P0355

What it means

P0355 means the engine control unit has detected a fault in the primary control circuit of ignition coil E, which is the fifth coil in the manufacturer's numbering. The ECU monitors the coil driver signal, and it set the code because the circuit looked open or did not respond as expected when the coil was commanded to fire. Which cylinder coil E serves depends on the engine and manufacturer.

Symptoms

• Engine misfire, especially under load or acceleration
• Rough or unstable idle
• Malfunction indicator lamp on, possibly flashing during a severe misfire
• Hesitation or loss of power
• Hard starting or occasional stalling
• Poor fuel economy

Possible causes

• Faulty ignition coil E (internal open circuit in the primary winding or integral driver)likely
• Damaged, corroded or loose coil connector or terminalslikely
• Open circuit or high resistance in the wiring between the coil and the ECU (control wire, power or earth)possible
• Blown fuse or fault in the ignition coil power supplypossible
• Wiring chafed against engine parts or damaged by heat or oil contaminationpossible
• Fault in the ECU coil driverrare

How to diagnose

1. Read all stored and pending codes and the freeze frame data, noting engine load, speed and temperature when the fault set. Check for other misfire or coil codes.
2. Find out which cylinder coil E serves on this engine using the manufacturer's data, as the numbering varies by model.
3. Visually inspect the coil, connector and wiring for damage, oil, water ingress, corrosion, heat damage or chafing.
4. Check the relevant fuses and the coil power and earth supplies with a multimeter.
5. Swap coil E with a known-good coil from another cylinder, clear the code and see whether the fault follows the coil.
6. Check continuity and resistance of the control wire between the coil connector and the ECU connector with the battery disconnected, referring to the wiring diagram.
7. Use a scope or the manufacturer's data to check the coil control signal is present and correct when the engine is cranked.
8. Inspect the spark plug for that cylinder, as a worn plug can stress and damage a coil.

How to fix

• Replace the faulty ignition coil and inspect or replace the spark plug for that cylinder.
• Repair or replace damaged connector terminals and clean any corrosion.
• Repair or replace the damaged wiring section, using proper soldered and sealed joints.
• Replace a blown fuse after finding and fixing the cause of the overload.
• Have the ECU tested and repaired or replaced only after all wiring and coil faults have been ruled out.

Can I keep driving?

Nearby codes

• P0354GenericIgnition Coil D Primary Control Circuit/Open
• P0356GenericIgnition Coil F Primary Control Circuit/Open