P0305 on Honda
Cylinder 5 Misfire Detected
P0305 on Honda vehicles indicates cylinder 5 misfire detected. Au7o has documented this code across 3 Honda models — most commonly on Passport, Pilot, Ridgeline. 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 Honda range from $120 to $8,000, 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 Honda by Model
Honda Passport(2 issues)
- Valve Cover Gasket and Spark Plug Tube Seal Oil Leaks Causing Misfires2000-2002
Aging 3.2L V6 Passports commonly develop oil leaks from the valve cover gaskets and spark plug tube seals. Owners report burnt-oil smell, oil on the cylinder head, and in some cases oil filling the plug wells and causing ignition misfires. This is a typical age-related failure on the Isuzu-sourced V6 and becomes more common as rubber seals harden with heat.
- Timing Belt and Water Pump Neglect Leading to 3.2L V6 Engine Damage2000-2002
The 3.2L V6 used in the first-generation Passport relies on a timing belt service interval that many used examples miss. When the belt, tensioner, or water pump fails, owners report sudden no-starts, stalling, or catastrophic internal engine damage because the engine is interference-design. Forum history and repair databases repeatedly flag overdue timing-belt service as one of the most important reliability risks on these trucks.
Honda Pilot(1 issue)
- Fuel Injector Debris Causing Misfires and Catalyst Codes2016-2018
2016-2018 Pilots suffer from debris in direct-injection fuel system causing internal wear or clogging inside injectors. Causes misfire codes (P0300-P0306), catalyst efficiency codes (P219A/B, P0420/P0430), rough idle, and stalling. TSB 20-100 addresses this defect. Honda extended warranty to 10 years/150,000 miles for 2016-2017 models.
Honda Ridgeline(1 issue)
- Spark Plugs Backing Out - Coil Pack Melting and Engine Damage2006-2010
The 3.5L aluminum engine with steel spark plugs experiences thermal stress due to temperature differences. Spark plugs back out (loosen) due to aluminum block expansion/contraction cycles, causing misfires and potentially breaking inside the combustion chamber. Loose spark plugs allow coil packs to melt and enter the engine block causing catastrophic damage. After 60,000 miles, Honda service bulletins specify spark plug torque should be double-checked. Affects all J35 engine platforms (Pilot, Odyssey, Ridgeline).
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View P0305 across all makes →Frequently Asked Questions
What does P0305 mean on Honda?▼
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 Honda specifically, this code is documented across 3 models.
What causes P0305 on Honda vehicles?▼
Common causes on Honda: 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 Honda?▼
Repair costs on Honda range from $120 to $8,000, depending on the specific model and root cause.
Which Honda models have P0305 documented?▼
Au7o has documented P0305 on 3 Honda models: Passport, Pilot, Ridgeline.