Drivable short-term, but fix now to avoid damage.
This code means the engine computer detected an electrical fault in the primary or secondary circuit of ignition coil D (typically cylinder 4). It most often comes from a failed ignition coil, though damaged wiring or a faulty connector can also set it. It's a common code on coil-on-plug engines and is usually fixed by replacing the affected coil and inspecting its wiring.
$90 – $300
Varies by vehicle and root cause.
For short trips, usually yes, but you shouldn't rely on it. A misfiring coil can damage your catalytic converter and leave you with weak power. Get it diagnosed soon and avoid hard acceleration until then.
Most repairs run between $90 and $300. A single ignition coil and labor are usually inexpensive, but wiring repairs or replacing a fouled spark plug can add a bit to the total.
It's worth taking seriously. The car may still run, but the misfire it causes can harm the catalytic converter and worsen over time. It's generally an affordable fix when caught early.
The 'D' identifies a specific ignition coil, which on most engines corresponds to cylinder 4. The code points the technician straight to that coil's circuit, making the fault easier to locate and repair.