P2308

Ignition Coil C Secondary Circuit

Q: 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.

Q: 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.

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.

Real-world scan data

Seen in

scans in the past year

Found in

<0.1%

of scans

<0.1%

of scans that found faults

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

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.

Read & clear P2308 yourself

Scan your car, confirm the code, and clear it once it's fixed — with OBD DashX on your phone.

▶ Get it on Google Play

✓ Verified name — SAE J2012 / ISO 15031-6Guidance reviewed by OBD DashX