2021 Jeep P0306: What It Means & Is It Safe to Drive?
P0306 on the 2021 Jeep: Cylinder 6 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 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 on the 2021 Jeep
- 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 2021 Jeep, repairs for P0306 typically fall between $150 and $1200, depending on the root cause and labor rates in your area.
Known issues on Jeep
Jeep 3.6L Pentastar P0306 is on the rear bank. On HEMI models, cylinder 6 is not an MDS deactivation cylinder—P0306 on the HEMI typically means a coil or plug failure rather than a lifter issue.
Most commonly affected models
Grand Cherokee 3.6L Pentastar 2011–2020Grand Cherokee 5.7L HEMI 2005–2010