Mercedes M Klasse Hybrid Tire Pressure Problems

A flat tire itself is unlikely to cause all those symptoms simultaneously. The ABS light, vibrating steering, and power steering issues suggest a more complex problem potentially linked to the tire pressure monitoring system (TPMS) or even a related sensor malfunction. Have you checked the actual tire pressure with a tire gauge, not just relying on the dashboard warning? It's possible a faulty TPMS sensor is triggering the warning and simultaneously interfering with other systems. Is the shaking constant, or does it worsen at certain speeds? Does the steering get harder at all speeds, or just low speeds?

I checked the tire pressure with a gauge, and one tire was indeed low. I'm struggling with understanding how a low tire could cascade into ABS and power steering malfunctions. Could a defective valve in the tire be the culprit, perhaps causing a slow leak and triggering a chain reaction of sensor errors?

A defective valve causing a slow leak leading to low pressure is certainly plausible. Modern vehicles rely heavily on interconnected electronic systems. The TPMS reports low pressure, which, in turn, could theoretically affect ABS and power steering if the system is designed to compensate for perceived instability due to tire pressure differences. While it seems far fetched, the electronic control unit may interpret the data incorrectly. It is time to have the tire and TPMS checked by a qualified technician. It could be a simple fix but these symptoms together warrant a professional diagnosis.

You were spot on. Took it to the workshop, and it turned out to be a defective valve stem in the tire causing a slow leak. The TPMS going haywire triggered the cascade of errors with the ABS and power steering. New valve stem, tire re-inflated, sensors reset, and all is well. Total cost: 280€.