What does code P0351 mean on a Mercedes-Benz and is it safe to drive?
P0351: Ignition Coil A Primary/Secondary Circuit Malfunction. Here's what it means on your Mercedes-Benz, what usually causes it, what repairs typically cost, and how safe it is to keep driving.
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What this code means
The PCM detected a fault in the primary or secondary circuit of ignition coil A (cylinder 1 coil on most coil-on-plug systems). This will cause a misfire on the affected cylinder and can damage the catalytic converter if left unresolved.
Common causes for your Mercedes-Benz
- Failed ignition coil
- Fouled or worn spark plug on that cylinder
- Damaged ignition coil wiring or connector
- Faulty PCM output driver (rare)
Symptoms
- Check Engine Light on, often flashing
- Rough idle and misfire
- Loss of power
- Poor fuel economy
Typical fixes
- Replace ignition coil for cylinder 1
- Replace spark plug on affected cylinder
- Inspect coil wiring and connector
Repair cost range
For a Mercedes-Benz, repairs for P0351 often fall between $80 and $300, depending on the cause and whether you use OEM or aftermarket parts. Labor rates vary by location.