Powertrain, generic (extended)

P2CBC Fan 3 Overspeed

Check engine lightOn
EmissionsRelevant
Drive cycleRequired
Limp modeNo

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.

Likely causes

Fan 3 blade broken or rotor unbalanced
Fan 3 electronics ignore the speed command
Wrong speed value reported by the fan module

Symptoms

  • Check engine light, depending on the maker
  • Loud or rough fan noise

Repair estimate

DifficultyHardWorkshop job
Parts and labour€100–1,600
Time0.5–9 h

Typical range across vehicles; the real cost depends on what the testing finds.

Parts involved

cooling fan 3

Related codes

P2CBBP2CBAU067CP0495P2C41

References: law.cornell.edu, gsi.ext.gm.com, gsi.ext.gm.com.