P0355
Ignition Coil "E" Primary/Secondary Circuit
An electrical fault is detected in both the primary and the secondary circuit of ignition coil E. The ECU cannot drive the coil correctly, so the cylinder served by coil E misfires or does not fire at all. Causes: an open or shorted primary control wire, an internal coil winding fault, a failed igniter/driver, or wiring or connector damage at the coil.
- Check engine light: Yes
- Emissions related: Yes
- Repair difficulty: easy
What we see in the workshop
ON FORD ECOBOOST
Ignition coil circuit faults on EcoBoost engines are usually the coil or its connector, which suffers in engine-bay heat.
Common causes
Ordered by how often each turns out to be the cause.
- Ignition coil failedCommon
- Wiring/connector faultPossible
Parts involved
- Ignition Coil
- Coil Wiring
P0355 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.