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OBD2.help›Powertrain›P0356

P0356

Ignition Coil F Primary/Secondary Circuit Malfunction

The engine computer sees an electrical problem in the ignition coil F circuit. That usually means one cylinder is losing spark because the coil, wiring, connector, power feed, ground, or PCM control circuit is not working correctly.

SEV
4/5
DRIVE
CAUTION
DIY
$20-$180
SHOP
$120-$600

Quick answer

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What it means

P0356 means the PCM detected an electrical fault in the ignition coil F primary or secondary circuit. On most coil-on-plug engines, coil F is usually the sixth coil in the firing group, but the exact cylinder mapping depends on the vehicle. The PCM can set this code when it sees an open circuit, short to power, short to ground, missing coil control signal, or abnormal feedback from the coil circuit.

Can you drive with it?

With caution. You may be able to drive a short distance, but do not keep driving a heavy misfire. A flashing check engine light, strong shaking, fuel smell, or major power loss means stop and diagnose it before catalytic converter damage gets worse.

Most common causes

  • Failed ignition coil F
  • Loose, damaged, oil-soaked, or corroded coil connector or wiring
  • Worn or cracked spark plug overloading the coil

Typical repair cost

DIY usually runs $20-$180. Typical shop repair lands around $120-$600, depending on the root cause.

01 / Definition

P0356 means the PCM detected an electrical fault in the ignition coil F primary or secondary circuit. On most coil-on-plug engines, coil F is usually the sixth coil in the firing group, but the exact cylinder mapping depends on the vehicle. The PCM can set this code when it sees an open circuit, short to power, short to ground, missing coil control signal, or abnormal feedback from the coil circuit.

02 / Drive status

With caution. You may be able to drive a short distance, but do not keep driving a heavy misfire. A flashing check engine light, strong shaking, fuel smell, or major power loss means stop and diagnose it before catalytic converter damage gets worse.

03 / Symptoms

  • Check engine light
  • Cylinder misfire
  • Rough idle
  • Engine shaking under load
  • Poor acceleration
  • Hard starting
  • Raw fuel smell from exhaust
  • Flashing check engine light in severe cases

04 / Causes

1Failed ignition coil Fhigh
2Loose, damaged, oil-soaked, or corroded coil connector or wiringhigh
3Worn or cracked spark plug overloading the coilmedium
4Lost coil power feed, blown fuse, bad relay, or weak groundmedium
5Harness short or open between the coil and PCMmedium
6PCM driver circuit faultlow

05 / Diagnostic sequence

  1. 01Check for related codes first, especially P0306, P0350, and other ignition coil circuit codes.
  2. 02Review freeze frame data so you know whether the fault happened at idle, load, or cold start.
  3. 03Inspect coil F, the coil boot, and the connector for cracks, oil intrusion, water, loose pins, or heat damage.
  4. 04Verify battery voltage on the coil power feed and confirm the ground and PCM trigger circuit are intact.
  5. 05Swap the coil with another cylinder if the engine layout allows it and see whether the misfire or companion code follows the coil.
  6. 06Inspect the spark plug on the affected cylinder for worn electrodes, fouling, cracking, or incorrect gap.
  7. 07Check the harness from the coil back to the PCM for rub-through, opens, shorts, or high resistance.
  8. 08If the coil, plug, feed, ground, and wiring test good, then check the PCM driver only after the rest of the circuit is proven.

06 / Repairs

1Replace the failed ignition coil if the fault follows the coil or the coil fails testing$40-$180
2Repair damaged wiring, loose pins, or corroded coil connector terminals$20-$200
3Replace the spark plug on the affected cylinder if it is worn, cracked, or fuel fouled$10-$80
4Repair lost power feed, blown fuse, relay fault, or poor ground in the coil circuit$20-$150
5Repair the PCM control circuit or replace the PCM only if circuit testing proves the driver is bad$200-$1,000

07 / Related codes

  • P0350
  • P0351
  • P0352
  • P0353
  • P0354
  • P0306

08 / FAQ

What does ignition coil F mean?

It usually means the sixth ignition coil in the system, but some engines map coil letters differently. Use service information to confirm which cylinder coil F actually serves.

Can a bad spark plug cause P0356?

Yes. A worn or cracked plug can overload the coil and help trigger a coil circuit code, especially if the coil has already been running hot.

Will replacing the coil always fix P0356?

No. Coils are common, but wiring damage, connector pin fit, power supply problems, and PCM driver faults can set the same code.

Is P0356 the same as a cylinder 6 misfire code?

No. P0356 is a coil circuit fault code. It often causes a cylinder 6 misfire code such as P0306, but the fault is aimed at the ignition circuit, not just the misfire symptom.

09 / Source and method

DATA BASIS
OBD-II REFERENCE + OBD2.HELP
METHOD
STATIC VALIDATION
SAFETY
INFORMATIONAL

This page combines OBD-II diagnostic reference data with OBD2.help generated diagnostic guidance for code meaning, likely causes, and repair direction.

Publishing uses deterministic schema and build validation, plus manual spot checks on representative pages before release.

Safety-critical diagnosis and repairs should be confirmed with a qualified mechanic, especially when the vehicle is misfiring, overheating, or losing power.