OBD-II code · Powertrain (generic, extended)
P2186 Engine Coolant Temperature Sensor 2 Circuit Low
The second coolant temperature sensor reports a voltage below the lower threshold — typically a short to ground or a sensor with very low resistance.
Is it safe to drive with P2186?
Usually safe to drive in the short term. Get it diagnosed when convenient, sooner if the car drives differently.
Common causes
- Most likelySignal shorted to ground
- PossibleSensor element shorted
- Less likelyConnector pins corroded - high contact resistance
Symptoms
- Check engine light on
- Cooling fan runs constantly or not at all
- Cabin heater weak or excessively hot
- Possible long warm-up time or hard cold start
Repair at a glance
- Difficulty
- Easy
- DIY friendly
- Often, with basic tools
- Typical labour
- 0.3–1 h
- Emissions test
- Likely to fail
- After the fix
- A drive cycle is needed before the light stays off
- Parts involved
- Coolant Temperature Sensor 2, Sensor Wiring
Related codes
- P01E5Engine Coolant Temperature Sensor 3 Circuit Low
- P2184Engine Coolant Temperature Sensor 2 Circuit Low
- P2185Engine Coolant Temperature Sensor 2 Circuit High
- P2AFEEngine Coolant Temperature Sensor 4 Circuit Low
- P2B2DEngine Coolant Temperature Sensor 5 Circuit Low
- P2BB8Engine Coolant Temperature Sensor 6 Circuit Low
- P2183Engine Coolant Temperature Sensor 2 Circuit Range/Performance
- P2187System Too Lean at Idle (Bank 1)
- P2188System Too Rich at Idle (Bank 1)
- P2189System Too Lean at Idle (Bank 2)
Code data: OBDex open dataset (CC0). Labour times are typical ranges, not a quote.