P0352 OBD-II Trouble Code: Ignition Coil B Primary/Secondary Circuit Malfunction

Check Engine Light

P0352 code definition

Ignition Coil B Primary/Secondary Circuit Malfunction

What the P0352 code means

The last digit in this particular trouble code indicates that there is an issue detected within the ignition process of cylinder number 2. The coil is essentially a transformer which revamps the lower voltage supplied by the battery into the higher voltage that spark plugs need to ignite the fuel for a successful combustion process. A coil pack will on average will produce about 70,000 to 100,000 Volts.

A coil pack, also known as a coil on plug or an ignition coil, is used to convert the standard battery voltage into the higher voltage needed for the internal combustion process of an engine. The coil pack is characteristically a high voltage generator consisting of two coils, one primary coil and one secondary coil. The large primary coil receives the initial voltage from the battery and transfers it to the smaller secondary coil. The secondary coil is located inside the primary coil, and spins at rapid rates within the primary coil, causing a magnetic field. This, in turn, helps induce the high voltage and amperage needed to ignite the fuel during the combustion process.

A trouble code P0352 may set if the Engine Control Module (ECM) detects an issue with the ignition process of the coil pack. In this case, the coil pack detected as malfunctioning is located above cylinder number 2.

What causes the P0352 code?

  • Damaged or corroded wiring of the second cylinder coil pack

  • Damage or corrosion of the wires connecting the second cylinder coil pack to the Engine Control Module

  • Open or short in the wiring of the electrical circuit of the second cylinder coil pack

  • Faulty Engine Control Module

  • Faulty coil pack

  • Defective Spark plug(s)

What are the symptoms of the P0352 code?

  • A Check Engine Light being set
  • Engine misfire, abnormal vibrations may be felt at idle or while driving
  • Loss of acceleration

How does a mechanic diagnose the P0352 code?

  • Performs a resistance test on the suspected coil pack

  • Inspects the condition of the spark plug electrodes

  • Measures the voltage present at the coil pack

  • Inspects the wires connecting to the coil packs for fraying, corrosion and at times melting

  • Inspects the coil pack circuit for a proper ground supply

  • Inspects the intake manifold for vacuum leaks

  • Uses a multimeter to measure the Hertz signal sent to a coil pack (helps verify whether the ECM is sending the proper signal to the coil pack)

Common mistakes when diagnosing the P0352 code

Some may overlook the fact that a vacuum leak could cause this code as well. Also, some may neglect to measure the hertz signal that should be sent by the ECM to the coil pack. Measuring the Hertz signal will help you determine if the Engine Control Module is faulty, or if there is an interruption in the coil pack circuit, such as corrosion build up or damaged wiring.

How serious is the P0352 code?

It is fairly serious because you can not legally pass inspection with a Check Engine Light on. Driving with a misfire is bad for the engine because if one cylinder is hindered, the other cylinders will have to work twice as hard to run the vehicle. Doing so will stress the other cylinders and cause parts such as piston rings, spark plugs and other coil packs to wear more quickly. This code is known to cause an engine misfire, which will damage or clog the catalytic convertor if not addressed quickly enough.

What repairs can fix the P0352 code?

Additional comments for consideration regarding the P0352 code

It is strongly suggested to check the Hertz signal from the ECM to the coil pack. Also, it is recommended to check the intake manifold for vacuum leaks.

Need help with a P0352 code?

YourMechanic offers certified mobile mechanics who will come to your home or office to diagnose and repair your vehicle. Get a quote and book an appointment online or speak to a service advisor at 1-800-701-6230.

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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