Cause
Failed air conditioning clutch relay
The relay engaging the compressor's electromagnetic clutch, failed so the compressor cannot be driven. The module commands the relay and monitors the circuit, so it reports a control circuit fault while the compressor and the refrigerant system are untouched.
It fails in both directions and they present very differently. Failing open, the compressor never engages and there is no cooling — the ordinary complaint. Welded closed, the clutch stays engaged whenever there is power, so the compressor runs continuously including when the system should be off, which can freeze the evaporator or damage the compressor if pressures are wrong.
Relays are among the easiest components to test by substitution, since fuse boxes usually carry several identical ones. Swapping with a non-critical relay is a free and definitive check. Ask what killed it if it has welded: a clutch coil drawing above its rating, from a shorted winding or a failing bearing loading it, welds the replacement too — so measure the coil's resistance before fitting a new relay.
Typically an easy fix. Often worth checking before paying anyone to look.
Codes this can cause (3)
Codes where this is a likely explanation first, rather than merely a possible one.
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