P2186Engine Coolant Temperature Sensor 2 Circuit Intermittent/Erratic
- Generic OBD-II code · Powertrain
- Turns on the check-engine light
- Matters for the ITP
- How the car detects it
- P2186 covers a sensor 2 signal that jumps instead of changing smoothly. Coolant temperature moves slowly because of the mass of the liquid, so a step faster than physics allows points to a loose contact rather than a real change. GM's 2019 tables (19OBDG03D) work out an upper and lower limit for each new reading from the previous value and the sensor's time constant, about 7.4 s for sensor 2 within a -60 to 150 °C window; a reading outside this corridor for 5 s within 6 s sets the code as Type B, MIL after two trips. GM also lists P2186 among the effects of the chafed engine harness in bulletin 21-NA-149. Typical causes are worn connector pins, a wire broken inside the insulation or a sensor with an intermittent element. Steady low or high signals are P2184 and P2185.
- What you may notice
- Check engine light after two drives
- Fans switching on and off irregularly
- Temperature-related messages that appear and vanish
- Likely causes
- LikelyWorn or loose pins in the sensor 2 connector
- PossibleWire broken inside its insulation or chafed harness making intermittent contact
- RareSensor 2 with an intermittent internal fault
- Inspection (ITP)
- Matters for the ITP. While the check-engine light is on, the car fails the emissions check.
- Repair
- Easy · Often possible to do yourself.Typical cost: €30 – €250
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.