P0356: Ignition Coil F Primary/Secondary Circuit Malfunction
Can you still drive? Driving with a misfiring cylinder is not recommended. It can damage the catalytic converter and cause further engine issues.
What Does P0356 Mean?
Code P0356 indicates a malfunction in the primary or secondary circuit of ignition coil F, which fires the spark plug in cylinder 6. The ECM has detected an abnormal voltage or signal from the coil pack, meaning the cylinder may not be firing properly. This can lead to misfires, rough running, and increased emissions.
Need to read your codes?
An OBD-II scanner lets you read and clear diagnostic trouble codes from your vehicle's computer. Most scanners work with any car made after 1996.
Browse OBD-II Scanners on AmazonCommon Causes
- Failed ignition coil F
- Damaged wiring or connector to coil F
- Faulty spark plug in cylinder 6
- ECM driver circuit failure
Symptoms
- Check engine light on
- Engine misfire on cylinder 6
- Rough idle
- Reduced engine power
- Poor fuel economy
Diagnostic Steps
- 1Read freeze frame data and note engine conditions at time of fault
- 2Swap ignition coil F with a known good coil from another cylinder
- 3Inspect wiring and connector to coil F for damage or corrosion
- 4Check spark plug in cylinder 6 for wear or fouling
- 5Measure resistance of ignition coil F and compare to specifications
- 6Test ECM coil driver signal with an oscilloscope
Recommended Parts & Tools
Estimated Repair Cost
| Type | Estimated Cost |
|---|---|
| Total Repair Cost Range | $75 - $350 |
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Chat with AI About P0356Commonly Affected Vehicles
Related Recalls
1 Active Recall — 2026 Ford F-150
The following NHTSA safety recalls have been issued for this vehicle. Contact your dealer to check if your vehicle is affected.
ELECTRICAL SYSTEM: INTEGRATED TRAILER BRAKE CONTROL
Ford Motor Company (Ford) is recalling certain 2021-2026 F-150, 2022-2026 F-250 SD, F-350 SD, F-450 SD, F-550 SD, Maverick, 2024-2026 Ranger, 2023-2026 F-600 SD, 2022-2027 Lincoln Navigator, Expedition, and 2026 E-Transit vehicles. When towing a trailer, the integrated trailer module (ITRM) may lose communication with the vehicle, possibly causing a loss of brake and turn signal lights, or a loss of brake function. As such, these vehicles fail to comply with the requirements of Federal Motor Vehicle Safety Standard number 108, " Lamps, Reflective Devices, and Associated Equipment."
Remedy: The integrated trailer module software will be updated by a dealer, or through an over-the-air (OTA) update, free of charge. Owner notification letters are expected to be mailed March 17, 2026. Owners may contact Ford customer service at 1-866-436-7332. Ford's number for this recall is 26C10. Vehicle Identification Numbers (VINs) involved in this recall will be searchable on NHTSA.gov beginning March 17, 2026.
Data provided by the National Highway Traffic Safety Administration (NHTSA).
Frequently Asked Questions
What is ignition coil F?
Ignition coil F is the coil pack responsible for firing the spark plug in cylinder 6. Each cylinder has its own dedicated coil in modern coil-on-plug ignition systems.
Can I replace just one ignition coil?
Yes, you can replace just the failed coil. However, if the coils are original and high-mileage, consider replacing all of them at the same time to prevent repeat failures.
Community Fix Reports
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