P0356 Ignition coil F primary/secondary circuit malfunction

P0356 – OBD-II Trouble Code Technical Description

Ignition coil F. Primary/secondary circuit malfunction.

What does the fault code mean P0356?

This Diagnostic Trouble Code (DTC) refers to common transmission codes that apply to vehicles with the OBD-II system. Despite its general nature, the specifics of the repair may vary depending on the make and model of the vehicle. The COP (coil-on-plug) ignition system is common in modern engines. Each cylinder has its own coil controlled by the PCM (powertrain control module). This system eliminates the need for spark plug wires because the coil is placed directly above the spark plugs. Each coil has two wires: one for battery power and one for PCM control. If a fault is detected in the control circuit of one of the coils, for example, coil No. 6, a P0356 code may occur. Additionally, the PCM may disable the fuel injector in that cylinder to prevent further damage.

Modern PCM-equipped vehicles typically use a COP (coil-on-plug) ignition system, where each cylinder has its own coil controlled by the PCM. This simplifies the design and eliminates the need for spark plug wires. The PCM controls each coil through two wires: one for battery power and the other for the coil control circuit. If an open or short circuit is detected in the No. 6 coil control circuit, code P0356 occurs. On some vehicles, the PCM may also disable this coil's fuel injector to avoid additional problems.

Possible reasons

Code P0356 can occur in a vehicle's PCM for a variety of reasons, including:

1. Malfunction of ignition coil (IC) No. 6.
2. Coil #6 connection problems such as loose connection.
3. Damage to the connector connected to coil No. 6.
4. Open circuit in the KS driver circuit.
5. The COP driver circuit is shorted or grounded.
6. In unlikely cases, the problem may be due to a faulty PCM that is not functioning properly.

Other possible causes of a P0356 code include:

• Short circuit to voltage or ground in the COP driver circuit.
• Open circuit in the COP driver circuit.
• Loose coil connection or damaged connector locks.
• Bad coil (CS).
• Faulty engine control module (ECM).

What are the symptoms of a fault code? P0356?

Symptoms of a P0356 trouble code include:

• MIL (malfunction indicator) lighting.
• Engine misfires, which can occur periodically.

This code is often accompanied by the following symptoms:

• The check engine light (or engine maintenance light) comes on.
• Loss of power.
• Complicating the process of starting the engine.
• Fluctuations in engine operation.
• Rough engine idling.

Note that the check engine light may come on immediately after this code appears, although some models may delay the light activating or the code recording after multiple incidents.

How to diagnose a fault code P0356?

The mechanic will begin a diagnosis using an OBD-II scanner to retrieve the stored codes. Next, he will check the ignition coil and ignition coil driver circuit, and inspect the wires connected to the PCM.

If the engine is currently misfiring, the problem may be intermittent. In this case, you can do the following:

1. Check the #6 coil wiring and wiring harness to the PCM using the jiggle method. If this is causing the misfire, inspect and, if necessary, repair the wiring problem.
2. Check the contacts in the coil connector and make sure that the harness is not damaged or chafed.

If your engine is currently misfiring, follow these instructions:

1. Stop the engine and disconnect the #6 coil wiring connector.
2. Start the engine and check for a control signal at coil #6 using a voltmeter on the AC Hertz scale. If there is a Hertz signal, replace the #6 ignition coil.
3. If there is no Hertz signal or visible pattern on the scope, check the DC voltage in the driver circuit at the coil connector. If significant voltage is detected, locate and repair the short to voltage in the circuit.
4. If there is no voltage in the driver circuit, turn the ignition switch off, disconnect the PCM connector, and check the continuity of the driver circuit between the PCM and the ignition coil. Repair open or short to ground in the circuit.
5. If the ignition coil driver signal wire is not open or shorted to voltage or ground, and the coil fires correctly but P0356 keeps resetting, then you should consider a PCM coil monitoring system failure.

Remember that after replacing the PCM, it is recommended to perform the test described above to ensure that it is operating reliably and does not fail again.

Diagnostic errors

Sometimes mechanics rush through the service without paying enough attention to the P0356 code. While maintenance may be beneficial for the vehicle, it does not investigate the root of the problem associated with the P0356 code. A complete diagnosis is required to accurately identify and correct this problem(s).

How serious is the fault code? P0356?

Problems associated with the P0356 code are not safety critical, but if not detected and corrected promptly, they can lead to more costly repairs, especially if the engine is not running efficiently, requiring additional maintenance costs.

What repair will help eliminate the code? P0356?

Typically the repairs needed to resolve this code are quite simple. This may include one of the following:

1. Replacement or repair of the ignition coil.
2. Replace or repair the wire in the ignition coil driver circuit if there is a short circuit or break.
3. Clean, repair or replace the connector if it is damaged by corrosion.

What is P0356 Engine Code [Quick Guide]

P0356 – Brand-specific information

Code P0356 for the top 6 popular car brands in the world:

1. Toyota P0356: Ignition Coil Primary/Secondary Circuit Problems for Toyota.
2. Ford P0356: Ignition Coil Primary/Secondary Circuit Malfunction for Ford.
3. Honda P0356: Ignition Coil Primary/Secondary Circuit Problems for Honda.
4. Chevrolet P0356: Ignition Coil Primary/Secondary Circuit Malfunction for Chevrolet.
5. Volkswagen P0356: Problems with the primary/secondary circuit of the ignition coil for Volkswagen.
6. Nissan P0356: Ignition Coil Primary/Secondary Circuit Malfunction for Nissan.