P2321

The primary control circuit of ignition coil H reads a voltage below the expected level — usually a short to ground on the primary driver wire or a low-resistance fault in the coil primary winding. Coil H cannot build a normal charge, so the cylinder it fires misfires, especially under load. Causes: short to ground in the primary wiring, an internal coil primary fault, or a faulty ECU/igniter driver.