P2B31 code meaning
Fan 2 Performance/Stuck Off
Powertrain system Generic code P2Bxx codes Check engine light
What P2B31 means
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.
P2B31 at a glance
- Check engine lightYes, usually on
- Emissions testCan fail
- Limp modePossible
- Repair difficultyMedium, DIY possible
- Typical labor0.3 to 2.5 hours
- Clears after repairAfter a drive cycle
Symptoms of P2B31
- MIL or cooling warning
- Temperature climbing at high load or with A/C on
Common causes of P2B31
- Most likelyFan 2 motor worn, seized or jammed by debris
- PossibleFan module or relay for fan 2 not switching on
- Less likelyWeak supply or ground to fan 2
Check the most likely causes first. Replacing parts by guesswork is the most expensive way to clear a code.
Parts involved
Cooling fan 2Fan relay 2ECM
What each part of P2B31 means
| P | Powertrain system: engine, fuel system, ignition, emissions and transmission. |
| 2 | Generic code (second SAE range): it means the same on every make. |
| B | Area: hybrid propulsion. |
| 31 | The exact fault in that area. |
What to do next
- Note P2B31 and any other codes stored with it: several codes together often point to one cause.
- Check for loose connectors and damaged wiring around the parts the code names.
- Check open recalls for your car: some faults are fixed for free by the dealer. Enter your VIN.
- Clear the code only after the repair. If it comes back, the fault is still there.
Buying a used car? Scan it for stored codes before you pay. A recently cleared memory can hide a problem.
Questions about P2B31
What does P2B31 mean?
P2B31 means "Fan 2 Performance/Stuck Off". 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. It is a generic code, so it means the same on every make.
Is it safe to drive with P2B31?
Drive gently and only to a workshop. With P2B31 the car can go into limp mode (reduced power) to protect itself.
Will P2B31 fail an emissions test?
Yes, it can. P2B31 is emissions-related, so most inspection programs fail a car while it is stored or while the check engine light is on.
How hard is P2B31 to fix?
Difficulty: medium. A typical repair takes 0.3 to 2.5 hours of work. A careful DIY repair is possible with basic tools and a scanner.
Will P2B31 clear itself after the repair?
After the repair the car has to complete a drive cycle (a mix of city and highway driving) before the test runs again. Until then the readiness monitor shows "not ready", which can fail an inspection.