P2301
Ignition Coil A Primary Control Circuit High
The primary control circuit of ignition coil A reads a voltage above the expected level — typically an open primary circuit or a short to battery voltage on the primary control wire. The ECU sees no normal current flow, coil A does not fire, and the cylinder misfires. Causes: an open or disconnected primary wire, an internal open in the coil, or a faulty ECU driver.
- Check engine light: Yes
- Emissions related: Yes
- Repair difficulty: easy
Common causes
Ordered by how often each turns out to be the cause.
- Primary wire shorted to batteryCommon
- Open primary windingPossible
- Connector pins corroded - high contact resistanceLess likely
Parts involved
- Ignition Coil
- Coil Driver
- Ignition Wiring
P2301 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.