P0355 Ignition coil E primary or secondary circuit fault (the coil for cylinder 5 on most engines)

Ignition Coil E Primary/Secondary Circuit Malfunction

P0355 in short

P0355 means the computer found a fault in the primary or secondary circuit of ignition coil E, usually the cylinder 5 coil. A failing coil, its connector or wiring, or a worn spark plug is the usual cause. You can drive gently if the light is steady, but stop if it flashes.

Each cylinder has an ignition coil that turns battery voltage into the spark. The computer watches the coil circuit, and P0355 sets when the circuit for coil E does not behave as expected. Coil E is usually cylinder 5, but the lettering depends on the engine, so check the service information.

The most common causes are the coil itself, its connector, or a worn spark plug that makes the coil work harder. Ford has two bulletins that name this code: one for coil-on-plug damage on 2006 to 2008 Fusion, Milan, Edge and related models, and one for an open circuit in the coil connectors on 2014 to 2016 F-250 and F-350 trucks with the 6.2L V8.

PartsAvatar also warns that vacuum leaks and carbon build-up can be mistaken for a coil fault, so check for those before replacing parts.

Most likely causes

  1. Failed ignition coil on cylinder 5

    Common general cause
    Why it ranks here
    The code names the coil E circuit, and PartsAvatar lists a faulty coil as the first cause. Ford TSB 13-4-17 also ties P0355 to damaged coil-on-plug units on some 2006 to 2008 models.
    What would change this
    Rises if the code follows the coil when it is swapped with another cylinder. Falls if the code stays with cylinder 5.
    How to test the ignition coil

  2. Open circuit or damaged coil connector

    Supported by vehicle data
    Why it ranks here
    Ford TSB 18-2047 says P0355 and P0356 on 2014 to 2016 F-250 and F-350 6.2L trucks can come from an open circuit in the cylinder 5 and 6 coil connectors, caused by interference with the intake air expansion resonator. PartsAvatar also lists open or shorted wiring.
    What would change this
    Rises if the connector is loose, pushed by the resonator, or shows a broken circuit. Falls if wiring and connector test fine.

  3. Worn or fouled spark plug

    Common general cause
    Why it ranks here
    PartsAvatar lists defective spark plugs among the causes, and a worn plug makes the coil work harder.
    What would change this
    Rises if the plugs are overdue or have a wide gap or heavy deposits. Falls if they are in good condition.
    How to test the spark plug

  4. Vacuum leak or carbon build-up making the cylinder run poorly

    Possible — needs testing
    Why it ranks here
    PartsAvatar warns that parts are often replaced before vacuum leaks and throttle body or air passage carbon are checked, so they are worth ruling out.
    What would change this
    Rises if other lean or idle codes are stored. Falls if the intake holds smoke and trims are normal.

What to test first

Start at step 1. Each result tells you what it means and where to go next.

  1. Read all stored codes and freeze-frame data, and note whether the check engine light has been flashing.

    Low riskTool: OBD-II scan tool

    • IfP0356 or other coil codes are stored too

      It meansMore than one coil circuit is affected, so look at shared wiring and the bulletins.

      Go to step 2

    • IfOnly P0355 is stored

      It meansInspect the cylinder 5 coil connector and plug.

      Go to step 3

  2. Ask a dealer whether your VIN has a coil connector or coil-on-plug bulletin. Ford has them for 2006-2008 Fusion, Milan, Edge, Taurus, MKZ and MKX, and for 2014-2016 F-250/F-350 6.2L.

    Low risk

  3. With the engine off and cool, look at the cylinder 5 coil connector, wiring and spark plug for damage, looseness or oil, then swap the coil with a neighbor and clear the codes.

    Use cautionTool: basic hand tools, scan tool

    Warning:Never touch coils, plug wires or connectors while the engine is running or cranking; ignition voltage can shock you. Let the engine cool before touching exhaust-side parts.

Symptoms

  • Check engine light on
  • Rough idle or hesitation
  • Misfire or loss of power under load
  • Hard starting
  • Check engine light flashing Gets more serious: stop and have it checked.

Compare with: Rough idle with the check engine light on, Car shaking with the check engine light on

How to fix

  1. With the engine off and cool, check that the cylinder 5 coil connector is fully seated and not damaged.

  2. Ask a dealer whether your VIN is covered by a coil or connector bulletin before replacing coils.

Parts and cost context

  • Ignition coil:Swap the coil with another cylinder first so you replace the right one. If the plugs are old, replace them with the coil. Labor varies; get a quote.

Labor varies by vehicle and shop; get a quote before you approve a repair.

Compare used part prices on PartPriceGuide

On your vehicle

Ford

  • 2014–2016 · F-250 Super Duty · 6.2L V8

    Supported by vehicle data

    Ford bulletin 18-2047 says 2014 to 2016 F-250 and F-350 trucks with the 6.2L V8 can set P0355 or P0356 from an open circuit in the cylinder 5 and 6 coil connectors, caused by contact with the intake air expansion resonator. Whether it is still current is not verified.

  • 2006–2008 · Fusion

    Supported by vehicle data

    Ford bulletin 13-4-17 links P0351 to P0355 on 2006 to 2008 Fusion, Edge and Taurus to damaged coil-on-plug units. Whether it is still current is not verified.

  • TSB18-2047Status unverified

    MIL with P0355 and/or P0356, 6.2L: open circuit in coil-on-plug connectors, cylinders 5 and 6

    2014–2016f-250-super-duty, f-350-super-duty · NHTSA 10136577

    Open circuit in the cylinder 5 and 6 coil connectors caused by interference with the intake air expansion resonator; follow the service procedure.

    We couldn't confirm whether this bulletin is still current, so it doesn't count as confirmation.

  • TSB-13-4-17Status unverified

    MIL with P0351-P0355 and coil-on-plug damage

    2006–2008fusion, edge, taurus · NHTSA 10052190

    Some vehicles with P0351 to P0355 may have one or more damaged coil-on-plug units. The NHTSA summary does not give the repair steps.

    We couldn't confirm whether this bulletin is still current, so it doesn't count as confirmation.

Lincoln

  • 2006–2008 · MKZ

    Supported by vehicle data

    The same Ford bulletin 13-4-17 covers the Lincoln MKZ and MKX with P0351 to P0355 and coil-on-plug damage. Whether it is still current is not verified.

  • TSB-13-4-17Status unverified

    MIL with P0351-P0355 and coil-on-plug damage

    2006–2008fusion, edge, taurus · NHTSA 10052190

    Some vehicles with P0351 to P0355 may have one or more damaged coil-on-plug units. The NHTSA summary does not give the repair steps.

    We couldn't confirm whether this bulletin is still current, so it doesn't count as confirmation.

  • TSB-13-4-17 (Lincoln)Status unverified

    MIL with P0351-P0355 and coil-on-plug damage

    2006–2008mkz, mkx, zephyr · NHTSA 10052190

    Same Ford bulletin as the Fusion and Edge entry; covers the Lincoln MKZ, MKX and 2006 Zephyr. The NHTSA summary does not give the repair steps.

    We couldn't confirm whether this bulletin is still current, so it doesn't count as confirmation.

  • P0356Ignition coil F primary or secondary circuit fault (the coil for cylinder 6 on most engines)

    Other bank Supported by vehicle data

    P0355 and P0356 are the cylinder 5 and 6 coil codes, and Ford TSB 18-2047 covers them together on 6.2L F-250 and F-350 trucks.

  • P0354Ignition coil D primary or secondary circuit fault

    Same system Supported by vehicle data

    Lexus LSB-0179-09 covers P0351 to P0356 together as the ignition coil primary and secondary circuit family.

All Ignition and engine position sensors codes

P0355 questions

Which cylinder is coil E?

On most engines it is cylinder 5, but the lettering depends on the engine. Check the service information for your vehicle before swapping parts.

Should I just replace the coil?

Swap it with another cylinder first. If the code follows the coil, the coil is bad. If not, check the connector, wiring and plug, and ask about bulletins.

Sources and review

  1. P0355 OBD Error Code: Ignition Coil E Primary/Secondary Circuit Malfunction — PartsAvatar
  2. Ford TSB 13-4-17: MIL with P0351-P0355 and coil-on-plug damage on 2006-2008 Fusion, Milan, Sable, Taurus, MKZ, MKX, Edge and 2006 Zephyr — Ford Motor Company / NHTSA
  3. 2001 Lincoln Continental Owner's Guide: Warning lights (Check engine) — Ford Motor Company
  4. Ford TSB 18-2047: MIL with P0355 and/or P0356 on 2014-2016 F-250/F-350 6.2L (open circuit in coil-on-plug connectors, cylinders 5 and 6) — Ford Motor Company / NHTSA
  5. Lexus LSB-0179-09: MIL with P0351-P0356 (ignition coil primary/secondary circuit) on ES 350 and RX 350 — Lexus / NHTSA
Last reviewed
Written by
Saurabh K.
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