P2184Engine Coolant Temperature Sensor 2 Circuit Low
- Generic OBD-II code · Powertrain
- Turns on the check-engine light
- Matters for the ITP
- How the car detects it
- Coolant sensors are NTC thermistors: the hotter they get, the lower their resistance and voltage. P2184 therefore reports a signal from sensor 2 so low that it would mean an impossibly hot engine, typically a signal wire touching ground or a shorted sensor. GM's 2019 tables (19OBDG03D) set it when resistance drops below about 47.5 ohms, matching 150 °C, for 5 s within 6 s (Type B, MIL after two trips). VW's 2014 CC flags the radiator outlet sensor above 141 °C, the Touareg CNRB a voltage under 0.22 V. GM lists P2184 among the codes caused by a chafed engine harness in bulletin 21-NA-149. Because a hot reading is accepted as real at first, fans may run flat out. P2185 is the opposite fault, P2186 the erratic case.
- What you may notice
- Check engine light after two drives on GM vehicles
- Radiator fans running at full speed
- Further codes and warnings if a harness is chafed
- Likely causes
- LikelySignal wire of sensor 2 chafed through and touching ground
- PossibleSensor 2 internally shorted
- RareCoolant or water in the connector bridging signal and ground
- 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.