P0355 moderate

Ignition Coil E Primary/Secondary Circuit Malfunction (Cylinder 5)

The P0355 code means the vehicle's onboard diagnostic system has detected: Ignition Coil E Primary/Secondary Circuit Malfunction (Cylinder 5). This is a moderate severity code.

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Keep driving?: Short distances only
DIY difficulty: easy
Estimated cost: $50 - $350 (parts and labor)

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Common Symptoms

Engine misfire on cylinder 5
Rough idle on V6 or V8 engine
Check Engine Light illuminated or flashing
Reduced power
Exhaust smells of unburned fuel

Probable Causes (Ranked by Likelihood)

Faulty ignition coil on cylinder 5 Very High
Worn or fouled spark plug on cylinder 5 High
Damaged coil connector or wiring High
PCM coil driver circuit failure for cylinder 5 Moderate
Cracked coil boot causing spark leak Low

Step-by-Step Diagnostic Procedure

Swap cylinder 5 ignition coil with another cylinder and clear codes to test
Inspect the spark plug on cylinder 5 for wear or damage
Measure coil resistance values and compare to specification
Check coil connector and spark plug well for contamination or damage
Test PCM coil driver signal at the connector

Frequently Asked Questions

Can I drive with code P0355?

You can drive short distances. On V6 and V8 engines, one dead cylinder is less noticeable than on a 4-cylinder, but repair is still needed to prevent catalytic converter damage.

Is cylinder 5 hard to reach on V-engines?

On many V-engines, cylinder 5 is on the rear bank near the firewall, which can make coil and plug replacement more challenging. Some vehicles require removing the intake manifold or other components.

Can I use aftermarket ignition coils?

Quality aftermarket coils work fine for most applications. However, some vehicles (particularly European makes) are sensitive to coil quality. OEM or premium aftermarket coils are recommended for these vehicles.