// Official meaning
Internal fault — a general internal SBC unit fault requiring inspection.
// On the bench
The least specific of the SBC family: the unit knows something is wrong inside but cannot say exactly what. On the bench it usually resolves into one of the usual suspects — motor, relay, valves or electronics — once the unit is opened and tested properly.
How it shows up
- SBC warning message on the dash
- Code returns after clearing
- Often stored with other C235x / C249F 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
How do you diagnose a general internal fault?
On the bench, with the unit tested properly — not by guessing from the code alone. C2359 nearly always resolves into a specific motor, relay, valve or electronics fault once we have it open.
What does the repair cost?
Rebuild of your own unit £430 (6-month warranty), exchange pump £700 (12-month, no core return), or the complete on-car service from £650 via sbc-repair.com.