How To Fix P0358 OBD2 Error Code?

The P0358 OBD-II error code can be defined as the Ignition Coil H Primary/Secondary Circuit Malfunction. The Powertrain Control Module(PCM) or the switching device used in the system which is responsible for the monitoring of signals will light up the Check Engine sign when it receives an error in input from the ignition coils.

What does it mean?

It means that a malfunction is detected in either the primary or secondary circuits of the ignition coil H. The low power voltage side is the primary circuit which includes the battery, ignition switch, primary coil winding, etc. The high power voltage side is the secondary circuit which includes the coil pack and the spark plugs. This error usually means there is a fault in the parts on one of the sides. When the PCM detects malfunctioning inputs from the ignition coil H from either side, this code will be stored.

Error Code P0358: Symptoms, Causes & Fix

Symptoms

When this error code occurs in the system, it can show a lot of symptoms. Some of the symptoms of this error code are:

The main symptom of this error would be the Check Engine sign being lit up. But other than this, there are several other symptoms as well such as:

• There might be difficulty starting the engine at times.
• The engine might also be noisy and run roughly even when it is at an idle state.
• When accelerating, the engine might abruptly lose power or have very little power.
• An overall difficulty in the smooth running of the engine while driving might also be a symptom.
• Engine misfiring can also occur.

Causes

The causes of the P0358 OBD-II error code could be numerous. As the error is detected in the ignition coil, the primary reason could be that the ignition coil itself is defective and needs to be replaced. Other causes could be a poor connection of the ignition coils or broken connector locks. There might also be a leakage in the intake manifold vacuum. The spark plugs or the plug wiring themselves might be faulty. 

How can you diagnose a P0358 OBD-II error code? 

First, to diagnose a P0358 error code, a mechanic or the owner can use an OBD-II scanner to detect which code error has been stored. After doing this, he/she can start by visually assessing the engine parts that have the error such as the ignition coils, circuits, their wirings, connections, spark plugs, etc. If there are any visually faulty or damaged parts, they can replace them with new ones and test the engine by resetting the system.

If no such damage can be seen, replacing the ignition coil with a new pack should be the primary solution. If the new coil when fitted into the system clears the code and helps run the engine smoothly when taken for a test drive, the ignition coil is diagnosed with the problem and is promptly replaced.

If this doesn’t work, then other parts of the engine need to be inspected for faults such as the powertrain control module, engine control module, fuel ignition system, engine wiring connector, spark plugs, and electronic control unit, etc.

Common mistakes while diagnosing the P0358 error code

A common mistake a mechanic or the owner of the vehicle can make while diagnosing this error is that they fail to inspect and check all the parts of the engine thoroughly when this error is first detected. Rushing to replace the ignition coil without first thoroughly checking the Powertrain Control Module, the connections, wirings, circuits, spark plugs, etc. might prove fatal. It could lead to a loss of time and money and cause more frustration for everyone involved.

How do you fix a P0358 error?

Before beginning to fix this error, we need to know how important it is to fix this error as soon as you can. A P0358 error can at first be seen as not so alarming and many drivers fail to get it fixed before it causes serious damage. If this error is left unfixed for long enough, it might cause engine misfiring issues and other knocking and pinging problems which can potentially put the driver and other vehicles around him at risk. Thus, you need to make sure this error is resolved as soon as possible.

First, to fix this error, you need to gather up the necessary tools required for the process. Several parts might be at fault for this error code instead of just the ignition coil. So, you need to be prepared with new ignition coils, electrical wires, soldering irons, wire cutters, connector locks, spark plugs, spark plug wirings, a digital multimeter, wiring harness, etc. After you’re sure you have enough tools that you might require to resolve this error, you need to inspect and check the engine parts and determine which part is faulty or damaged. The most common ways to fix the error might be:

• Replacing the ignition coil with a newer and properly working ignition coil
• Reprogramming the powertrain control module(PCM) or replacing it
• Repairing and strengthening the wiring connections by replacing the wires, connector locks, etc.
• Fixing the open or short wires in the system
• Clearing up any leakage or build-up of carbon in the air passages of the throttle, etc.
• Replacing faulty spark plug or plug wirings.

How do avoid further errors?

To avoid the P0358 OBD-II error code in the future, you should make sure that all your engine functions are working properly. Any indications of difficulty of the engine running smoothly or light-up of any warning signs like the Check Engine sign should not be left unresolved or neglected.

You need to make sure everything is working properly to ensure such errors don’t arise and to ensure the safety of yourself and your passengers. Being up-to-date about the functionality of your engine and whether there are any abnormal changes or issues in the engine while driving however benign it may seem is crucial for the well-being of your engine and your vehicle. 

Routine checkups, servicing, and maintenance of the vehicle and the engine might go a long way in making sure this kind of error code doesn’t arise in your vehicle. So, you should make sure to do this to prevent any permanent damage to your engine or putting you in a dangerous situation while driving.