P2181 - Cooling System Performance

The Technical Definition: The PCM determines that the cooling system is not operating within the expected temperature range, indicating a mechanical failure rather than a purely electrical sensor failure.

Common Symptoms: The temperature gauge may fluctuate wildly, the engine may overheat, or it may take entirely too long to warm up.

Typical Fix: This is an umbrella code for the cooling system. On the JK, you should immediately inspect the water pump for "weeping" (a small coolant leak from the bottom of the pulley). If the water pump is dry, the thermostat is the next most likely culprit.