An ignition coil is one of the major parts of your vehicle engine. It plays a big role in igniting the air-fuel mixture in the combustion chamber. The ignition coil takes voltage from the vehicle battery, transforms it into high voltage, and transfers it to the spark plug. Each engine cylinder contains a coil on plug (COP). Whenever your vehicle’s ignition coil F or its circuit goes bad, your PCM triggers the P0356 code. This article mainly explains the P0356 code symptoms, its causes, and how to fix it.
P0356 Code Definition
P0356 code stands for “Ignition Coil ‘F’ Primary/Secondary Circuit Malfunction.”
What does the P0356 Code Mean?
The P0356 code indicates that your powertrain control module (PCM) detects a potential issue either in the primary or secondary circuit for ignition coil F.
The latest vehicles have a coil on plug (COP) for each engine cylinder. The PCM is used to control the COP.
Placing the ignition coil on top of the spark plug reduces the need for ignition wires. There are two wires to this coil driver that connect to the PCM—one for the PCM coil drive circuit and one for the DC battery power supply. The PCM activates or deactivates the coil by grounding or disconnecting the circuit. The PCM observes the coil driver for errors.
P0356 is triggered when your PCM detects an open or short with the driver coil dedicated to ignition coil F.
Causes of P0356 Code
- Bad COP
- Wiring issues
- An open or short COP driver circuit
- Bad spark plug
- Poor connection
- Vacuum leaks
- COP driver circuit has a short voltage or is ground
- bad PCM
Symptoms of the P0356 Code
- Illuminated check engine light
- Poor engine performance
- Engine misfiring
- Hard to start the vehicle
- Poor fuel economy
Read More: P0355 Code Symptoms and Causes
How to diagnose the P0356 Code?
- Use an OBD-II scanner to download all the stored codes.
- Inspect the ignition coils and the ignition coil driver circuit.
- Inspect the wiring connected to the PCM
- Check the intake manifold to check the vacuum leaks
- Inspect the connector for signs of damage or corrosion
- Inspect the spark plug for corrosion or damage
- Properly inspect the primary ignition coil for damage.
Common P0356 Code Diagnostic Mistakes
- Replacing the parts without testing
- Replacing the unnecessary parts
- Replacing the ignition coil or spark plug without inspecting the damaged wiring or connections.
Repair Cost of P0356 Code
To fix the P0356, you may need one of the below-given repairs:
| Parts | Cost |
| Ignition coil replacement | $160 to $220 |
| Vacuum leak repair | $70 to $380 |
| Spark Plug replacement | $60 to $260 |
| PCM replacement | $240 to $3,000 |
What repairs can fix the P0356 Code?
One or more of the following repairs can fix the P0356 engine code:
- Fixing or replacing the damaged ignition coil
- Repairing or replacing the bad wiring harnesses
- Replacing the bad spark plug
- Fixing the intake manifold leaks
- Fixing the loose connections
- Replacing or reprograming the PCM if needed
FAQ Section
What does engine code P0356 mean?
The P0356 code indicates that your powertrain control module (PCM) detects a potential issue either in the primary or secondary circuit for ignition coil F.
How serious is the P0356 Code?
The P0356 trouble code is considered a serious trouble code. This code produces different drivability issues, such as engine stalling. It may also lead to an engine misfire. Driving with this code is very hazardous. Therefore, you must fix this code as soon as possible.
Which cylinder is P0356?
The P0356 code triggers when the powertrain control module (PCM) observes an issue with the cylinder number 6 ignition coil or its circuit.