P1363
FordIgnition Coil D Secondary Circuit Malfunction
The vehicle has detected a fault in the secondary ignition circuit identified as Coil D. The coil helps produce the high voltage needed for a spark; a problem in its secondary path can cause weak or missing spark and may affect engine operation. This code does not prove the coil itself has failed. The exact Coil D identification and diagnostic procedure depend on the vehicle's model, year, and engine.
⚠️ Before You Begin (Safety First)
If the engine is shaking badly, losing power, or the check-engine light is flashing, stop driving when it is safe to do so. Continued driving with a severe misfire can overheat and damage the catalytic converter. Keep hands and tools away from ignition components while the engine is running; ignition voltage can cause a shock.
Common Symptoms
- The check-engine light may be on, with no noticeable change in how the engine runs.
- An intermittent or weak spark may cause rough running, hesitation, or a misfire.
- A persistent misfire may reduce power and fuel economy.
- A flashing check-engine light may occur with a severe active misfire.
Common Causes
- An internal fault in the ignition coil's secondary circuit.
- A damaged, worn, or incorrectly fitted spark plug or coil boot, where used.
- A loose, corroded, contaminated, or damaged connection in the secondary ignition path.
- Damaged wiring or insulation that allows the ignition voltage to leak or fail to reach the spark plug.
- A related ignition-control fault; testing is needed to distinguish it from a coil or secondary-path problem.
Diagnostic Steps
- With the engine off and cool, note any other stored codes and whether the engine has rough running or power loss; these details help narrow the fault.
- Use the vehicle's service information to identify Coil D for the exact engine. Do not assume its cylinder location from the code alone.
- Inspect the accessible coil connector and wiring for looseness, damage, corrosion, or contamination. Do not disconnect or handle ignition components while the engine is running.
- If accessible and appropriate for the vehicle, inspect the coil boot and spark-plug well for damage, moisture, oil, or signs of arcing. Avoid probing ignition high-voltage parts.
- If the code returns or the engine misfires, have the secondary circuit and related ignition components tested using vehicle-specific procedures before replacing parts.
When to Call a Professional
Use scan data to check for misfire activity and related codes, then inspect the Coil D secondary path, including the coil, boot, spark plug, and connections as applicable. Check wiring and connectors before condemning a part. Use vehicle-specific service information for component identification and electrical tests; replace a component only after testing supports that diagnosis.
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Commonly Asked Questions
Does P1363 mean the ignition coil must be replaced?
No. It identifies a fault in the Coil D secondary circuit, not proof that the coil itself is defective. The plug, boot, wiring, connections, or an ignition-control issue may also need to be checked.
Does Coil D identify a particular cylinder?
Not reliably without the vehicle's model, year, and engine information. Use vehicle-specific service information to identify the component.
Can I keep driving with P1363?
If the engine runs normally and the check-engine light is steady, arrange diagnosis soon and watch for changes. Stop when safe if the light flashes or the engine shakes badly or loses significant power.
What does a technician check first?
A technician can review related codes and misfire data, inspect the Coil D secondary path and connections, and test the relevant components using procedures for that vehicle.
Browse Available Code Guides
Previous and next available guides in database record order, across makes. Adjacent entries may share a code number and do not necessarily describe related faults.