P0356

Code

Generic P — Powertrain

Ignition Coil F Primary Control Circuit/Open

Brand: Generic

Type: P — Powertrain

Views: UK: 30 EN: 44 RU: 46

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Page language: EN

Causes

Open or short in the ignition coil primary wiring (open, short to power, or short to ground).
Corroded, loose or damaged coil electrical connector or terminals.
Failed ignition coil (internal open or short in primary winding).
Blown fuse or faulty ignition power/relay supplying the coil pack.
Poor or missing ground at coil pack or engine/chassis.
Faulty PCM/ignition driver (less common).

Symptoms

Check Engine Light (MIL) illuminated.
Stored or pending misfire codes for the same cylinder (e.g., P0306 if coil F is cylinder 6).
Rough idle, hesitation, stumble under load, reduced power.
Reduced fuel economy.
Possible engine misfire felt as a jerk or vibration.

What to check

Read and record freeze-frame data and related misfire/ignition codes with a scan tool.
Identify which cylinder corresponds to 'Ignition Coil F' per vehicle service manual.
Visually inspect coil pack and connector for damage, corrosion, melted plastic, or oil/water contamination.
Check fuses and ignition relay that supply coil power for continuity and operation.
Measure coil primary and secondary resistance (compare to manufacturer specifications).
Check wiring continuity between coil connector and PCM ignition driver pin; check for shorts to battery or ground.

Signal parameters

Coil primary resistance (typical): ~0.3 to 2.0 ohms (varies by coil design) — consult vehicle spec.
Coil secondary resistance (typical): ~5 kΩ to 15 kΩ (varies) — consult vehicle spec.
Uncommanded (idle/off) coil positive terminal: battery voltage (~12 V).
PCM command on coil primary/driver: when commanded to fire, driver typically grounds or pulls the primary to low voltage; primary circuit should show switching/grounding pulses during crank/firing.
Open-circuit condition: infinite/very high resistance in primary or no switching pulses present on oscilloscope/noid light.

Diagnostic algorithm

Verify code and related codes with a scan tool. Note freeze frame and engine conditions when fault set.
Identify which engine cylinder is controlled by 'Ignition Coil F' using OEM documentation.
Visually inspect the coil assembly, connector, wiring harness and PCM connector for obvious damage, corrosion, or signs of arcing or heat.
Check ignition power fuse(s) and relay(s). Replace/repair if blown or faulty.
Measure coil primary resistance at the coil connector (unplugged). Compare to spec. A very high or infinite reading indicates open primary (replace coil).
Measure coil secondary resistance if applicable and compare to spec. Out-of-spec secondary indicates a bad coil.
With connector attached, backprobe the coil driver/primary terminal and monitor with a lab scope or multimeter while cranking: look for switching pulses or ground command from PCM. No pulses suggests open wiring or PCM driver issue.
Check continuity between the coil connector and the PCM driver pin; verify there is no short to battery or chassis ground and no high resistance. Wiggle wiring near harness entry points while monitoring for intermittent faults.
Swap coil F with a known-good coil from another cylinder (if identical) and clear codes. If code follows the coil, replace coil. If code stays on original cylinder, suspect wiring or PCM.
If wiring and coil are good but no driver signal, test PCM driver output and related circuitry per manufacturer procedure. Repair or replace PCM only after confirming wiring and coil are good.
After repair, clear codes and perform a road test or drive cycle to confirm the issue is resolved and code does not return.

Likely causes

Faulty ignition coil (most common).
Damaged connector or wiring harness to coil F (pin corrosion, broken wire at flex point).
Open circuit or high resistance in the coil primary leading to lack of current.
Blown/failed ignition power fuse or relay affecting coil pack supply.
PCM driver fault (rare) after wiring and coil are verified good.

Fault status

⚠️ Status

The PCM detected an open or abnormal condition in the primary control circuit for ignition coil F (no expected primary current/command signal). The circuit is not responding within expected voltage or switching parameters.

🟡 Repair difficulty: Medium

⏱️ Diagnostic time: 0.5-2.0 hours

Repair manuals