P2CBCFan 3 Overspeed
- Generic OBD-II code · Powertrain
- Turns on the check-engine light
- Matters for the ITP
- Needs a drive cycle to confirm a fix
- How the car detects it
- P2CBC is the counterpart to P2CBB: the third cooling fan turns noticeably faster than the controller expects for the present request. No manufacturer publicly documents this code. The closest published logic is GM's: table 23OBDG07 flags fan 2 overspeed as P2CBA when the reported speed exceeds the estimate by 1400 to 4050 rpm for 20 s, and treats fan 3 the same way under its own code P14D8 with a margin of 1300 to 4800 rpm. GM's 2025 diesel table watches the LIN fan 3 for underspeed and for readings of 4000 rpm or more, but assigns no P2CBC. CARB requires output devices such as fans to be checked for correct response to their commands. A damaged rotor, a fan module running at full power or false speed feedback would explain the fault. Overspeed is rarely a cooling risk but hints at a component that will fail.
- What you may notice
- Check engine light, depending on the maker
- Loud or rough fan noise
- Likely causes
- PossibleFan 3 blade broken or rotor unbalanced
- PossibleFan 3 electronics ignore the speed command
- RareWrong speed value reported by the fan module
- Inspection (ITP)
- Matters for the ITP. While the check-engine light is on, the car fails the emissions check.
- Repair
- Hard · Usually a job for a workshop.Typical cost: €100 – €1,600
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.