Apparatus and method

A method of determining a characteristic of a fluid in a replaceable fluid container for a vehicle comprising a fluid circulation system, wherein the method is performed by a controller, the method comprising:

• determining, using one or more temperature sensors, a temperature associated with the fluid in the replaceable fluid container;
• wherein the replaceable fluid container is coupled to a fluid path coupled to the fluid circulation system, and
• wherein at least one electrical pump is configured to be powered or driven by a battery of the vehicle and to cause fluid flow between the replaceable fluid container and the fluid circulation system through the fluid path;
• determining an electrical load associated with the electrical pump in a predetermined mode of operation;
• and
• comparing the determined electrical load with at least one expected electrical load associated with the determined temperature and the predetermined mode of operation, to provide a measure of the characteristic of the fluid.