OBD-II code · Powertrain (generic, extended)
P2184 Engine Coolant Temperature Sensor 2 Circuit Low
ECT sensor 2 reads below lower plausibility — short to ground. The engine coolant temperature sensor feeds warm-up enrichment, fan control and closed-loop entry — a stuck-cold reading keeps the engine in open loop and rich forever.
Is it safe to drive with P2184?
Usually safe to drive in the short term. Get it diagnosed when convenient, sooner if the car drives differently.
Common causes
- Most likelyShort to ground
- Less likelyConnector pins corroded - high contact resistance
- Less likelyHarness chafing through insulation
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
- Medium
- DIY friendly
- Often, with basic tools
- Typical labour
- 0.3–2 h
- Emissions test
- Likely to fail
- Parts involved
- Engine Coolant Temperature Sensor 2
Related codes
- P01E5Engine Coolant Temperature Sensor 3 Circuit Low
- P2182Engine Coolant Temperature Sensor 2 Circuit
- P2186Engine Coolant Temperature Sensor 2 Circuit Low
- P2AFEEngine Coolant Temperature Sensor 4 Circuit Low
- P2B2DEngine Coolant Temperature Sensor 5 Circuit Low
- P2BB8Engine Coolant Temperature Sensor 6 Circuit Low
- P2181Cooling System Performance
- P2183Engine Coolant Temperature Sensor 2 Circuit Range/Performance
- P2185Engine Coolant Temperature Sensor 2 Circuit High
- P2187System Too Lean at Idle (Bank 1)
Code data: OBDex open dataset (CC0). Labour times are typical ranges, not a quote.