P0355: Ignition Coil E Primary/Secondary Circuit Malfunction
Quick Answer
Not safe to drive
P0355 means the engine computer saw an electrical fault in the primary or secondary circuit of ignition coil E, which on engines with one coil per cylinder is the coil for cylinder 5. The code only exists on engines with five or more cylinders: five-cylinder engines, inline sixes, V6s, V8s and larger. Most often the coil itself has failed; less often it is the connector, the wiring or the engine computer's driver for that coil.
- Severity
- Moderate · Ignition
- Estimated repair cost
- From €55 to €1500+, varies by vehicle
€55 or €1500, depending on your car.
- Replace ignition coil E (cylinder 5) only€55–€210
- Engine computer repair or replacement (failed coil driver, rare)€500–€1500
A scan shows whether P0355 is really stored on your car, which codes sit next to it and how urgent each one is. You can do this parked, with the ignition on.
A scan needs a Bluetooth OBD2 adapter (Bluetooth LE on iPhone), about €25-60; the built-in demo runs without one. See which adapter to buy
What does P0355 mean?
P0355 is a ignition-related diagnostic trouble code classified as moderate severity.
What are the symptoms of P0355?
- Check engine light on, usually with a cylinder 5 misfire code (P0305) stored as well
- Rough idle with a shake from the one cylinder that is not firing
- Hesitation and loss of power when accelerating
- Check engine light flashing under load while the misfire is active
- Fuel consumption up noticeably
- Raw fuel smell from the exhaust
- Hard starting or a stumble just after a cold start
What causes P0355?
Failed ignition coil on cylinder 5 (open or shorted winding)
: high
Worn or fouled spark plug on cylinder 5 overstressing the coil
: high
Cracked coil boot or plug lead arcing to the cylinder head
: medium
Corroded, loose or oil-soaked connector on the cylinder 5 coil
: medium
Oil in the spark plug well from a leaking valve cover gasket
: medium
Chafed or heat-damaged wire between the engine computer and the coil
: low
Failed coil driver inside the engine computer
: low
Is it safe to drive with P0355?
No - address this immediately. You can limp to a workshop, but a coil that is not firing sends unburned fuel from cylinder 5 into the exhaust, where it overheats the catalytic converter. Get it fixed within a day or two, and if the check engine light flashes, stop driving.
How do you diagnose P0355?
- Read all stored codes and the freeze frame. A cylinder 5 misfire code (P0305) stored alongside P0355 confirms the cylinder is really dropping out, not just logging an electrical glitch.
- Find cylinder 5 in the service data for your engine. Coil E follows the engine's own cylinder numbering, and on V engines that numbering differs from maker to maker.
- Remove the cylinder 5 coil and inspect the boot for cracks, carbon tracks or oil, and the connector for green corrosion, bent or pushed-back pins and a broken locking tab.
- Swap the cylinder 5 coil with the one from cylinder 3, clear the codes and drive. If the fault moves (P0355 becomes P0353), the coil is bad. If P0355 returns, look at the plug, connector and wiring.
- Pull the cylinder 5 spark plug and check the gap, electrode wear and any oil or fuel fouling. A worn plug makes the coil work harder and can kill a new coil quickly.
- Key on, engine off: confirm battery voltage at the coil supply pin against a good ground. While cranking, check that the engine computer is switching the trigger wire with an LED test light or an oscilloscope. Avoid an ordinary bulb test light, which can load the trigger circuit on coils with a built-in igniter.
- Follow the harness towards the engine computer looking for chafing, heat damage or rodent bites, especially where it runs over the back of the engine or close to the exhaust.
- If coil, plug, supply and wiring all pass, the coil driver in the engine computer is the remaining suspect. That needs a workshop with an oscilloscope and the wiring diagram.
How much does P0355 cost to fix?
| Repair | Parts Cost | Labor Cost | Total Estimate | DIY Difficulty |
|---|---|---|---|---|
| Replace ignition coil E (cylinder 5) only | €25–€120 | €30–€90 | €55–€210 | Easy |
| Replace coil E plus the spark plug on cylinder 5 | €35–€150 | €40–€120 | €75–€270 | Easy |
| Full coil set and spark plug set (on a V8, eight of each) | €250–€900 | €120–€350 | €370–€1250 | Moderate |
| Repair coil connector pigtail or harness section | €10–€60 | €60–€180 | €70–€240 | Moderate |
| Valve cover gasket (oil in the plug wells), one cylinder head; V engines at the upper end | €60–€200 | €110–€600 | €170–€800 | Moderate |
| Engine computer repair or replacement (failed coil driver, rare) | €400–€1200 | €100–€300 | €500–€1500 | Professional |
Prices estimated as of October 2026. Costs vary by region, vehicle, and shop.
Full repair guides
P0355 on specific vehicles
P0355 on Chevrolet
Chevrolet Silverado 1500 5.3 V8 (Gen IV)
P0355 on BMW
BMW 5 Series 545i / 550i (N62 V8) · BMW X5 xDrive50i (N63 twin-turbo V8)
P0355 on Audi
Audi S5 Coupe (B8, 4.2 FSI V8)
Related diagnostic codes
Common questions about P0355
- Which cylinder is coil E?
- On engines with one coil per cylinder, coil E is the coil for cylinder 5 by the engine's own numbering. Where cylinder 5 physically sits depends on the layout: on a five-cylinder or inline-six it is towards the back, on a V engine it depends on how the maker numbers the banks. Check the service data before you start swapping parts.
- What is the difference between P0355 and P0305?
- P0305 says cylinder 5 is misfiring, for any reason: spark, fuel, air or compression. P0355 is narrower: the engine computer has seen an electrical fault in the coil E circuit. When both are stored, the ignition side is the place to start.
- Can I swap coils to find out if coil E is bad?
- Yes, and it costs nothing. Swap the cylinder 5 coil with the one from cylinder 3, clear the codes and drive. If P0353 appears, the coil is faulty. If P0355 comes back, the coil is fine and the plug, connector or wiring is the next suspect.
- Will P0355 damage my catalytic converter?
- It can if you keep driving. A cylinder without spark pumps unburned fuel into the exhaust, which burns in the catalytic converter and overheats it. A short drive to a workshop is fine; days of driving with a flashing light are not.
- Should I replace all the coils or just coil E?
- If the coils are original on a high-mileage engine and one has failed, the others have done the same work and may follow. On engines where the coils are quick to reach, replacing only the failed one is reasonable. Where reaching them means removing covers or intake parts, doing the set in one visit saves paying for the same labour twice.
Read our detailed guides
Sources
- en.wikipedia.org en.wikipedia.org/wiki/LS_based_GM_small-block_engine
- chevygeek.com chevygeek.com/ls-firing-order/
- apextechnation.com apextechnation.com/articles/gm-53-v8-common-problems
- en.wikipedia.org en.wikipedia.org/wiki/BMW_N62
- europremiumparts.com europremiumparts.com/blogs/bmw-buying-guides/bmw-n62-engine-guide-reliability-co
- companyofcars.com companyofcars.com/promotions/bmw-n62-n63-valve-stem-seal-repair/
- en.wikipedia.org en.wikipedia.org/wiki/BMW_N63
- alexsautohaus.com alexsautohaus.com/bmw-n63-common-problems/
- en.wikipedia.org en.wikipedia.org/wiki/Audi_S5
- 034motorsport.com 034motorsport.com/service/audi-volkswagen-carbon-cleaning-service-direct-injecte