The Quick Answer above is the generic definition. What follows is the model-specific detail for the Audi models that log P0355.
DTC/P0355·Audi
P0355 on Audi: Causes, Symptoms and Fix Cost
Quick Answer
Moderate SeverityNot safe to driveAudi
P0355 on a Audi 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.
Typical repair cost, all makes€55 - €1500
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Audi S5 Coupe (B8, 4.2 FSI V8)
2007-2012The 4.2 FSI V8 is direct-injected, and its other well-known misfire cause, carbon building up on the intake valves, produces misfire codes without any coil circuit code. With P0355 stored, the fault is on the ignition side (coil, plug, connector or wiring), so start there before paying for an intake-valve clean.
What causes P0355 on a Audi?
Beyond the generic causes listed on the main P0355 page, these are the patterns noted for Audi models:
Audi S5 Coupe (B8, 4.2 FSI V8)Coil failure on cylinder 5
Audi S5 Coupe (B8, 4.2 FSI V8)Worn spark plug on cylinder 5
How to diagnose P0355 on a Audi with OBD2
Follow these steps to pinpoint the root cause of 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 on a Audi? (EUR)
Estimated repair costs for P0355 in EUR, compiled across makes. Expect Audi parts and labour towards the upper end of each range.
Prices estimated as of March 2026. Costs vary by region, vehicle, and shop.
Codes related to P0355
These codes are often seen alongside P0355 or point to related issues, on any make:
Looking for the full P0355 reference (all makes, full diagnosis flow, complete repair cost matrix)?
See the main P0355 guideSkanyx · Audi
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