P2259
Secondary Air Injection System Control B Circuit Low
The drive line for secondary air injection (AIR) control circuit B is stuck low. Secondary air is pumped into the exhaust manifold during cold start to speed up catalyst light-off.
- Check engine light: Yes
- Emissions related: Yes
- Repair difficulty: medium
Common causes
Ordered by how often each turns out to be the cause.
- Short to groundCommon
- Connector pins corroded - high contact resistanceLess likely
- Harness chafing through insulationLess likely
Parts involved
- Secondary Air Injection Pump
- Secondary Air Injection Valve
P2259 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.