P2181 – Cooling System Performance

Meaning:

When somewhere in the engine, the temperature is out of range, the P2181 happens
The P2181 is triggered when somewhere in the engine, the temperature is out of range

A vague OBD2 code, the P2181 suggests that there’s somewhere in the engine where the temperature is out of range (either too hot or too cold).

Main Symptoms:

  • Check Engine Light comes on
  • Temperature gauge indicates too high or too low temp
  • If the temp is too cold the engine will have a rich condition

Possible Causes:

  • Defective engine coolant temperature (ECT) sensor
  • Wiring or connector problem in ECT circuit
  • Thermostat is stuck open or closed
  • Presence of air in cooling system
  • Low engine coolant level

Diagnostic Steps:

  • If the engine is running too cold replace thermostat
  • Check to ensure there are no open, broken, disconnected, shorted or burnt wires and connectors in ECT circuit
  • Check whether fan is working. If it’s wobbling or has a leak tighten or replace the fan. Remember to check its fuse as well
  • Test the resistance of ECT sensor. If it’s off the recommended reading replace the sensor

Read More: OBD2 Codes List: Meaning, Fixes, and Free Download