A steady ABS warning on your Cayenne III is usually a wheel speed sensor, its wiring, or the magnetic trigger ring in the hub — not the ABS module itself. Here is the check order a Porsche technician uses, and how gently you should drive until it is sorted.
First, What That Steady ABS Light Means
On your Cayenne III, an ABS lamp that stays on from the moment you start the car until you switch it off is the control unit telling you it has lost a signal it trusts. Unlike a brief flicker over rough pavement, a continuous light almost always means a stored fault — the ABS module has logged something like an implausible wheel speed signal or an open circuit, and it has parked the system until it is repaired. You will often see the PSM light alongside it, and sometimes messages about hill hold or all-wheel-drive assistance, because those systems all borrow the same four wheel speed readings.
