ABS Software and Fault Code C123EF0 – Hydraulic Brake Booster Limit Value Reached

1. Introduction

Modern automotive safety systems rely heavily on the Anti-Lock Braking System (ABS) integrated with electronic control logic (often referred to as ABS/ESP/ESC software). These controllers continuously monitor braking performance, hydraulic pressures, vacuum supply, and sensor feedback to maximize braking efficiency while preventing wheel lock-up near the limits of grip.

One fault of significant concern in many VAG-platform vehicles (e.g., Audi, VW, Porsche, Lamborghini, Bentley) is the Diagnostic Trouble Code (DTC) C123EF0 — Hydraulic Brake Booster Limit Value Reached. This fault often results in an irreversible ABS condition that impacts brake assist functionality.


2. What Is C123EF0?

The code C1

...