P2B28Hybrid/EV Battery Pack Coolant Pump A Performance
- Generic OBD-II code · Powertrain
- Turns on the check-engine light
- Matters for the ITP
- Can trigger limp mode
- Needs a drive cycle to confirm a fix
- How the car detects it
- P2B28 means battery coolant pump A is electrically reachable but does not perform as the battery controller expects. VW and Audi store P2B2800 in battery management J840: VW bulletin 93-21-02 (2021 ID.4) traces it to air left when pump V590 did not run during the fill-and-bleed routine, and Audi's 2068363 series (Q4 e-tron 2022–2024, message Electric drive fault) names dry running from residual air, prescribes two bleed runs with the battery at 3–35 °C and replaces V590 only if the entry stays static. FCA lists P2B28 with MIL on the Jeep Wrangler eTorque mild hybrids (2.0 L, 3.6 L) and reflashes the battery pack module or hybrid control processor. Thresholds are not published. The dry-run code is P2B29, a stalled pump P0CFF.
- What you may notice
- Electric drive fault message or MIL
- Reduced drive or charging power
- Short or missing engine auto-stops on mild hybrids
- Likely causes
- LikelyResidual air in the battery coolant loop, often after service
- PossibleBattery or hybrid controller software needing an update
- PossibleWorn or failing battery coolant pump
- RareLow coolant level from a leak
- Inspection (ITP)
- Matters for the ITP. While the check-engine light is on, the car fails the emissions check.
- Repair
- Medium · Usually a job for a workshop.Typical cost: €50 – €900
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.