Powertrain, generic (extended)

P2184 Engine Coolant Temperature Sensor 2 Circuit Low

Check engine lightOn
EmissionsRelevant
Drive cycleNot required
Limp modeNo

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.

Likely causes

Signal wire of sensor 2 chafed through and touching ground
Sensor 2 internally shorted
Coolant or water in the connector bridging signal and ground

Symptoms

  • Check engine light after two drives on GM vehicles
  • Radiator fans running at full speed
  • Further codes and warnings if a harness is chafed

Repair estimate

DifficultyEasyDIY possible
Parts and labour€30–250
Time0.3–2 h

Typical range across vehicles; the real cost depends on what the testing finds.

Parts involved

engine coolant temperature sensor 2

Related codes

P2185P2186P2182P2183P0117P01E5

References: gsi.ext.gm.com, static.nhtsa.gov, static.nhtsa.gov, static.nhtsa.gov.