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P0352 — Ignition Coil B Primary Control Circuitopen

Generic OBD-II · all makesPowertrain (engine & transmission)

Code P0352 indicates that the engine computer has detected an open circuit in the primary control circuit for ignition coil B. This means the electrical path required to trigger the coil is broken, preventing the spark plug from firing.

Symptoms

What causes it — most likely first

1. Failed Ignition Coil

An internal electrical failure or open winding within the ignition coil itself.

2. Wiring Damage

Frayed, broken, or rodent-damaged wires in the primary control circuit.

3. Corroded Connectors

Corrosion or moisture in the coil connector pins preventing a secure electrical connection.

4. Blown Fuse

A blown fuse in the ignition system power circuit, if applicable to that specific coil.

5. PCM Failure

An internal failure of the ignition coil driver circuit within the engine control module.

How it's diagnosed

  1. Retrieve OBD-II codes to confirm P0352 and check for accompanying misfire codes.
  2. Visually inspect the wiring harness and connector at coil B for burns, breaks, or corrosion.
  3. Test the ignition coil's primary resistance using a multimeter to check for internal opens.
  4. Perform a continuity test on the wiring between the coil connector and the PCM.
  5. Swap the coil with a known good coil from another cylinder to see if the fault follows the component.
  6. Verify the PCM is sending the trigger signal using an oscilloscope or diagnostic test light.

Code facts & related codes

SystemPowertrain (engine & transmission)
StandardizationSAE generic — identical on every make
Related codesP0350 — Ignition Coil Primarysecondary CircuitP0351 — Ignition Coil Primary Control CircuitoP0353 — Ignition Coil C Primary Control CircuiP0354 — Ignition Coil D Primary Control CircuiP0355 — Ignition Coil E Primary Control CircuiP0356 — Ignition Coil F Primary Control Circui

Frequently asked

Does this code mean I need a new engine computer (PCM)?

Rarely. While a PCM failure can cause this code, it is far more common for the coil or its associated wiring to be the cause. The PCM should only be replaced after the coil and wiring have been thoroughly tested and ruled out.

Can I just replace the spark plugs to fix this?

No. This code refers to the primary electrical circuit that powers the coil; spark plugs are the end-point of the system and do not cause an 'open circuit' code in the control wiring.

Is it safe to drive with code P0352?

It is not recommended. Running on fewer cylinders causes excessive vibration and can lead to overheating or permanent damage to the catalytic converter due to unburned fuel.