P0355 on 2012-2018 Jeep Wrangler 3.6L: Ignition Coil 'E' Circuit Malfunction Causes and Fixes

What's Unique About the 2012-2018 Jeep Wrangler

The 2012-2018 Jeep Wrangler uses the reliable 3.6L Pentastar V6 engine, which is found in many Chrysler, Dodge, and Jeep vehicles. For this engine, code P0355 points specifically to cylinder #5, which is the rearmost cylinder on the passenger (right) side of the engine, closest to the firewall. A key challenge for this repair is that accessing any of the passenger-side coils (1, 3, 5) requires removing the upper intake manifold. This turns a simple coil swap into a more involved job, requiring new intake gaskets and adding an hour or more to the repair time.

Generation note: The 2012-2018 model years all fall within the Jeep Wrangler JK generation. The 3.6L Pentastar V6 engine was introduced to the Wrangler in 2012 and was used until the end of the JK generation in 2018. Therefore, the information in this guide is consistent across this entire year range.

Symptoms You May Notice

• Check Engine Light is on or flashing
• Rough or shaky idle
• Engine misfire, which may feel like a stumble or hesitation on acceleration
• Reduced engine power and poor acceleration
• Decreased fuel economy

Most Likely Causes

1. Faulty Ignition Coil 🔴 High Probability Ignition coils are a common wear item that can fail from constant heat cycles and vibration over time. The coils on the passenger side bank, under the intake manifold, may be exposed to more trapped heat, potentially accelerating degradation.
   How to confirm: The easiest way to confirm a bad coil is to swap the ignition coil from cylinder #5 with another cylinder on the same bank (e.g., cylinder #3). Clear the codes and drive the vehicle. If the code changes to P0353 (for cylinder #3), the coil is faulty and needs to be replaced. This test definitively isolates the coil as the problem.
   Typical fix: Replace the ignition coil for cylinder #5. Due to the labor involved in removing the intake manifold, many owners and shops elect to replace all three coils (1, 3, 5) and all six spark plugs at the same time as preventative maintenance.
   Est. part cost: $40-$90
2. Worn or Fouled Spark Plug 🟡 Medium Probability Spark plugs have a finite service life, recommended at 100,000 miles for this engine. A worn electrode or excessive carbon fouling increases the electrical resistance, which can overload the ignition coil's secondary circuit and cause it to fail, triggering the P0355 code.
   How to confirm: Remove the spark plug from cylinder #5 and inspect it for wear (rounded electrode), damage (cracked porcelain), or fouling (black, sooty, or oily deposits). Compare it to a new spark plug. If the plug is original and the vehicle is near or over 100,000 miles, it is due for replacement regardless of appearance.
   Typical fix: Replace the spark plug in cylinder #5. It is highly recommended to replace all six spark plugs at the same time for balanced engine performance, especially since the intake manifold must be removed to access three of them.
   Est. part cost: $15-$30 per plug
3. Damaged Wiring or Loose Connector ⚪ Low Probability The plastic locking tab on the ignition coil's electrical connector can become brittle from engine heat and break, leading to a poor or intermittent connection that mimics a coil failure. The wiring harness can also be damaged from abrasion against other engine components.
   How to confirm: Visually inspect the wiring harness and connector for cylinder #5's ignition coil. Look for any signs of chafing, melting, corrosion, or broken wires. Wiggle the connector while the engine is idling (if possible) to see if it affects the misfire. Ensure the connector is securely plugged into the coil and that the locking tab is intact.
   Typical fix: If the connector is damaged, it may need to be replaced with a new pigtail connector (Mopar p/n 68064983AA). This requires cutting the old connector off and splicing the new one in. 🎬 Watch: How to diagnose and fix ignition coil circuit codes If the wiring is damaged, the affected section will need to be repaired.
   Est. part cost: $15-$40 for a pigtail connector

Rare But Worth Checking

• Faulty Powertrain Control Module (PCM): While rare, the internal driver circuit in the PCM that controls the ignition coil can fail. This should only be considered after all other possibilities (coil, plug, wiring) have been thoroughly ruled out. A PCM failure can sometimes damage the new coil instantly upon installation, so proper diagnosis is critical.
• Oil leak into spark plug tube: The 3.6L Pentastar can develop oil leaks from the valve cover gaskets or spark plug tube seals. If oil is found pooling in the spark plug well when removing the ignition coil, the leaking gasket must be replaced. This oil can saturate the coil boot and cause a short or misfire, leading to premature failure of the new coil.

Diagnosis Steps

1. Retrieve all stored trouble codes with an OBD-II scanner.
2. Confirm that P0355 and likely P0305 are present.
3. Locate cylinder #5, which is the rear-most cylinder on the passenger side of the engine. The passenger bank is cylinders 1-3-5 (front to back); the driver's side is 2-4-6.
4. To access the ignition coils on the passenger side, the upper intake manifold must be removed. This involves disconnecting the battery, various sensors, and vacuum lines.
🎬 See how to remove the upper intake manifold
5. Once the manifold is off, inspect the wiring and electrical connector for the cylinder #5 ignition coil for any signs of damage, corrosion, or a loose connection.
6. If the wiring looks good, swap the ignition coil from cylinder #5 with the coil from another cylinder (e.g., cylinder #3, the middle cylinder on the passenger side).
7. Temporarily reinstall the intake manifold, clear the codes, and start the engine. Let it run and then re-scan for codes.
8. If the code has moved to the cylinder where the coil was moved (e.g., P0353), the ignition coil is faulty and should be replaced.
9. If the P0355 code returns, the problem is likely with the spark plug, wiring, or the PCM. Remove and inspect the spark plug for cylinder #5.
10. If the spark plug is worn or fouled, replace it. It's best practice to replace all six.
11. If the plug is fine, perform a continuity test on the wiring between the PCM and the coil connector to check for opens or shorts. Check for 12V power and a pulsing ground signal at the connector with the engine cranking.
12. If wiring, coil, and plug are all confirmed to be good, the issue may be with the PCM, which requires professional diagnosis.

Parts You'll Likely Need

• Ignition Coil (OEM #5149168AJ) — This is the most frequent cause of a P0355 code due to being a common wear-and-tear component. The original part number 5149168AI has been superseded by 5149168AJ.
  Trusted brands: Mopar, NGK, Denso, Bosch
  OEM price range: $75-$100
  Aftermarket price range: $40-$70
• Iridium Spark Plug (OEM #SP149125AF) — A worn or fouled spark plug can cause the ignition coil to fail and is often replaced at the same time as the coil as good preventative maintenance.
  Trusted brands: Mopar, NGK, Champion, Bosch
  OEM price range: $25-$35
  Aftermarket price range: $15-$25
• Upper and Lower Intake Manifold Gaskets (OEM #5184562AC, 5184331AC) — These gaskets are considered single-use and must be replaced whenever the intake manifold is removed to prevent vacuum leaks.
  Trusted brands: Mopar, Fel-Pro, Mahle
  OEM price range: $30-$50 for the set
  Aftermarket price range: $15-$30 for the set

Related Codes That Often Appear With This One

• P0305 — P0305 means "Cylinder 5 Misfire Detected." Since P0355 indicates an electrical fault in the ignition circuit for cylinder 5, a misfire on that cylinder is a direct and expected symptom. A P0355 code will almost always be accompanied by a P0305.

Platform-Specific Known Issues

• Access to the passenger-side ignition coils (including cylinder #5) is blocked by the upper intake manifold. Removal is required for diagnosis and repair, adding complexity and time to the job. This is a good opportunity to replace all three coils and spark plugs on that bank, as well as the intake gaskets.

Mechanic-Grade Diagnostic Values

• Ignition Coil Primary Winding Resistance — expected: 0.4 to 0.8 ohms. Failure: A reading of 0 ohms (short) or infinite/OL (open circuit).
• Ignition Coil Secondary Winding Resistance — expected: 6,000 to 11,000 ohms (6kΩ to 11kΩ). Failure: A reading significantly outside this range, or OL (open circuit), indicates a faulty coil.
• Voltage at Coil Connector Power Wire — expected: 12V (Battery Voltage) with key on, engine off.. Failure: A reading of 0V points to a blown fuse or a break in the power supply wire.

Wiring & Ground Locations

• G101 and G104 — On the back of the engine, under a heat shield near the catalytic converter on the passenger (right) side.. These are main engine grounds. A poor connection here can cause a host of electrical issues, including erratic behavior in the ignition system that could potentially trigger a circuit code like P0355.
• G103 and G105 — On the passenger (right) side of the engine bay, on the fender.. These are primary chassis grounds. A corroded or loose connection at these points can affect the stability of the entire vehicle electrical system, impacting sensor and actuator performance.
• Ignition Coil Connector Pinout — The electrical connector on top of the ignition coil for cylinder #5.. When diagnosing, you must test for 12V power on the supply wire and a pulsing ground signal from the PCM on the control wire. A wiring diagram is needed to identify the specific pins for these tests.

OEM Part Supersession History

• 5149168AH, 5149168AI → 5149168AJ — Standard part revision and improvement by the manufacturer.

Model Year Variations Within This Range

• 2016-2018: For the 2016 model year, the 3.6L Pentastar engine was updated. This 'Pentastar Upgrade' included new ignition coils as part of a broader set of changes to improve efficiency and power. While the coils are physically interchangeable, it's best practice to use parts specified for the correct year range.

Diagnostic Flowchart

Other Known Issues on This Vehicle

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

• Cracked Oil Filter / Cooler Housing 🔴 High — Extremely common, often occurs between 60,000-120,000 miles. The plastic housing cracks from heat cycles, causing major oil and/or coolant leaks into the engine valley. (Ref: TSB 09-008-22 addresses unnecessary replacement but acknowledges leak issues.)
• Rocker Arm / Lifter Failure ('Pentastar Tick') 🔴 High — Common across all years, but especially noted in pre-2016 models. Worn rocker arm bearings lead to a distinct ticking noise, misfires, and can eventually cause camshaft damage. (Ref: Subject of class-action lawsuits.)
• Heater Core Clogging 🟠 Medium — Common issue where casting sand from the engine block manufacturing process clogs the heater core, resulting in poor or no heat, particularly on the driver's side. (Ref: Subject of a class-action lawsuit for 2012-2017 models.)
• Left Cylinder Head Defect (2012-2013) 🔴 High — Primarily affects early models (2012-2013). Worn valve guides/seats on the left bank (cylinders 2, 4, 6) cause persistent misfires (P0302, P0304, P0306) and require cylinder head replacement. (Ref: Chrysler TSB 09-002-14; Covered under an extended warranty (X56) for 10 years / 150,000 miles.)

Used vs. New Parts: Buying Guide for This Vehicle

When a used part is the smart pick: A used OEM ignition coil from a low-mileage donor vehicle can be a cost-effective temporary fix, especially if you need to confirm the diagnosis before buying a new part. Given the labor to access cylinder #5, however, installing a new, warrantied part is strongly recommended for the final repair.

Donor-vehicle mileage cap: roughly under 60000 miles for the part to have meaningful remaining life.

What to inspect on the donor part:

• Check for cracks, melting, or any signs of heat damage on the coil housing.
• Ensure the electrical connector pins are clean, straight, and free of corrosion.
• Inspect the coil boot for tears, swelling, or oil contamination.
• If possible, ask the salvage yard for the mileage of the donor vehicle.

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

• Powertrain Control Module (PCM) - Used PCMs often have anti-theft (SKIM) data that makes them incompatible without dealer programming.

Aftermarket brands forum-validated for this vehicle:

• NGK
• Denso
• Bosch

Brands owners have reported issues with on this vehicle:

• Unbranded, 'white-box' ignition coils sold at very low prices on marketplace websites often have high failure rates and may not perform to OEM specifications.

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 — This is the specific cylinder #5 misfire code that almost always accompanies P0355 when the ignition coil or circuit fails.
• P0353 — This code for cylinder #3 ignition coil circuit often appears during the diagnostic process if the technician swaps the suspect coil from cylinder #5 to #3 to confirm a failure.
• P0351 — Identical circuit malfunction code for cylinder #1, which is located on the same passenger-side bank under the intake manifold.
• P0356 — The equivalent ignition coil circuit code for cylinder #6, which is a common failure point on platform mates like the Dodge Charger with the same 3.6L engine.
• P0302 — A misfire code for cylinder #2, often associated with the 2012-2013 left cylinder head defect mentioned in TSB 09-002-14.

Frequently Asked Questions