GLC Hybrid Tire Pressure Warning and ABS Issues

I had a similar experience with my GLC. The symptoms are highly suggestive of a failing TPMS (Tire Pressure Monitoring System) sensor. Have you checked the actual tire pressure with a manual tire gauge? Sometimes the onboard system can be inaccurate. A punctured tire, even a slow leak, will cause low tire pressure and trigger the warning. The ABS and power steering issues might be related if the system is detecting a significant pressure difference between tires. What do the individual tire pressure readings say on the display? It could be a defective valve within the tire itself.

I did a quick visual, didn't see anything obvious. You mentioned a 'defective valve'. Is that something the system would specifically flag or just a general cause for pressure loss?

The system won't flag a defective valve directly. The TPMS only monitors pressure. A slow leak from a valve stem, especially if it's corroded or damaged, will gradually lower the tire pressure, triggering the low tire warning. The system reports pressure; it doesn't diagnose the cause of the pressure loss. Given the ABS light and steering issues along with the tire pressure warning, I'd recommend getting it checked by a workshop promptly. It's likely a combination of factors stemming from the tire issue.

Confirmed. Defective valve in the tire. Replaced it, along with a new sensor as a precaution. All warnings cleared, steering is back to normal. Total cost 280€. Thanks for the insight.