P2184
Engine Coolant Temperature Sensor 2 Circuit Low
Engine cooling / sensors
Generic OBD-II
Low
What it means
P2184 means the ECM sees an abnormally low voltage from the second engine coolant temperature sensor, usually from a wiring short to ground or a failed sensor. It's a signal fault rather than a real overheating event, so the car still drives, but the ECM may lean on a default value that nudges fan and fueling behavior until it's corrected.
Low
Can I keep driving? Safe to drive — it's a sensor-signal fault. The engine runs, though cooling-fan or fueling behavior may be slightly off until it's fixed.
Common symptoms
What you'll notice
- Check-engine light on
- Inaccurate coolant temperature reading
- Cooling fans running more than usual or fueling slightly off
- Often no obvious change in how the car drives
Common causes
Most likely first
- Signal wire shorted to ground (drives the voltage low)Likely
- Faulty engine coolant temperature sensor 2Common
- Poor connection or corrosion at the sensor connectorCommon
- Chafed or damaged sensor harnessLess often
- Rarely, a faulty ECM/PCMLess often
How to diagnose & fix
Work through it in order
- Read freeze-frame data and check the sensor 2 temperature reading for an implausible value.
- Inspect the connector and harness for a short to ground, corrosion, or damage.
- Backprobe the sensor (key on, engine off) for the expected reference voltage and a clean ground.
- Compare sensor 2 resistance against spec at a known temperature.
- If the wiring is good but the sensor is out of range, replace it and retest.
FAQ
Quick answers
Is it safe to drive with P2184?+
Yes. This is a temperature-sensor circuit fault, not an actual overheating condition, though it's worth confirming coolant level and fan operation.
Can I just clear P2184?+
It comes back until the shorted circuit or failed sensor is repaired.
Related codes
Often seen with P2184
Read & clear P2184 yourself
Scan your car, confirm the code, and clear it once it's fixed — with OBD DashX on your phone.
✓ Verified name — SAE J2012 / ISO 15031-6Guidance reviewed by OBD DashX