P0355 — Ignition Coil E Primary/Secondary Circuit Malfunction

What does P0355 specifically identify?

P0355 identifies a primary or secondary circuit malfunction involving the ignition coil designated E. It can be caused by the coil, its wiring, the related spark plug, or the secondary lead rather than by the coil alone.

Does ignition coil E always mean cylinder 5?

No. The letter E may correspond to the fifth coil position, but cylinder assignments differ by vehicle. Confirm the coil E location and cylinder number using the VIN-specific service information before testing or replacing parts.

Can the vehicle be driven with P0355 stored?

Limited driving may be possible if the engine runs smoothly and power is normal, but P0355 can accompany a damaging misfire. Avoid sustained high-load operation and stop driving if severe shaking, power loss, or a flashing warning light occurs.

Will replacing ignition coil E always clear P0355?

Not always. A new coil will not correct an open power wire, corroded connector, damaged control circuit, defective spark plug, or arcing secondary lead. Test those items before replacing the coil and verify the repair by rescanning for P0355.

When your engine control unit detects a problem with the ignition coil labeled "E" — whether in its primary circuit, secondary circuit, or the logic that drives it — it logs trouble code P0355. This code falls under the powertrain category, meaning it relates directly to engine and transmission operation. The ignition coil's job is to transform the battery's low voltage into the thousands of volts needed to create a spark at the spark plug. On many modern engines, a single coil pack serves multiple cylinders, and each cylinder gets its own numbered circuit. Circuit E corresponds to a specific cylinder, and when that circuit fails the self-test, P0355 triggers.

Unlike a simple open or short circuit code, P0355 tells you the module compared live sensor data against its programmed parameters and found an abnormality. This could stem from the coil itself, the wiring feeding it, the connector, or even the engine control module's driver circuitry. The ECU typically needs to see the fault persist across multiple drive cycles before lighting the Check Engine lamp, and it stores a freeze frame snapshot capturing RPM, engine load, coolant temperature, and vehicle speed at the moment of failure. That snapshot is your best starting point for diagnosis.

Symptoms of P0355

• Check Engine Light illuminated
• Engine misfires, either under load or while idling
• Noticeable loss of engine power or hesitation during acceleration
• Rough running and jerking motions
• Increased fuel consumption compared to normal
• Difficulty starting, especially in damp or wet conditions
• In severe cases, the engine may run on fewer cylinders

Common Causes

• Failed or failing ignition coil E (internal windings shorted or open)
• Damaged wiring or corroded connector at the coil circuit
• Short or open in the primary ignition control circuit
• Intake valve cover gasket leak allowing oil to enter the spark plug well
• Moisture contamination in the ignition coil or boot area
• Worn, fouled, or incorrectly gapped spark plugs
• Engine control module driver fault or software calibration issue

How to Diagnose P0355

1. Connect an OBD2 scanner and confirm P0355 is present. Record the freeze frame data before clearing anything — this tells you the exact operating conditions when the fault occurred.

2. Pull all stored codes. Related misfire codes (P0300–P0308 range) often point to the failing cylinder, and any powertrain control module faults can explain why the coil circuit test failed in the first place.

3. Perform a visual inspection of the wiring harness and connector at ignition coil E. Look for chafed wires, broken insulation, corrosion, or loose terminals. Tug gently on each wire to check for intermittent opens.

4. If your scanner supports bi-directional controls or actuator tests, command the coil on and off while monitoring its operation. A coil that produces no spark during the test is almost certainly failed.

5. Swap the suspected coil with a known-good coil from another cylinder. Clear the code, drive the vehicle under similar conditions, and see if P0355 moves to a different cylinder. If the fault travels with the coil, the coil itself is bad.

6. Remove and inspect the spark plugs in the affected cylinder. Check for oil fouling, carbon buildup, wet tips, or gaps outside manufacturer specs. Replace as needed.

Repair Options and Costs

• Replace spark plugs: $90–$250
• Repair or replace damaged coil wiring harness or connector: $80–$250
• Replace ignition coil E: $150–$380

All prices reflect parts and labor at independent shop rates in USD.

Total Repair Cost

The total bill hinges entirely on what component is actually at fault. In most cases, P0355 stems from a failed ignition coil, landing the repair somewhere between $150 and $380. Wiring issues typically run $80 to $250 depending on whether you need a simple connector repair or a full harness section. Spark plug replacement alone rarely exceeds $250. Always diagnose before buying parts — swapping an expensive coil when the real issue is a $20 connector is an avoidable mistake.

Can You Drive with P0355?

Drive with caution. Persistent misfires from an ignition fault send unburned fuel into the exhaust, and that raw fuel overheats the catalytic converter, potentially causing irreversible damage that costs thousands to repair. If the Check Engine Light is flashing rather than steady, stop driving immediately and address the problem. Even steady illumination means get it diagnosed soon — not tomorrow, not next week.

Related OBD2 Codes

• P0300: Random/Multiple Cylinder Misfire Detected
• P0301: Cylinder 1 Misfire Detected
• P0302: Cylinder 2 Misfire Detected
• P0303: Cylinder 3 Misfire Detected
• P0304: Cylinder 4 Misfire Detected
• P0305: Cylinder 5 Misfire Detected