P0354 indicates a problem with the primary control circuit of ignition coil D. The PCM has detected an open condition in the circuit that supplies voltage to that coil.
The coil's internal primary windings can fail, creating an open circuit that prevents proper spark.
A broken wire, loose terminal, or short in the harness leading to coil D will interrupt the circuit.
Oxidation or poor contact in the connector can increase resistance and cause an open condition.
The PCM's internal driver may be damaged, but this is uncommon and typically only after extensive electrical testing.
Severe engine overheating or timing issues can stress the coil, but this is a secondary factor.
No. In the vast majority of cases the problem is a faulty coil, wiring, or connector; the PCM is rarely the cause.
A fouled plug can cause misfires but does not directly trigger a primary circuit open code; the issue must be in the coil circuit itself.
Driving may be possible for a short distance, but the engine will run rough and could cause additional damage if the misfire persists.
Not necessarily. Only the affected coil or its circuit needs attention; replacing all coils adds unnecessary cost.