Code Definition

P2304 — Ignition Coil “B” Primary Control Circuit High

System: Powertrain  |  Type: Generic (OBD-II Standard)  |  Make: Generic

About P2304

P2304 is a generic (obd-ii standard) powertrain diagnostic trouble code. It belongs to the P-prefix family of codes, which covers engine, transmission, emissions, or fuel-system faults.

When P2304 is stored, the module has detected a signal or supply voltage higher than the expected operating range.

Scanning & clearing: A generic OBD-II scan tool will usually read and clear powertrain (P) codes. For live data, freeze-frame capture, and bi-directional tests you may need a more capable scan tool that supports the vehicle's ECM protocol.

Because P2304 is a generic OBD-II code, its base definition is shared across manufacturers. The specific diagnostic steps, reference values, and repair procedures can vary by vehicle, and the TaT Diagnostic Assistant includes verified procedures submitted by working technicians.

Code Information

DTC P2304 indicates a high voltage condition in the primary control circuit of ignition coil B. The control module fires the coil by switching its primary control wire to ground, and the code sets when the module measures a higher than expected voltage on the coil B primary control circuit while commanding the coil on, showing the circuit is not being pulled low. The usual causes are an open or high resistance in the control wiring or power feed, a coil B primary winding fault, or a module driver problem. The result is typically a misfire on the cylinder served by coil B, with rough running, r...

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