What does code P0306 mean on a Mazda and is it safe to drive?
P0306: Cylinder 6 Misfire Detected. Here's what it means on your Mazda, what usually causes it, what repairs typically cost, and how safe it is to keep driving.
What this code means
Misfire on cylinder 6, found on V6 and V8 engines. On transversely-mounted V6 engines the rear bank cylinders (including cylinder 6) often have higher labor costs due to access difficulty.
Common causes for your Mazda
- Worn spark plug on cylinder 6
- Failed coil-on-plug
- Fuel injector fault
- Low compression
Symptoms
- Check Engine Light, may flash under load
- Rough idle or vibration
- Hesitation and power loss
Typical fixes
- Replace spark plug and COP coil on cylinder 6
- Replace or clean injector on cylinder 6
- Compression and leak-down test if no improvement
Repair cost range
For a Mazda, repairs for P0306 often fall between $150 and $1200, depending on the cause and whether you use OEM or aftermarket parts. Labor rates vary by location.
Known issues on Mazda
Mazda V6 P0306 follows standard COP misfire diagnosis. On AJ-series V6 engines, rear-bank coil boots can crack and cause carbon-tracking arc to ground. Replace both the coil and boot if carbon tracking is visible.
Most commonly affected models