potentially causing drivability problems like rough idling or poor acceleration.
⚠️ Before You Begin (Safety First)
Always allow the engine to cool completely before working on the cooling system to prevent burns. Disconnect the battery's negative terminal before performing any electrical work. Wear appropriate eye protection and gloves.
Common Symptoms
- Check Engine Light illuminated
- Poor fuel economy
- Engine running rich or lean
- Rough idle or stalling
- Engine takes longer to warm up
- Difficulty starting the engine (especially when cold)
Common Causes
- Faulty Engine Coolant Temperature (ECT) sensor
- Corroded or damaged ECT sensor electrical connector
- Open or short circuit in the ECT sensor wiring harness
- Low engine coolant level (though less common for this specific code)
- Faulty thermostat (causing incorrect temperature readings)
- Issues with the Engine Control Module (ECM) (rare)
Frequently reported on: Toyota Camry 2005-2015, Toyota Corolla 2003-2010, Toyota Tacoma 2004-2014, Toyota Highlander 2001-2013, Toyota RAV4 2006-2012
Diagnostic Steps
- Locate the Engine Coolant Temperature (ECT) sensor. It's usually found near the thermostat housing or on the cylinder head.
- Inspect the ECT sensor's electrical connector for corrosion, bent pins, or damage. Clean any corrosion with electrical contact cleaner.
- Check the wiring harness leading to the ECT sensor for any visible signs of damage, fraying, or shorts.
- With the engine cool, disconnect the ECT sensor and test its resistance using a multimeter. Compare the readings to your vehicle's service manual specifications for different temperatures.
- If the sensor tests bad or wiring is damaged, replace the faulty ECT sensor or repair the wiring.
- After replacement, clear the P1116 code using an OBD-II scanner and test drive the vehicle to ensure the code does not return.
👨🔧 When to Call a Professional
If the problem persists after replacing the ECT sensor and verifying wiring, or if other engine performance issues are present, it is best to consult a professional mechanic. There could be a more complex underlying electrical issue or a problem with the Engine Control Module (ECM).
Commonly Asked Questions
What is the Engine Coolant Temperature (ECT) sensor?
The ECT sensor monitors the engine coolant's temperature and sends this data to the Engine Control Module (ECM). This information is crucial for determining fuel injection, ignition timing, and cooling fan operation.
Can I drive with a P1116 code?
While you might be able to drive, it is not recommended for extended periods. A faulty ECT sensor can lead to poor fuel economy, increased emissions, and potentially cause the engine to run too rich or too lean, which can damage other components over time.
Is the ECT sensor the same as the coolant temperature sender for the gauge?
No, often they are separate. Many vehicles have one sensor for the ECM (ECT sensor) and a different sender unit to operate the dashboard temperature gauge. Some modern vehicles combine these functions into one sensor.
What tools do I need to replace an ECT sensor?
You will typically need a wrench or a specific sensor socket, a ratchet, a multimeter for testing, electrical contact cleaner, and possibly a pan to catch any dripping coolant.
Do I need to bleed the cooling system after replacing the ECT sensor?
It depends on how much coolant was lost. If only a small amount was lost, simply topping off the reservoir might suffice. If a significant amount drained, you may need to bleed air from the cooling system to prevent overheating and ensure proper function.