P2308
Ignition Coil C Secondary Circuit
Ignition system
Generic OBD-II
High
What it means
P2308 means the ECM has detected a fault in the secondary (high-voltage) side of ignition coil C — the part that delivers spark to the plug. This usually causes a misfire on that cylinder, with rough running and lost power. The common causes are a failing coil, a worn plug or boot, or arcing in the coil-to-plug connection.
High
Can I keep driving? Not ideal — a coil secondary fault usually means a misfire on that cylinder; extended driving risks catalytic-converter damage, so fix it soon.
Common symptoms
What you'll notice
- Misfire on one cylinder
- Rough idle, shaking, or hesitation
- Loss of power on acceleration
- Check-engine light on (may flash during an active misfire)
- Poor fuel economy
Common causes
Most likely first
- Faulty ignition coil CLikely
- Worn spark plug or damaged plug boot/wire on that cylinderCommon
- Fault in the secondary (high-voltage) coil-to-plug connectionCommon
- Carbon tracking or arcing at the coil/plugLess often
- ECM ignition driver fault (less common)Less often
How to diagnose & fix
Work through it in order
- Identify which cylinder is coil C for your engine's coil layout and read freeze-frame data.
- Swap coil C with a neighbouring coil and see if the fault follows the coil.
- Inspect the spark plug and boot on that cylinder for wear or arcing.
- Check the coil's secondary connection and the plug for carbon tracking.
- Replace the coil or plug as indicated, then clear and re-test.
FAQ
Quick answers
Is it safe to drive with P2308?+
Keep it brief. A secondary-circuit fault usually causes a misfire, and sustained misfiring can overheat and damage the catalytic converter — especially if the light is flashing.
Can I just clear P2308?+
It returns quickly while the coil or spark path is faulty. Clearing it won't restore the missing spark on that cylinder.
Related codes
Often seen with P2308
Read & clear P2308 yourself
Scan your car, confirm the code, and clear it once it's fixed — with OBD DashX on your phone.
✓ Verified name — SAE J2012 / ISO 15031-6Guidance reviewed by OBD DashX