تسرب وسيط التبريد

Refrigerant escaping from the air conditioning system, so the charge falls below what the system needs. These systems are sealed and lose nothing in normal use — a low charge always means a leak, and topping one up without finding it is a repair with a known expiry date.

Low charge means low pressure, and the module protects the compressor by refusing to run it, because the refrigerant also carries the oil that lubricates it. So the complaint is air conditioning that stops working, and running a system low on charge damages the compressor rather than merely cooling badly.

The commonest leak points are the condenser — at the front of the vehicle where stones reach it — the compressor's shaft seal, and the flexible hoses' crimped fittings. Leak detection uses dye or an electronic detector rather than inference; and recovering, weighing and recharging to the specified mass is the only way to know what the system actually holds. Refrigerant is a regulated substance and must be recovered rather than vented.