P0355 on 2007-2012 Hyundai Santa Fe 3.3L: Ignition Coil 'E' Circuit Causes and Fixes

What's Unique About the 2007-2012 Hyundai Santa Fe

The critical issue for a P0355 code on this Santa Fe is the location of cylinder #5. The 3.3L V6 engine is mounted transversely, placing cylinders 1, 3, and 5 in the rear bank against the firewall, hidden beneath the upper intake manifold. Unlike the easily accessible front coils (cylinders 2, 4, 6), replacing the coil for cylinder #5 is a labor-intensive job that requires removing the entire intake plenum. This significantly increases the complexity and cost of the repair compared to the same code on an engine with easier coil access.

Symptoms You May Notice

• Check Engine Light is on (solid or flashing)
• Rough idle and engine vibration
• Noticeable loss of power and sluggish acceleration
• Engine hesitation or stumbling
• Potential for engine stalling
• Possible fuel smell from the exhaust

Most Likely Causes

1. Failed Ignition Coil (Cylinder #5) 🔴 High Probability → Shop Ignition Coil Ignition coils are a common wear item that fail from constant exposure to high engine temperatures and vibration over many miles. The rear bank coils may be more susceptible to failure due to reduced airflow and higher ambient temperatures near the firewall.
   How to confirm: Because cylinder #5 is under the intake manifold, a simple coil swap for diagnosis is impractical. The most logical approach is to assume the coil is bad once the manifold is removed for access. At that point, replacement is the standard procedure. A professional with a Hyundai GDS scan tool could theoretically command the coil to fire, but this is rarely done.
   Typical fix: Replace the ignition coil for cylinder #5. 🎬 See how to replace the ignition coils on a 3.3L It is highly recommended to replace all three rear coils (cylinders 1, 3, 5), all six spark plugs, and the upper intake manifold gaskets at the same time to avoid repeating the labor-intensive disassembly.
   Est. part cost: $40-$90 for one aftermarket coil, $100-$160 for one OEM coil.
2. Worn or Fouled Spark Plugs 🟡 Medium Probability → Shop Spark Plug Spark plugs are a standard maintenance item with a service life of around 100,000 miles. An old plug with a large electrode gap requires more voltage to fire, which puts excessive strain on the ignition coil, leading to overheating and premature failure.
   How to confirm: Once the intake manifold and ignition coil are removed, inspect the spark plug for cylinder #5. Look for a cracked insulator, heavy carbon deposits, oil fouling, or a severely worn electrode.
   Typical fix: Replace all six spark plugs. 🎬 Watch: Step-by-step spark plug replacement on this V6 engine This should always be done when replacing the rear ignition coils as a preventative measure to protect the new parts.
   Est. part cost: $8-$25 per spark plug, depending on brand (OEM or aftermarket).
3. Leaking Valve Cover Gasket ⚪ Low Probability → Shop Engine Valve Cover The valve cover gaskets on the 3.3L Lambda V6 are known to become hard and brittle over time, allowing engine oil to leak into the spark plug tubes. This is a well-documented issue on this platform.
   How to confirm: When the ignition coil is removed from cylinder #5, visually inspect the spark plug tube for pooled engine oil. The presence of oil confirms the valve cover gasket and its integrated tube seals are leaking.
   Typical fix: Replace the rear valve cover gasket and the spark plug tube seals. This must be done to prevent the new ignition coil from being damaged by oil saturation. The oil-soaked coil boot should also be thoroughly cleaned or replaced.
   Est. part cost: $30-$70 for a valve cover gasket set.
4. Damaged Wiring or Connector ⚪ Low Probability The plastic connector for the ignition coil can become brittle from years of heat cycles and crack, especially the locking tab. The wiring itself can also be damaged by rodents or chafing, leading to a poor connection.
   How to confirm: After removing the intake manifold, carefully inspect the ignition coil connector and wiring for cylinder #5. Check for cracks, corrosion, loose pins, or signs of rodent damage.
   Typical fix: Repair the damaged section of the wiring harness or replace the connector pigtail.
   Est. part cost: $10-$30 for a new connector pigtail.

Rare But Worth Checking

• Faulty Powertrain Control Module (PCM): → Shop Engine Control Module (ECM) This is extremely rare. The internal driver circuit in the PCM that controls the ignition coil can fail, but this should only be considered after all other possibilities (coil, plug, wiring) have been exhaustively ruled out by a professional.

Diagnosis Steps

1. Confirm the presence of the P0355 code using an OBD-II scanner.
2. Note any other accompanying codes, such as P0305 or P0300.
3. Verify the cylinder layout: The rear bank (against the firewall) contains cylinders 1, 3, and 5, from passenger side to driver's side. The front bank (near the radiator) contains 2, 4, and 6.
4. Disconnect the negative battery terminal.
5. Carefully remove the upper intake manifold plenum. This involves disconnecting the air intake hose, throttle body, various vacuum hoses (PCV, brake booster), and electrical connectors. Label everything with masking tape and a marker to ensure proper reassembly.
6. Once the manifold is removed, you will have access to the three rear ignition coils. Cylinder 5 is the one closest to the driver's side on the rear bank.
7. Remove the 10mm bolt holding the cylinder #5 ignition coil and pull the coil out.
8. Inspect the spark plug tube for any pooled oil, which would indicate a leaking valve cover gasket.
9. At this stage, it is highly recommended to replace all three rear ignition coils, all six spark plugs, and the intake manifold gaskets.
10. If oil was present in the spark plug tube, the rear valve cover gasket must also be replaced. This involves removing the valve cover itself.
11. Carefully reassemble all components. Ensure all connectors and hoses are reattached. Torque the intake manifold bolts to factory specifications (typically in a specific sequence, starting from the center and working outwards) to prevent vacuum leaks.
12. Reconnect the battery, clear the codes with the scanner, and start the engine to verify the repair.

Parts You'll Likely Need

• Ignition Coil (OEM #27301-3C000) — This is the most common cause of a P0355 code. The original coils fail due to age and heat cycles. The OEM part number 27301-3C000 may be superseded by 27301-3C010.
  Trusted brands: Hyundai (OEM), NGK, Delphi, Denso
  OEM price range: $100-$160
  Aftermarket price range: $40-$90
• Spark Plug (OEM #NGK IFR5G-11) — Worn spark plugs strain the ignition coils and are a critical maintenance item that should be replaced when accessing the rear bank.
  Trusted brands: NGK, Denso
  OEM price range: $15-$25
  Aftermarket price range: $8-$15
• Upper Intake Manifold Gasket Set (OEM #29215-3C000 (Plenum Gasket)) — These are single-use gaskets that must be replaced anytime the intake manifold is removed to prevent vacuum leaks. An aftermarket example is Fel-Pro MS 96464.
  Trusted brands: Hyundai (OEM), Fel-Pro, Mahle
  OEM price range: $25-$40
  Aftermarket price range: $15-$30
• Rear Valve Cover Gasket (OEM #22441-3C110) — Only needed if oil is found in the spark plug tubes. This part often comes in a kit that includes the spark plug tube seals.
  Trusted brands: Hyundai (OEM), Fel-Pro, Victor Reinz
  OEM price range: $40-$60
  Aftermarket price range: $25-$45

Related Codes That Often Appear With This One

• P0305 — P0305 means 'Cylinder 5 Misfire Detected.' A P0355 fault directly prevents the spark plug from firing correctly, which is the most common cause of a misfire on that cylinder. These two codes almost always appear together.
• P0300 — This code for 'Random/Multiple Cylinder Misfire' can appear if the P0355 fault is intermittent or if other cylinders are also having ignition problems due to failing coils or plugs.
• P0351, P0353 — These are the ignition coil circuit codes for cylinders 1 and 3, which are the other two coils on the difficult-to-access rear bank. Seeing them together with P0355 strongly suggests a widespread failure of the rear coils and reinforces the recommendation to replace all three at once.

Platform-Specific Known Issues

• The primary issue is the labor-intensive process required to access the rear bank of cylinders (1, 3, 5), which necessitates the removal of the upper intake manifold. This turns a simple ignition coil replacement into a multi-hour job.

Mechanic-Grade Diagnostic Values

• Ignition Coil Primary Winding Resistance — expected: 0.62 Ω ± 10% at 20°C (68°F). Failure: A reading of infinity (open circuit) or near zero (short circuit) confirms a failed primary winding.
• Ignition Coil Secondary Winding Resistance — expected: 7.0 kΩ ± 15% at 20°C (68°F). Failure: A reading significantly outside this range indicates a failure in the secondary winding.
• Ignition Coil Connector Power Supply Pin — expected: Battery Voltage (~12V) with Key On, Engine Off.. Failure: A reading of 0V points to a problem in the power supply circuit, such as the ignition coil fuse or wiring from the main relay.
• PCM Driver Signal at Coil Connector — expected: A pulsing ground signal, best observed as a square wave on an oscilloscope or a fluctuating frequency (5-20 Hz) on a graphing multimeter while the engine is running.. Failure: A constant ground, constant voltage, or no signal indicates a break in the signal wire to the PCM or a failed PCM driver circuit.

Scan Tool Commands That Help

• Hyundai GDS (Global Diagnostic System): Actuation Test > Ignition Coil — This function allows a technician to command the PCM to fire a specific ignition coil. While impractical for cylinder #5 before disassembly, it can be used to verify the PCM driver and wiring integrity if a new coil and plug do not resolve the issue. It's also useful for testing the old coil on a bench after removal.
• Hyundai GDS (Global Diagnostic System): Vehicle S/W Management > Resetting Adaptive Values — After a major repair like replacing coils, plugs, and gaskets, it's good practice to reset the engine's adaptive learning values. This forces the PCM to relearn fuel trims and idle strategy with the new, correctly functioning components.

Wiring & Ground Locations

• G52 — Located in the left rear of the engine compartment, often near the PCM or strut tower.. This is a primary engine control ground. A loose or corroded G52 ground can cause a host of intermittent electrical issues, including weak or erratic ignition coil performance that could potentially trigger a P0355 code.
• Cylinder #5 Ignition Coil Connector — On the rear valve cover, driver's side, underneath the upper intake manifold.. This 3-pin connector provides power, ground, and the trigger signal from the PCM to the coil. Pin 1 is typically the PCM trigger (ground pulse), Pin 2 is the main ground, and Pin 3 is the 12V+ power supply from the ignition relay.

OEM Part Supersession History

• 27301-3C010 → 27301-3C000 — Standard manufacturer part revision and update. The parts are interchangeable.

Diagnostic Flowchart

Other Known Issues on This Vehicle

Issues unrelated to this code that are worth knowing about as an owner of this generation:

• Faulty Fuel Level Sending Unit 🟠 Medium — Very common on 2007-2009 models, causing inaccurate fuel gauge readings.
• Leaking Valve Cover Gaskets 🟠 Medium → Shop Engine Valve Cover — Common failure item. The front gasket can leak oil onto the alternator, causing it to fail. The rear gasket leak can cause this P0355 code.
• Leaking Oil Pressure Sensor/Switch 🟡 Low — The sensor on V6 models is prone to developing oil leaks over time.
• Prematurely Worn Suspension Components 🟠 Medium — Ball joints, tie rods, and control arm bushings can wear out relatively quickly, leading to noise and alignment issues.
• Crankshaft Position Sensor Failure 🔴 High — A known issue that can cause the engine to stall or fail to start.

Used vs. New Parts: Buying Guide for This Vehicle

When a used part is the smart pick: For this specific repair, using used parts is generally not recommended for the core components. The high labor cost of accessing the rear bank means you should use new, reliable parts to ensure the job only has to be done once. A used intake manifold or engine cover is acceptable if the original was damaged during removal.

Donor-vehicle mileage cap: roughly under 80000 miles for the part to have meaningful remaining life.

What to inspect on the donor part:

• For any considered used part, check for a vehicle history report to avoid parts from flood or major accident vehicles.
• Inspect plastic components like connectors and vacuum nipples for brittleness or cracks.
• If considering a used coil, check the boot for any signs of oil saturation, which indicates it was exposed to a valve cover leak and may have a shortened life.

OEM-only on this vehicle (don't cheap out):

• Intake Manifold Gaskets: These are single-use crush gaskets. Never reuse them. While quality aftermarket gaskets from brands like Fel-Pro are acceptable, OEM is a safe bet.

Aftermarket brands forum-validated for this vehicle:

• Ignition Coils: Denso, Delphi, NGK
• Spark Plugs: NGK, Denso (use the specific Iridium plug recommended for the vehicle)
• Gaskets: Fel-Pro, Mahle, Victor Reinz

Brands owners have reported issues with on this vehicle:

• Unbranded, no-name ignition coils from online marketplaces. These often have high failure rates and may not meet the required voltage specifications, leading to repeat failures and potential damage to the PCM.

Real Owner Stories

Aggregated from forums and TSBs cited above. Mileages and costs reflect what owners reported in those sources.

Related OBD-II Codes

• P0305 — Cylinder 5 Misfire Detected — this code often accompanies P0355 when the ignition coil for cylinder 5 fails to fire the spark plug.
• P0300 — Random or Multiple Cylinder Misfire Detected — may be triggered alongside P0355 if the ignition failure causes instability across the engine bank.
• P0351 — Ignition Coil 'A' Primary/Secondary Circuit — relates to cylinder #1, which is also located on the hard-to-access rear bank of the 3.3L engine.
• P0353 — Ignition Coil 'C' Primary/Secondary Circuit — relates to cylinder #3, the middle cylinder on the rear bank that shares the same labor-intensive access requirements as cylinder #5.

Frequently Asked Questions