2020 Mazda P0305: What It Means & Is It Safe to Drive?
P0305 on the 2020 Mazda: Cylinder 5 Misfire Detected. Here's what it means, what usually causes it, what repairs typically cost, and whether it's safe to keep driving.
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What this code means
Misfire on cylinder 5—present on V6, V8, and inline-5 engines only. On V6 engines, cylinder 5 is sometimes harder to access; factor labor into repair estimates.
Common causes on the 2020 Mazda
- Fouled spark plug
- Failed ignition coil
- Leaking or clogged injector
- Low compression from valve or ring wear
Symptoms
- Check Engine Light
- Engine shaking or rough idle
- Power loss under acceleration
Typical fixes
- Replace spark plug and coil on cylinder 5
- Test and replace injector if needed
- Compression and leak-down test
Repair cost range
For a 2020 Mazda, repairs for P0305 typically fall between $150 and $1000, depending on the root cause and labor rates in your area.
Known issues on Mazda
Mazda V6 engines see P0305 from individual COP failures. On the older MZR-3.0 and AJ V6, coil-on-plug boots can crack and arc causing intermittent misfires. Inspect boot condition during plug replacement on these higher-mileage engines.
Most commonly affected models
Mazda6 V6 2.3L 2003–2008MPV V6 3.0L 2000–2006CX-9 V6 2007–2015