P0352 serious

Ignition Coil B Primary/Secondary Circuit Malfunction

What does P0352 mean?

The P0352 code means the vehicle's onboard diagnostic system has detected: Ignition Coil B Primary/Secondary Circuit Malfunction. This is a serious severity code.

Common Symptoms

  • Misfire on cylinder(s) served by coil B
  • Rough idle
  • Check Engine Light on or flashing
  • Power loss

Probable Causes (Ranked by Likelihood)

  • Failed ignition coil pack or coil-on-plug unit (coil B) Very High
  • Open or shorted wiring to coil B High
  • Faulty ignition control module Low

Step-by-Step Diagnostic Procedure

  1. Swap coil B with a known-good coil from another position. If the misfire follows, replace the coil.

  2. Test primary coil resistance: 0.4-2 ohms. Test secondary resistance: 6,000-15,000 ohms.

  3. Inspect coil connector for carbon tracking, corrosion, or melted terminals.

  4. Verify 12V supply and ground to the coil connector.

Frequently Asked Questions

Which cylinder is coil B?

Coil designations (A, B, C...) correspond to cylinders in firing order sequence, not necessarily the physical cylinder number. On most Ford and GM applications, coil B corresponds to cylinder 2. Consult your service manual.

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