Ignition Coil B Secondary Circuit
What it means
P2305 means the ECM detected a fault in the secondary (high-voltage) circuit of ignition coil 'B'. That cylinder may not spark properly, causing a misfire, rough running, and reduced power. The usual causes are a failed coil, a worn spark plug or boot, or a wiring fault at the coil.
Can I keep driving? Drivable, but the affected cylinder may misfire — sustained misfiring can overheat the catalytic converter, so avoid extended or hard driving until fixed.
Real-world scan data
Figures reflect only diagnostic scans recorded through our own apps and tools. Cars are typically scanned because a symptom or warning light prompted it, so these counts describe our scan records — not the incidence of faults in any model, and not the quality, reliability, or safety of any vehicle. No comparison between manufacturers or models is implied. All trademarks belong to their respective owners; no affiliation or endorsement is implied.
Common symptoms
What you'll notice
- Check-engine light on (may flash during an active misfire)
- Rough idle or hesitation
- Misfire on one cylinder
- Reduced power on acceleration
Common causes
Most likely first
- Faulty ignition coil 'B' (secondary winding)Likely
- Worn spark plug or damaged plug boot on that cylinderCommon
- Coil connector or wiring faultCommon
- Carbon-tracked or arcing secondary circuitLess often
- ECM/PCM coil driver fault (less common)Less often
How to diagnose & fix
Work through it in order
- Identify which physical cylinder maps to coil 'B' for your engine.
- Inspect the coil, plug boot, and spark plug on that cylinder.
- Check the coil connector and wiring for damage or corrosion.
- Swap the suspect coil with a known-good one and see if the code follows it.
- Replace the faulty coil or plug, then clear and re-test.
FAQ
Quick answers
Is it safe to drive with P2305?+
Can I just clear P2305?+
Related codes
Read & clear P2305 yourself
Scan your car, confirm the code, and clear it once it's fixed — with OBD DashX on your phone.