Engine Coolant Temperature Sensor 2 Circuit High
What it means
P2185 means the PCM saw an abnormally high voltage (an open or high-resistance reading) on the engine coolant temperature sensor 2 circuit — as if the engine were very cold. This is a sensor-circuit fault, not an overheating condition, but the wrong reading can make the engine run rich, hurt cold starts, and confuse cooling-fan control. The usual causes are the sensor itself or a corroded/open connector or wire.
Can I keep driving? Generally safe to drive — the car may run rich or cold-start harder and cooling fans may misbehave; fix it to protect fuel economy and emissions.
Common symptoms
What you'll notice
- Check-engine light on
- Harder cold starts or rich running (engine thinks it's cold)
- Reduced fuel economy
- Cooling fans may run constantly or not as expected
Common causes
Most likely first
- Fault in the ECT sensor 2 circuit — high resistance or open reading as maximum voltageLikely
- Faulty engine coolant temperature sensor 2Common
- Sensor harness open or shortedCommon
- Poor connection or corrosion at the sensor connectorLess often
How to diagnose & fix
Work through it in order
- Read freeze-frame data and compare sensor 2's reading to sensor 1 and actual engine temp.
- Inspect the ECT sensor 2 connector for corrosion or a loose/open terminal.
- Check for a steady ~5 V reference and a good ground, key on/engine off.
- Test the sensor's resistance against its temperature spec; an open circuit reads as high voltage.
- Replace the coolant temperature sensor 2 if it's out of spec, then re-test.
FAQ
Quick answers
Is it safe to drive with P2185?+
Can I just clear P2185?+
Related codes
Often seen with P2185
Read & clear P2185 yourself
Scan your car, confirm the code, and clear it once it's fixed — with OBD DashX on your phone.