P2329 indicates a fault in the secondary (high‑voltage) circuit of ignition coil J. The engine control module monitors the coil’s ability to generate sufficient voltage to fire the spark plug; when the secondary circuit shows an open, short, or excessive resistance, the code is set. In most cases the problem lies in the coil, its wiring, or the spark plug, rather than the powertrain control module.
The coil’s secondary winding can open, short internally, or lose insulation, preventing proper high‑voltage generation.
A cracked, fouled, or excessively gapped spark plug can load the secondary circuit and trigger the code.
Open, broken, or chafed insulation on the wire that carries the high voltage from the coil to the spark plug creates high resistance or short circuits.
Moisture, corrosion, or bent pins at the coil’s electrical connector can interrupt the secondary circuit signal.
A short to ground or an open conductor in the wiring between the coil and the ECM can set the code.
The control module itself could fail to properly trigger the coil, but this is an uncommon cause and should be ruled out after checking the coil and wiring.
No. While a faulty PCM can cause secondary‑circuit faults, it is rarely the culprit. The coil, wiring, spark plug, or connector should be investigated first; the PCM should be replaced only after those components are verified good.
Yes. A fouled, cracked, or excessively gapped spark plug can impose too much load on the secondary circuit, leading to a P2329.
Driving with an active misfire can damage the catalytic converter and worsen performance. It is advisable to repair the fault promptly.
In most vehicles the coil is a separate unit and can be replaced individually. If the coil is part of a sealed module, the entire module may need to be swapped.