What does code P0305 mean on a Smart and is it safe to drive?
P0305: Cylinder 5 Misfire Detected. Here's what it means on your Smart, what usually causes it, what repairs typically cost, and how safe it is 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 for your Smart
- 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 Smart, repairs for P0305 often fall between $150 and $1000, depending on the cause and whether you use OEM or aftermarket parts. Labor rates vary by location.