P2257
Secondary Air Injection System Control A Circuit Low
The control circuit of the secondary air injection system A reads a voltage below specification. Either the relay output is shorted to ground or the wiring/load is faulty.
- Check engine light: Yes
- Emissions related: Yes
- Repair difficulty: medium
Common causes
Ordered by how often each turns out to be the cause.
- Control wire shorted to groundCommon
- Faulty SAI relayPossible
- Connector pins corroded - high contact resistanceLess likely
Parts involved
- Secondary Air Pump
- Sai Relay
- Sai Wiring
P2257 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.