Cause
Overcharged refrigerant system
Too much refrigerant in the air conditioning system, which raises pressure and reduces cooling rather than improving it. More refrigerant does not mean more cooling — the system depends on the refrigerant changing state at particular pressures, and an overcharge floods the condenser so less of it can condense.
The result is high-side pressure above its expected range, which the module reads and acts on: it will cut the compressor to protect the system, so the complaint is air conditioning that works briefly and then stops, repeatedly. Cooling that is poor and gets worse as the system runs is the pattern, and it is the opposite of the undercharge people assume.
Top-up cans are the usual route in, since they let refrigerant be added with no way to measure the total charge. The only correct method is to recover the charge, weigh it, and refill to the specified mass — which is also the only way to find out whether the system was overcharged or has some other restriction. Non-condensable air in the system produces the same high pressures, and it arrives the same way, so evacuation matters as much as the charge weight.
Typically a moderate job.
Codes this can cause (3)
Codes where this is a likely explanation first, rather than merely a possible one.
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