Jimm 8/26/2012The coolant sensor's impact on the engine management system, cold driveability, emissions and fuel economy can also be influenced by the thermostat. If the thermostat is stuck open, the engine will be slow to warm up and the coolant sensor will read low. Or, if someone installed the wrong thermostat for the application or removed the thermostat altogether, it will prevent the engine from reaching normal operating temperature and cause the coolant sensor to read low.
There is also the possibility of a faulty coolant sensor - the least expensive and least complicated for the first step would be to check (bypass / wire around) the coolant sensor itself. If the low coolant light goes out - then you have found the issue. Then, just replace the coolant sensor.
Try the coolant sensor and other replacement parts - from the many on-line auto parts sources, such as; www.RockAuto.com, or www.autopartswarehouse.com.