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P0352 Code – What Does It Mean & How To Fix It

This is one of the most frequent OBD2 trouble codes. Read the full article below to know what it means, how to fix it, and what other codes may show related to it.

Definition

The Definition of a P0352 trouble code is “ignition Coil B Primary/Secondary Circuit Malfunction.”

Meaning

The last digit in this particular trouble code indicates that an issue has been detected within the ignition process of cylinder number 2. The coil is basically a transformer that revamps the lower voltage that is supplied by the battery into the higher voltage that spark plugs need to ignite the fuel. 

This process is what makes for a successful combustion process. A coil pack will, on average, will produce around 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 that is needed for the engine’s internal combustion process. 

The coil pack is a high voltage generator that consists of two coils, a single primary coil and one secondary coil as well. 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, which causes 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 the case of this specific trouble code, the detected, malfunctioning coil pack is located above cylinder number 2.

Causes

There are several different events that can cause a P0352 trouble code to occur:

  • Damage or corrosion of the 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.
  • A faulty engine control module. 
  • A faulty coil pack.
  • Defective Spark plug(s).

Symptoms

There are several symptoms that may be indicative that you are dealing with a P0352 trouble code: 

  • A Check Engine Light will be set
  • The engine may misfire. 
  • The driver may experience abnormal vibrations may be felt at idle or while driving. 
  • The vehicle experiences a loss in acceleration. 

Diagnosis

There are a number of steps that an experienced mechanic will need to take in order to properly diagnose this trouble code: 

  • Perform a resistance test on the suspected coil pack. 
  • Inspect the condition of the spark plug electrodes. 
  • Measure the voltage present at the coil pack. 
  • Inspect the wires connecting to the coil packs for fraying, corrosion and at times melting. 
  • Inspect the coil pack circuit for a proper ground supply. 
  • Inspect the intake manifold for vacuum leaks. 
  • Use a multimeter to measure the Hertz signal sent to a coil pack (this helps verify whether the ECM is sending the proper signal to the coil pack). 

Common mistakes

In diagnosing this code, some may overlook the fact that a vacuum leak could cause this code as well. Also, it is not uncommon to neglect measuring 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 this?

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 converter if not addressed quickly enough.

What repairs can fix the code?

The following repairs will fix a P0352 trouble code: 

  • Replacing the coil pack.
  • Replacing the spark plugs.
  • Repairing a vacuum leak such as a leaking intake manifold gasket or cracked vacuum line.
  • Replacing the engine control module.
  • Repair or replacement of any damaged coil pack wiring.

Related codes

None listed.

Conclusion

Because this code can be detrimental to the performance of the vehicle, this can also be a health and safety hazard for the driver as well. As such, this trouble code should be properly diagnosed and fixed as soon as possible.