Ignition Coil "B" Secondary Circuit
P2305 indicates a problem with the ignition coil B secondary circuit, which supplies high voltage to the spark plug. The engine control module has detected an electrical fault in the coil pack or its wiring that prevents proper spark generation on one or more cylinders.
What You Might Notice
- Engine misfire or rough idle
- Diminished engine performance and acceleration
- Reduced fuel efficiency
- Check engine light illumination
- Possible engine stalling or hesitation
Most Common Causes
- 1
Faulty ignition coil pack
The ignition coil B has failed internally or the secondary winding is damaged, preventing proper voltage output to the spark plug.
- 2
Corroded or loose coil connector
Poor electrical connection at the coil pack connector due to corrosion, moisture, or improper seating disrupts signal transmission.
- 3
Damaged spark plug wire or boot
If applicable to your vehicle, a cracked or deteriorated secondary wire/boot prevents spark from reaching the spark plug.
- 4
Engine control module circuit issues
Wiring damage, corrosion, or internal PCM failure in the ignition control circuit prevents proper coil triggering.
How to Diagnose It
- 1
Check Faulty ignition coil pack — The ignition coil B has failed internally or the secondary winding is damaged, preventing proper voltage output to the spark plug.
- 2
Check Corroded or loose coil connector — Poor electrical connection at the coil pack connector due to corrosion, moisture, or improper seating disrupts signal transmission.
- 3
Check Damaged spark plug wire or boot — If applicable to your vehicle, a cracked or deteriorated secondary wire/boot prevents spark from reaching the spark plug.
- 4
Check Engine control module circuit issues — Wiring damage, corrosion, or internal PCM failure in the ignition control circuit prevents proper coil triggering.
How to Fix It
- 1
Inspect and clean coil connector
Remove the ignition coil B connector and inspect for corrosion, moisture, or damage. Clean contacts with electrical contact cleaner and ensure proper seating.
- 2
Replace ignition coil pack B
Remove the faulty coil pack from the engine and install a new or remanufactured unit, ensuring proper connector engagement and secure mounting.
- 3
Check and repair wiring harness
Inspect the wiring between the PCM and coil B for breaks, loose connections, or corrosion. Repair or replace damaged sections as needed.
- 4
Verify spark plug condition
Replace the spark plug in the affected cylinder if it is worn, fouled, or damaged, as this can compound ignition coil stress.
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