P2B86
Coolant Pump A Overspeed/Air in System
The coolant pump A runs above the calibrated maximum speed without producing the expected flow. Indicates air pocket in the coolant loop.
- Check engine light: Yes
- Emissions related: No
- Repair difficulty: medium
Common causes
Ordered by how often each turns out to be the cause.
- Air pocket in coolant loopCommon
- Coolant level lowPossible
Parts involved
- Coolant Pump A
- Engine Coolant Loop
P2B86 is a generic OBD-II code defined by SAE J2012. Exact wording and diagnostic procedure vary by manufacturer and model. Code definitions are drawn from the public-domain OBDex dataset; the workshop notes are our own.