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P2305 OBD-II Trouble Code: Ignition Coil "B" Secondary Circuit

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P2305 trouble code definition

P2305 is a general OBD2 diagnostic trouble code (DTC) pointing to a fault within the ignition coil B secondary circuit. This code may be seen with misfire codes and other drivability codes.

What the P2305 code means

The P2305 code means a fault is present in the secondary circuit of the ignition coil B. The ignition coils are used to ramp the electricity up from the battery to provide the spark that ignites the fuel.

When this malfunction is detected a Check Engine Light is enabled and will be visible on the dashboard. In addition to the Check Engine Light, a failsafe mode will be set and remain in effect until the code is repaired or normal operation is found.

What causes the P2305 code?

  • Corroded, intermittent, or poor electrical connection

  • Ignition coil 2 that has failed

  • Open or short in the wiring harness for ignition coil 2

  • Spark plug that has failed

What are the symptoms of the P2305 code?

  • Check Engine Light present of the dashboard
  • Engine misfiring
  • Rough running engine
  • Lack of engine power

How does a mechanic diagnose the P2305 code?

  • Install a scan tool into the DLC port and check for any codes stored in the ECU

  • Note all codes present and the associated freeze frame data

  • Clear all the codes for a fresh start

  • The vehicle will be taken on a test drive under similar circumstances to the freeze frame data.

  • Next, a visual inspection will be performed looking for damaged or worn spark components as well as checking the spark plug coil and wiring.

  • Then the scan tool will be used to monitor the operation of the the secondary ignition coil circuit.

  • Resistance for the coil will be checked.

  • Lastly, the spark plug will be inspected.

Common mistakes when diagnosing the P2305 code

Mistakes can be made with any code if steps are not completed in order or are skipped entirely. All components must be tested and inspected before they are replaced to avoid replacing the wrong components. If parts are not tested before replacement they may not fix the fault.

How serious is the P2305 code?

The P2305 code will not prevent the vehicle from being driven in almost all circumstances. With any codes they should be repaired as soon as possible for normal vehicle operation.

What repairs can fix the P2305 code?

Additional comments for consideration regarding the P2305 code

An important step when diagnosing the P2305 code is the inspection of the spark plugs. If the spark plug electrode is to worn it increases the distance the spark must jump to be able to ignite the fuel. When this happens it increases the resistance for the whole circuit. Check the spark plug gap and compare it to the manufacturer's recommended gap.

Need help with a P2305 code?

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The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details

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