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.
Affected components
- Ignition coil
- Coil driver
- Ignition wiring
Common causes
- High likelihood: Primary wire shorted to battery
- Medium likelihood: Open primary winding
- Low likelihood: Connector pins corroded - high contact resistance
Diagnostic notes
- The malfunction indicator lamp may illuminate
- This code can affect emissions
- A drive cycle may be required after repair
Related codes
Sources
Diagnostic information is provided for reference only. Confirm the code with a compatible scan tool and follow the vehicle manufacturer's service procedures before replacing components.