Powertrain, generic (extended)

P2C42 Fan 4 Performance/Stuck Off

Check engine lightOn
EmissionsRelevant
Drive cycleRequired
Limp modePossible

P2C42 reports that the fourth fan output does not deliver what is asked of it: the fan stays still or reaches far too little speed while its control line shows no electrical fault (those would be P2C3E to P2C40). No manufacturer publicly documents P2C42. Which part is fan 4 varies: a further radiator fan stage, an auxiliary fan for a charge air or oil cooler, or an engine compartment blower like the pair Porsche fits to the rear-engined 911, whose failure brings a warning to avoid full engine load. Mechanical blocking by dirt, as Audi found on the e-tron GT, worn bearings and a failed fan electronics module are the usual causes. Clean and spin the fan by hand before replacing parts. Fan 3 has P2C41, fan 2 P2B31.

Likely causes

Fan jammed by debris or a damaged shroud
Worn bearings or corroded motor
Integrated fan electronics or fan module failed

Symptoms

  • Temperature warning or reduced power under high load
  • Fan 4 does not turn when activated with a scan tool
  • Grinding noise before the fan stops

Repair estimate

DifficultyMediumWorkshop job
Parts and labour€80–800
Time0.5–3 h

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

Parts involved

cooling fan 4fan relay 4ecm

Related codes

P2C3EP2C3FP2C40P2C41U067DP2B31

References: law.cornell.edu, static.nhtsa.gov, static.nhtsa.gov.