Ignition

P0355 — Ignition Coil E Primary/Secondary Circuit Malfunction

Severity: medium Drive with care, to a shop

What P0355 means

The engine control module monitors the electrical circuit of ignition coil E, which on most engines serves cylinder 5. Normally the coil builds energy in its primary winding, and the module interrupts the current at the right moment so the secondary winding fires the spark plug. P0355 sets when the module sees an open, a short to ground or voltage, or an incorrect signal in that circuit.

Symptoms

  • Check engine light on (may flash during misfires)
  • Engine misfire, often on cylinder 5
  • Rough idle
  • Loss of power or hesitation under load
  • Jerking during acceleration
  • Worse fuel economy or a fuel smell from the exhaust

Possible causes

  1. Failed ignition coil E (cylinder 5)
  2. Damaged, corroded or loose coil connector
  3. Wiring harness damage: open circuit, chafed insulation, short to ground or voltage
  4. Missing power or ground at the coil (fuse, relay, bad terminals)
  5. Worn spark plug or wide gap overloading the coil
  6. Failed coil driver inside the engine control module (rare)

How to diagnose

  1. Scan for codes and freeze frame data, and check for related misfire codes such as P0305
  2. Inspect coil E and its connector for moisture, carbon tracking, melting, cracks and corroded terminals
  3. Swap coil E with a neighboring cylinder's coil, clear the code and see whether the fault follows the coil
  4. Inspect the spark plug in that cylinder for wear, gap and oil fouling
  5. Measure primary and secondary winding resistance and compare with the manufacturer's specification
  6. Check for power and ground at the coil connector with the ignition on
  7. Test the control wire from the coil connector to the module for opens and shorts
  8. Use a scope or noid-style test light to confirm the module is sending trigger pulses

Common fixes

  • Replace ignition coil E (and the worn spark plug if needed)
  • Replace the spark plug in that cylinder
  • Repair the wiring harness or replace the damaged connector
  • Fix the power or ground supply problem (fuse, terminal)
  • Repair or replace the engine control module if the coil driver has failed

P0355 on different brands

Ford · manuals
Ford uses an extended P0355:11 format on 2024–2025 gasoline engines, meaning a short to ground detected by the ignition coil control monitor; it describes the detected condition rather than a confirmed failed part.

Questions and answers

What does P0355 mean?

It means the engine control module found a fault in the primary or secondary circuit of ignition coil E, typically for cylinder 5.

Can I drive with code P0355?

Only briefly and under light load. If the check engine light flashes, stop driving, because the misfire can damage the catalytic converter.

Will replacing the coil fix P0355?

Often, but not always. Check the connector, wiring, power supply and spark plug first, or the new coil may fail again.

This is general information about the code. The meaning can differ between makes and models: a scan tool and the repair manual for your car will show the exact cause.