2010 Mazda B Series OBD2 Code P2181 Cooling System Performance

What Does P2181 Code Mean?

OBD-II Code P2181 is defined as a Cooling System Performance

The engine computer (PCM) monitors coolant temperature in the radiator (Radiator Coolant Temperature Sensor) and in the engine (Engine Coolant Temperature Sensor). On cold startup, the PCM will compare these to readings to verify proper operation of thermostat. If the temperature difference is not within specifications, code P2181 will set.

P2181 Symptoms

• A/C may not operate
• Cooling fans may stay on all the time
• Heater will not work

Common Problems That Trigger the P2181 Code

• Engine coolant heater failure
• Engine coolant level is too low
• Thermostat failure

Common Repairs Needed for the P2181 Code

• Engine Coolant Temperature Sensor Replacement
• Thermostat Replacement