P0305 on Saturn
Cylinder 5 Misfire Detected
P0305 on Saturn vehicles indicates cylinder 5 misfire detected. Au7o has documented this code across 2 Saturn models — most commonly on Aura, Vue. This code means the engine control module detected a misfire on cylinder number 5, meaning that cylinder is not burning its air-fuel mixture properly on some combustion cycles. The computer senses misfires by watching for tiny fluctuations in crankshaft speed each time a cylinder fails to fire correctly. A misfire wastes fuel, can make the engine run rough or shake, and dumps unburned fuel into the exhaust, which can overheat and damage the catalytic converter. It generally points to a problem with spark, fuel delivery, or compression specifically affecting cylinder 5. Typical repair costs on Saturn range from $150 to $800, depending on the specific model and root cause.
Common Causes of P0305
- •Worn or fouled spark plug on cylinder 5
- •Failed ignition coil or coil pack for cylinder 5
- •Faulty or clogged fuel injector on cylinder 5
- •Vacuum or intake air leak affecting that cylinder
- •Bad spark plug wire or boot (on applicable engines)
- •Low compression from worn rings, valves, or head gasket
- •Carbon buildup or sticking valve on cylinder 5
- •Lean or rich fuel condition affecting the cylinder
P0305 on Saturn by Model
Saturn Aura(1 issue)
- 3.6L Random/Multiple-Cylinder Misfire2007-2009
The 3.6L V6 Auras are reported to throw misfire codes, frequently as a downstream symptom of the stretched timing chains but also from worn ignition coils/spark plugs or carbon buildup on the direct-injection intake valves. Owners experience rough idle, hesitation, and a check engine light. P0300 with cylinder-specific misfire codes is common.
Saturn Vue(1 issue)
- V6 Valve Cover Gasket Oil Leak Soaking Coil Boots → Misfires2004-2007
On the 3.0L and 3.5L V6 Vue models, the valve cover gaskets become brittle and leak oil down into the spark plug tubes. The oil soaks the coil-on-plug boots, causing the rubber to swell and degrade so spark grounds out, producing misfires and rough running. Oil also drips onto the exhaust manifold, creating a burning-oil smell.
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View P0305 across all makes →Frequently Asked Questions
What does P0305 mean on Saturn?▼
P0305 stands for "Cylinder 5 Misfire Detected." This code means the engine control module detected a misfire on cylinder number 5, meaning that cylinder is not burning its air-fuel mixture properly on some combustion cycles. The computer senses misfires by watching for tiny fluctuations in crankshaft speed each time a cylinder fails to fire correctly. A misfire wastes fuel, can make the engine run rough or shake, and dumps unburned fuel into the exhaust, which can overheat and damage the catalytic converter. It generally points to a problem with spark, fuel delivery, or compression specifically affecting cylinder 5. On Saturn specifically, this code is documented across 2 models.
What causes P0305 on Saturn vehicles?▼
Common causes on Saturn: Worn or fouled spark plug on cylinder 5, Failed ignition coil or coil pack for cylinder 5, Faulty or clogged fuel injector on cylinder 5, Vacuum or intake air leak affecting that cylinder, Bad spark plug wire or boot (on applicable engines). Specific causes vary by model and year — see the per-model sections below.
How much does it cost to fix P0305 on a Saturn?▼
Repair costs on Saturn range from $150 to $800, depending on the specific model and root cause.
Which Saturn models have P0305 documented?▼
Au7o has documented P0305 on 2 Saturn models: Aura, Vue.