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P0355 Code Explained: Ignition Coil “E” Primary/Secondary Circuit Malfunction Causes, Symptoms & Fixes

P0355 code illustration showing Ignition Coil "E", Cylinder 5 spark plug, ignition wiring, Check Engine Light, Pro Street TV logo, and www.ProStreetOnline.com.

If your OBD-II scanner displays P0355, your vehicle’s Engine Control Module (ECM) or Powertrain Control Module (PCM) has detected a malfunction in the Ignition Coil “E” Primary/Secondary Circuit.

The generic OBD-II definition for P0355 is:

Ignition Coil “E” Primary/Secondary Circuit Malfunction

On many vehicles, Ignition Coil “E” refers to the ignition coil serving Cylinder 5, although coil lettering can vary by manufacturer. The PCM continuously monitors the ignition coil circuit to verify that it receives proper voltage, ground, and switching commands.

When the PCM detects an open circuit, short circuit, abnormal current draw, missing control pulse, or improper coil response, it stores P0355 and illuminates the Check Engine Light.

The ignition system is responsible for:

Common causes include:

Because an ignition fault can produce severe misfires and catalytic converter damage, P0355 should be diagnosed and repaired promptly.

What Does the P0355 Code Mean?

The ignition coil converts battery voltage into the high voltage needed to create a spark inside the combustion chamber.

The PCM controls the coil’s primary circuit by rapidly switching it on and off. When the magnetic field inside the coil collapses, the secondary winding generates enough voltage to fire the spark plug.

If the PCM detects that the Ignition Coil “E” circuit is:

it stores P0355.

Unlike P0305, which indicates that Cylinder 5 is misfiring, P0355 specifically identifies an electrical malfunction affecting the Ignition Coil “E” circuit.

What Is an Ignition Coil?

Most modern engines use a Coil-on-Plug (COP) ignition system, where each cylinder has an individual ignition coil installed directly above the spark plug.

A typical ignition coil contains:

The coil converts approximately 12 volts into 20,000 to 60,000 volts, depending on engine design and operating conditions.

That voltage must be strong enough to jump the spark plug gap under cylinder compression.

Why Ignition Coil “E” Is Important

Ignition Coil “E” directly affects combustion in its assigned cylinder, commonly Cylinder 5.

Proper operation supports:

If the coil circuit fails, the affected cylinder may misfire intermittently or stop firing completely.

How the PCM Detects P0355

The PCM monitors several ignition-related values, including:

If the PCM commands Ignition Coil “E” but does not detect the expected response, it stores P0355.

On some vehicles, the PCM may disable fuel injection to the affected cylinder to protect the catalytic converter from unburned fuel.

What Does “Primary/Secondary Circuit Malfunction” Mean?

P0355 does not automatically mean the ignition coil itself has failed.

The code means a problem exists somewhere in the ignition coil’s electrical path.

The primary side includes:

The secondary side includes:

Possible causes include:

Proper testing is required before replacing parts.

Can a Bad Ignition Coil Cause P0355?

Absolutely.

A failed ignition coil is one of the most common causes of P0355.

Typical coil failures include:

A coil may operate normally at idle but fail under acceleration when spark demand increases.

Can a Bad Spark Plug Cause P0355?

Yes.

A worn or damaged spark plug may force the ignition coil to generate higher voltage than normal.

Common spark plug problems include:

The increased voltage demand may overheat the coil or expose weak insulation.

Replacing the coil while ignoring the worn plug is a fine way to buy the same part twice.

Can Wiring Problems Cause P0355?

Definitely.

Inspect the ignition coil circuit for:

Ignition wiring is exposed to heat, vibration, oil, and repeated service work, so harness damage is common.

Can Oil in the Spark Plug Well Cause P0355?

Yes.

Oil can enter the spark plug well through failed:

Oil contamination may damage:

The leak must be repaired before installing new ignition components.

Can Moisture Cause P0355?

Yes.

Moisture inside the spark plug well may cause:

This can occur after:

Can a PCM Problem Cause P0355?

Yes, but PCM failure is rare.

The PCM contains a driver circuit that controls the ignition coil.

A failed driver may cause:

The PCM should only be suspected after verifying:

The PCM is the final suspect, not the first part launched from the parts cannon.

P0355 Quick Facts

ItemInformation
DTCP0355
Generic DefinitionIgnition Coil “E” Primary/Secondary Circuit Malfunction
SystemIgnition / Engine Management
Typical Coil AssignmentCylinder 5 on many vehicles
SeverityHigh
Safe to Drive?Limited driving only
Common SymptomsCheck Engine Light, rough idle, misfire, hesitation, reduced power
Common CausesFailed coil, worn spark plug, wiring damage, connector problems
Typical Repair Cost$100–700+
Related CodesP0305, P0351, P0352, P0353, P0354, P0356

Common Symptoms of P0355

Drivers may experience:

Symptoms may be constant or intermittent depending on the failure.

Common Vehicles That Experience P0355

P0355 can appear on nearly any OBD-II vehicle using individual ignition coils, including:

It is especially common on:

What Does P0355 Really Mean?

Many drivers assume P0355 means:

“Replace the Cylinder 5 ignition coil.”

That may be correct, but the code actually means:

“The PCM detected an electrical malfunction in the Ignition Coil ‘E’ primary or secondary circuit. Inspect the coil, spark plug, connector, wiring, voltage supply, ground, and PCM control circuit before replacing parts.”

The underlying fault may involve:

A complete diagnosis should evaluate the entire circuit rather than assuming the coil is guilty because it was standing nearby.

Common P0355 Scan Tool Patterns

Using a professional scan tool is one of the fastest ways to diagnose P0355.

Because the PCM continuously monitors Ignition Coil “E,” live scan data can quickly determine whether the fault is caused by the ignition coil, spark plug, wiring, electrical connector, or PCM driver circuit.

Modern scan tools may display:

On many vehicles, Ignition Coil “E” corresponds to Cylinder 5, although the actual coil assignment should always be verified using factory service information.

Pattern 1: P0355 With Cylinder 5 Misfire

One of the most common scan-tool patterns is:

Possible causes include:

This is the most common real-world scenario associated with P0355.

Pattern 2: P0355 Without a Misfire Code

Some vehicles may display:

Possible causes include:

Early diagnosis often prevents larger ignition system failures.

Pattern 3: Misfire Only Under Load

Live data may show:

Possible causes include:

Many ignition coils pass every test at idle and immediately surrender once they’re asked to do actual work.

Pattern 4: Heat-Related Failure

Some ignition coils fail only after reaching operating temperature.

Symptoms include:

Possible causes include:

Heat cycling is one of the leading causes of ignition coil failure.

Pattern 5: Fuel Injector Disabled

Some PCM strategies disable fuel delivery to protect the catalytic converter.

Scan data may show:

Disabling fuel prevents raw gasoline from damaging the catalytic converter.

Pattern 6: Freeze-Frame During Heavy Acceleration

Freeze-frame data often shows:

These operating conditions place maximum electrical demand on the ignition coil.

Pattern 7: Multiple Ignition Codes

P0355 may appear with:

Multiple ignition circuit codes often indicate:

When several ignition coils report problems simultaneously, inspect the shared electrical circuits before replacing individual coils.

Common Symptoms of P0355

Symptoms vary depending on whether the failure is intermittent or complete.

Common symptoms include:

Some vehicles may continue driving relatively normally until ignition demand increases.

Check Engine Light

The Check Engine Light is typically the first symptom.

Companion codes commonly include:

A flashing Check Engine Light indicates an active catalyst-damaging misfire.

Rough Idle

A failed Ignition Coil “E” often causes:

The idle may improve slightly as engine speed increases.

Engine Misfire

Without sufficient spark energy, Cylinder 5 cannot consistently ignite the air/fuel mixture.

Drivers may notice:

Persistent misfires should never be ignored.

Loss of Power

When Cylinder 5 stops contributing power:

The PCM may also activate a reduced-power strategy.

Poor Fuel Economy

A cylinder that misfires wastes fuel.

Drivers may experience:

Fuel economy often drops significantly until repairs are completed.

Strong Fuel Odor

A failed ignition event allows raw fuel into the exhaust.

Possible symptoms include:

This should be repaired immediately to prevent catalyst damage.

Is P0355 Serious?

Yes. P0355 is considered a high-severity diagnostic trouble code.

Ignoring the problem may lead to:

Prompt diagnosis is strongly recommended.

Can You Drive With P0355?

Limited driving may be possible, but it is not recommended.

Avoid driving if you experience:

Driving with a persistent ignition failure often turns an inexpensive coil replacement into an expensive catalytic converter replacement.

P0355 vs Related Trouble Codes

Understanding related ignition system codes simplifies diagnosis.

P0355

Ignition Coil “E” Primary/Secondary Circuit Malfunction

Electrical fault affecting Ignition Coil “E.”

P0305

Cylinder 5 Misfire Detected

The PCM detects combustion failure on Cylinder 5.

P0351

Ignition Coil “A” Primary/Secondary Circuit Malfunction

Electrical fault affecting Ignition Coil “A.”

P0352

Ignition Coil “B” Primary/Secondary Circuit Malfunction

Electrical fault affecting Ignition Coil “B.”

P0353

Ignition Coil “C” Primary/Secondary Circuit Malfunction

Electrical fault affecting Ignition Coil “C.”

P0354

Ignition Coil “D” Primary/Secondary Circuit Malfunction

Electrical fault affecting Ignition Coil “D.”

P0356

Ignition Coil “F” Primary/Secondary Circuit Malfunction

Electrical fault affecting Ignition Coil “F.”

30 Common Causes of P0355

The most common causes include:

  1. Failed Ignition Coil “E”
  2. Internal coil winding failure
  3. Excessive spark plug gap
  4. Worn spark plug
  5. Fouled spark plug
  6. Oil-contaminated spark plug
  7. Cracked ignition coil housing
  8. Damaged coil boot
  9. Carbon tracking
  10. Moisture intrusion
  11. Open ignition coil circuit
  12. Shorted ignition coil circuit
  13. Broken wiring
  14. Chafed wiring harness
  15. Loose electrical connector
  16. Corroded terminals
  17. Oil in the spark plug well
  18. Coolant contamination
  19. Poor engine ground
  20. Weak battery voltage
  21. Charging system problems
  22. PCM driver circuit failure
  23. Incorrect spark plug
  24. Low-quality aftermarket ignition coil
  25. Engine overheating
  26. Rodent-damaged wiring
  27. Water intrusion after engine washing
  28. Poor previous wiring repairs
  29. PCM connector damage
  30. Failed PCM (rare)

Final Thoughts

The P0355 Ignition Coil “E” Primary/Secondary Circuit Malfunction code indicates the PCM has detected an electrical problem affecting Ignition Coil “E,” commonly associated with Cylinder 5.

Although the ignition coil itself is often responsible, the fault may also involve:

Proper diagnosis should identify the exact failure before replacing components.

The next section covers:

Following a structured diagnostic process helps restore proper ignition performance while preventing unnecessary parts replacement and catalytic converter damage.

Related Pro Street Diagnostic Guides

How to Diagnose the P0355 Code

Diagnosing P0355 requires determining why the Powertrain Control Module (PCM) has detected a malfunction in the Ignition Coil “E” Primary/Secondary Circuit.

Unlike P0305, which identifies a combustion misfire on Cylinder 5, P0355 is an electrical circuit code. The fault may involve the ignition coil, spark plug, wiring, connector, voltage supply, ground circuit, or PCM driver.

The most common causes include:

Because prolonged misfires can damage the catalytic converter, diagnosis should begin as soon as possible.

Safety Precautions

Before beginning diagnosis:

Modern ignition coils may produce 20,000 to 60,000 volts. Never disconnect ignition components while the engine is running.

Tools Required

Professional diagnosis may require:

A dedicated spark tester provides far more accurate results than trying to improvise with a loose spark plug.

Step 1 – Verify the Code

Connect a professional scan tool.

Record:

Monitor:

Always save freeze-frame data before clearing any codes.

Step 2 – Check for Related Trouble Codes

P0355 commonly appears with:

Related codes help determine whether the fault affects only one ignition coil or multiple cylinders.

Code CombinationLikely Diagnosis
P0355 onlyIgnition Coil “E” circuit fault
P0355 + P0305Coil, spark plug, or wiring fault on Cylinder 5
P0355 + multiple P035X codesShared wiring, power supply, or PCM issue
P0355 + P0363Severe misfire with fuel disabled

Step 3 – Confirm Coil Assignment

Before replacing any components, verify which cylinder corresponds to Ignition Coil “E.”

On many engines, Coil “E” controls Cylinder 5, but manufacturer assignments vary.

Confirm using:

Never assume coil lettering always matches firing order.

Step 4 – Review Freeze-Frame Data

Review:

Determine whether the failure occurred:

This information frequently identifies intermittent ignition failures.

Step 5 – Perform a Visual Inspection

Inspect Ignition Coil “E.”

Look for:

Many ignition coil failures can be identified during a careful visual inspection.

Step 6 – Inspect the Wiring Harness

Trace the ignition coil wiring harness.

Inspect for:

Repair damaged wiring before replacing ignition components.

Step 7 – Inspect the Electrical Connector

Disconnect the ignition coil connector.

Inspect for:

Connector failures are among the most common causes of P0355.

Step 8 – Verify Battery and Charging System Voltage

Low system voltage can interfere with ignition coil performance.

Normal readings:

Repair charging system faults before continuing diagnosis.

Step 9 – Monitor Cylinder 5 Misfire Data

Using a professional scan tool, monitor:

Rapidly increasing Cylinder 5 misfire counts usually indicate an ignition system problem.

Step 10 – Perform an Ignition Coil Swap Test

Move Ignition Coil “E” to another cylinder.

For example:

If the fault moves:

the ignition coil is defective.

If P0355 remains assigned to the original circuit, suspect wiring, connector, power supply, or PCM control issues.

Step 11 – Inspect the Spark Plug

Remove the Cylinder 5 spark plug.

Inspect for:

A worn spark plug places additional stress on the ignition coil and may contribute to repeat failures.

Step 12 – Test Spark Output

Use an adjustable spark tester.

Verify:

Weak spark supports an ignition coil, wiring, voltage supply, or PCM control problem.

Step 13 – Verify Coil Power Supply

Using a multimeter:

Verify:

If voltage is missing, inspect:

Multiple ignition coil codes often indicate a shared power supply problem.

Step 14 – Verify Ground Integrity

Inspect:

Verify:

Poor grounds can create intermittent ignition coil circuit faults.

Step 15 – Test the PCM Control Signal

Using an oscilloscope or logic probe:

Verify:

A missing PCM control signal may indicate:

PCM failure should only be considered after every other component has passed inspection.

Step 16 – Test Ignition Coil Resistance

Where applicable, compare:

to manufacturer specifications.

Many modern smart coils contain internal electronics, making waveform analysis and swap testing more accurate than resistance testing alone.

Step 17 – Inspect for Oil or Coolant Contamination

Inspect the spark plug well for:

Common sources include:

Repair all leaks before installing replacement ignition components.

Step 18 – Check Cylinder Compression (If Necessary)

If all ignition system tests pass but Cylinder 5 continues to misfire:

Perform:

Possible mechanical faults include:

Mechanical failures usually trigger P0305, but multiple faults may exist simultaneously.

Step 19 – Review Technical Service Bulletins

Check manufacturer Technical Service Bulletins (TSBs) for:

Factory bulletins often identify known vehicle-specific failures.

Step 20 – Confirm the Diagnosis

Before replacing expensive components, verify:

Completing these diagnostic procedures accurately identifies the root cause of P0355 while preventing unnecessary parts replacement.

Step 21 – Replace the Ignition Coil

If testing confirms Ignition Coil “E” has failed, replacement is the proper repair.

Common signs of ignition coil failure include:

General replacement procedure:

  1. Disconnect the negative battery cable.
  2. Remove any engine covers.
  3. Disconnect the ignition coil electrical connector.
  4. Remove the ignition coil retaining bolt.
  5. Carefully pull the ignition coil straight upward.
  6. Inspect the spark plug well for oil, coolant, or moisture.
  7. Install a new OEM-quality ignition coil.
  8. Apply dielectric grease to the coil boot if recommended.
  9. Reconnect the electrical connector.
  10. Clear all diagnostic trouble codes.

Using OEM or premium aftermarket ignition coils provides the best reliability and helps prevent repeat failures.

Step 22 – Replace the Spark Plug

A worn spark plug often contributes to ignition coil failure.

Inspect the spark plug for:

Replace spark plugs according to manufacturer specifications.

If the spark plug has excessive wear, replacing only the ignition coil may result in another failure shortly afterward.

Step 23 – Repair Wiring Problems

Inspect the complete ignition coil wiring harness.

Look for:

Repair damaged wiring using:

Many intermittent P0355 faults are caused by damaged wiring rather than the ignition coil itself.

Step 24 – Repair or Replace Electrical Connectors

Inspect the ignition coil connector for:

Replace damaged connectors using OEM repair kits whenever possible.

A loose connector can produce the same symptoms as a failed ignition coil.

Step 25 – Repair Oil or Coolant Leaks

Contamination inside the spark plug well dramatically shortens ignition coil life.

Inspect for:

Repair all leaks before installing replacement ignition components.

Ignoring the leak almost guarantees another ignition coil failure.

Step 26 – Repair Engine Ground Problems

Inspect all ignition-related grounds.

Verify:

Poor grounding can create:

Clean and tighten all ground connections before condemning expensive components.

Step 27 – Repair the PCM Driver Circuit (If Necessary)

If testing confirms the ignition coil, spark plug, wiring, connectors, voltage supply, and grounds are functioning correctly:

Inspect:

PCM driver failures are uncommon and should only be considered after eliminating every other possible cause.

Step 28 – Update PCM Software

Before replacing the PCM:

Review manufacturer Technical Service Bulletins (TSBs).

Manufacturers occasionally release software updates correcting:

Always install the latest PCM calibration when applicable.

Step 29 – Complete an OBD-II Drive Cycle

After repairs:

Confirm that P0355 does not return.

Step 30 – Verify the Repair

After repairs:

  1. Clear all diagnostic trouble codes.
  2. Start the engine.
  3. Verify a smooth idle.
  4. Road test the vehicle.
  5. Monitor Cylinder 5 misfire counters.
  6. Verify stable ignition timing.
  7. Confirm no pending or permanent DTCs return.
  8. Ensure the Check Engine Light remains off.

A successful repair restores full engine performance, smooth operation, proper fuel economy, and reliable ignition system function.

How to Fix P0355

The proper repair depends entirely on the diagnostic results.

Common repairs include:

Never replace the PCM until every ignition component and electrical circuit has been thoroughly tested.

Typical Repair Costs

RepairTypical Cost
Professional diagnosis$100–250
Ignition coil replacement$125–350
Spark plug replacement$150–450
Ignition coil connector replacement$100–250
Wiring repair$100–350
Valve cover gasket replacement$200–600
Spark plug tube seal replacement$250–700
Engine ground repair$75–200
PCM software update$100–250
PCM replacement (rare)$800–2,000+

Repair costs vary depending on labor rates, engine configuration, and component accessibility.

Common Diagnostic Mistakes

Avoid these common mistakes:

Many P0355 repairs involve spark plugs, wiring, or connector problems—not PCM failure.

Manufacturer-Specific Notes

General Motors (Chevrolet, GMC, Cadillac, Buick)

Inspect:

Heat exposure is a common cause of ignition coil failure on high-mileage GM engines.

Ford/Lincoln

Inspect:

Many Ford engines experience intermittent ignition failures that become noticeable under heavy acceleration.

Chrysler, Dodge, Jeep, Ram

Inspect:

Heat-related wiring damage is a common failure point.

Toyota/Lexus

Inspect:

Oil contamination frequently causes repeat ignition coil failures.

Nissan/Infiniti

Inspect:

Several Nissan V6 engines develop ignition coil failures after repeated heat cycling.

Honda/Acura

Inspect:

OEM ignition components generally provide the most reliable long-term repair.

Frequently Asked Questions

What usually fixes P0355?

The most common repairs include replacing a failed ignition coil, replacing worn spark plugs, repairing damaged wiring, replacing faulty electrical connectors, repairing oil leaks into the spark plug wells, or correcting poor engine ground connections.

Can I drive with P0355?

Limited driving may be possible, but repairs should be completed immediately. Driving with an active ignition fault can lead to catalytic converter damage, poor engine performance, increased fuel consumption, and additional ignition system failures.

Does P0355 always mean the ignition coil is bad?

No. While the ignition coil is the most common cause, P0355 may also result from damaged wiring, faulty connectors, worn spark plugs, oil contamination, poor ground connections, or a failed PCM driver circuit.

Can a bad spark plug cause P0355?

Yes. A worn or improperly gapped spark plug increases ignition voltage demand, placing additional stress on the ignition coil and potentially triggering P0355.

Is P0355 a serious code?

Yes. P0355 is considered a high-severity diagnostic trouble code. Ignoring it can result in severe engine misfires, catalytic converter damage, reduced fuel economy, increased emissions, and poor engine performance.

Final Thoughts

The P0355 Ignition Coil “E” Primary/Secondary Circuit Malfunction code indicates the PCM has detected an electrical fault affecting the ignition system. While a failed ignition coil is the most common cause, the root problem may also involve worn spark plugs, damaged wiring, poor electrical connections, oil contamination, valve cover leaks, or PCM driver issues.

Fortunately, ignition coil failures, spark plug wear, damaged connectors, wiring faults, and oil contamination account for the overwhelming majority of P0355 repairs.

A complete diagnosis should always verify:

Following a structured diagnostic process prevents unnecessary parts replacement while restoring reliable ignition performance, smooth engine operation, maximum fuel economy, and long-term engine reliability.

Continue Your Pro Street Ignition System Series

Related guides include:

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