C123EF0 on an Audi Q5 FY is a brake-electronics fault that should be investigated promptly. Owners may see ABS, traction-control or brake-system warnings, including messages connected with hydraulic brake-booster pressure. The code is associated with Bosch ESP9-family ABS pump/module systems fitted to selected Audi, Porsche and Volkswagen applications.

Possible Audi Q5 C123EF0 symptoms

• ABS and traction-control lamps illuminated
• Brake-system warning displayed
• Hydraulic brake-booster pressure fault in diagnostics
• Reduced availability of ABS, ESP or emergency-braking assistance

Confirm the exact Q5 module

Not every Q5 uses the same ABS pump/module. The repair listing includes Q5 applications from 2016–2020, including the part-number family 80A907379E / Bosch 0265956241. This is a guide only: check the label on the original pump/module and the diagnostic report before booking a repair.

What should be checked before repair?

Ask a suitably qualified technician to record all ABS fault codes and examine the power supply, earths, connectors and wiring. Brake hydraulic concerns and other related faults should be assessed as part of the diagnosis. Do not clear a code and assume the issue has been fixed if warning lamps return.

Audi Q5 ABS pump/module repair

When testing confirms an internal fault, Essex Recons can test, repair and return the original ABS pump/module. Keeping the original unit can help avoid unnecessary uncertainty associated with a used replacement and its compatibility.

View the C123EF0 ABS pump repair service

Safety note

ABS and stability-control faults are safety-critical. Drive only in accordance with professional advice and do not undertake brake-system work without the correct training, equipment and manufacturer procedure.

FAQ

Is C123EF0 specific to the Audi Q5?

No. It can occur on several Bosch ESP9-family ABS applications. The vehicle and module part number identify whether this service is suitable.

Why do I need the ABS pump number?

It confirms the exact variant, as part numbers vary by specification and model year.