P1359 Mercury Code - Spark Output Circuit Fault

P1359 indicates a "Spark Output Circuit Fault," meaning the vehicle's engine control module (ECM) has detected an issue in the ignition system's spark output circuit.

Symptoms may include difficulty starting the engine, rough idling, misfires, reduced fuel efficiency, and a lack of power during acceleration.

Common causes include a faulty ignition coil, damaged spark plug wires, a defective ECM, a poor electrical connection in the ignition system, or a short or open circuit in the spark output wiring.

While unlikely, a worn or damaged spark plug can contribute to ignition problems. However, the primary cause is typically related to the spark output circuit or ignition coil.

Start by inspecting the ignition coil, spark plug wires, and connections for damage or corrosion. Use a multimeter to check for proper voltage in the spark output circuit and scan for additional trouble codes.

Driving with this code is not recommended, as it can lead to misfires, reduced performance, and potential engine damage if not addressed promptly.

Repairs may include replacing a faulty ignition coil, repairing or replacing damaged wiring, cleaning corroded connections, or, in rare cases, replacing the ECM if it's defective.

Clearing the code without addressing the underlying issue will only provide a temporary solution. The code will likely return if the root cause is not resolved.

Repair costs vary depending on the cause. Replacing an ignition coil typically costs $150–$300, while wiring repairs or a new ECM can be more expensive.

A DIYer with basic automotive knowledge and tools can often inspect and replace ignition components. However, diagnosing complex electrical issues may require professional expertise.