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The module receiving the wheel sensors' transmissions, faulty so pressures cannot be read. Direct systems use a battery-powered sensor in each wheel transmitting by radio, and this module is the receiver — so its failure loses all four at once.

That is the diagnostic distinction. All four wheels reporting nothing points at the receiver or its antenna; one wheel missing points at that sensor. A single missing wheel is nearly always a sensor whose battery has expired, which happens after several years and is a wear-out rather than a fault.

Indirect systems have no sensors at all, deriving pressure from wheel speed differences through the braking module, so on those there is no module to replace and the fault is elsewhere. Establish which type the vehicle uses first. Sensors must be registered after a wheel change or rotation on many direct systems, and an unregistered sensor reads exactly like a failed one.