// Official meaning
Wear detection / pressure regulation fault — the SBC unit has detected a problem on the pressure-sensing or pressure-regulation side of the system.
// On the bench
C235A is one of the cluster of SBC codes (C235A, C235C, C235D, C235E, C2359) we have been repairing since our earliest W211 write-ups. Unlike the C249F counter, these point at real components inside the pump — here the pressure sensor or regulation circuit. A reset is not a fix for this family of codes.
How it shows up
- SBC warning message on the dash
- Code returns after clearing
- May appear with other C235x codes
What fixing it involves
Three honest routes, all through our dedicated SBC workshop at sbc-repair.com: a counter reset (£120 — nothing replaced, only right if the pump tests healthy), a full rebuild of your own unit (£430, 6-month warranty), or an exchange pump (£700, 12-month warranty, no core return). Complete on-car service — repair, reprogram, bleed and initialise — from £650.
Frequently asked questions
Is C235A the same as the lifetime-counter message?
No. C249F is a service counter; C235A is the unit reporting a fault on its pressure-sensing/regulation side. It needs the pump opened up and repaired, not just reset.
Can my SBC unit be repaired or does it need replacing?
Most can be rebuilt — £430 on your own unit with a 6-month warranty. If yours is beyond saving we supply an exchange pump at £700 with no core return needed. We tell you straight which it is after testing.