Powertrain, generic (extended)

P2B31 Fan 2 Performance/Stuck Off

Check engine lightOn
EmissionsRelevant
Drive cycleRequired
Limp modePossible

P2B31 is the functional code for a second radiator fan: its circuits test fine (otherwise P0481, P0693 or P0694 would be set), yet the fan turns too slowly or not at all when commanded. Twin-fan cooling packs usually run fan 2 for high load or A/C demand, so a failure tends to show up only in heat or traffic. No manufacturer documents P2B31 publicly. FCA's 2.0 L Alfa Romeo models use the fan 1 sibling P2B2F with the MIL, and Audi's e-tron GT bulletins show how debris from the wheel housing can jam either of its two fans. CARB requires output components to be monitored for functional response where feasible. A worn motor, blocked blades or a fan module that stays off are the likely causes. Expect rising temperatures under load. Its stuck-on twin is P2B32.

Likely causes

Fan 2 motor worn, seized or jammed by debris
Fan module or relay for fan 2 not switching on
Weak supply or ground to fan 2

Symptoms

  • MIL or cooling warning
  • Temperature climbing at high load or with A/C on

Repair estimate

DifficultyMediumDIY possible
Parts and labour€20–600
Time0.3–2.5 h

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

Parts involved

cooling fan 2fan relay 2ecm

Related codes

P2B32P2B2FP0481P0693P0694P2CB9

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