P0350 Ignition coil primary/secondary circuit malfunction
OBD2 Error Codes

P0350 Ignition coil primary/secondary circuit malfunction

21.09.2023 /

P0350 – OBD-II Trouble Code Technical Description

Ignition coil primary/secondary circuit malfunction

What does the fault code mean P0350?

Trouble code P0350 is a common code for vehicles that support OBD-II (such as Hyundai, Toyota, Chevy, Ford, Dodge, Chrysler and others). It indicates problems with the primary and/or secondary circuits of the ignition coils or ignition coil assemblies. Most of these vehicles use an ignition system with individual ignition coils for each cylinder. These coils create sparks to ignite the spark plugs. The ignition system is monitored and controlled by the PCM (engine control module).

If a malfunction occurs in one of the ignition coil circuits, the PCM will set a P0350 code, which may cause the engine to not operate properly. The ignition system plays a key role in engine performance, so it is important to identify and correct such problems promptly to ensure reliable vehicle operation.

Possible reasons

The P0350 code is activated when the voltage recorded by the vehicle's computer is very different from the manufacturer's default settings, exceeding 10%. This problem can occur due to a faulty or damaged ignition coil, broken or corroded wiring, improperly connected connectors, or a faulty PCM (engine control module).

Possible causes of this malfunction include problems with the primary or secondary circuits of the ignition coils, lack of contact in the electrical connections of the ignition coils, or even a malfunction of the PCM itself. These problems can cause the ignition system to malfunction and therefore cause the engine to not function properly.

What are the symptoms of a fault code? P0350?

The P0350 misfire code can be a serious problem and its symptoms include:

  1. Driveability problems such as misfires.
  2. Incorrect engine operation.
  3. Deterioration in fuel efficiency.
  4. Possible occurrence of other misfire codes such as P0301, P0302, P0303, P0304 and so on.

This code may also be accompanied by an illuminated check engine light, loss of power, difficulty starting the engine, hesitant idle, and problems stopping the engine. It can significantly affect engine performance and requires diagnostics to correct the problem.

How to diagnose a fault code P0350?

To diagnose a P0350 code, first check the circuits between the PCM and the ignition coils, as well as the ignition coils themselves. Signs of disconnected ignition coils can be found by shaking them and checking to see if they move. This code is often associated with electrical problems, so check the wiring and connectors carefully. If the coils and wiring are ok, then the PCM may be faulty.

To diagnose a P0350 code, you will need a diagnostic scan tool, a digital volt/ohm meter (DVOM), and your vehicle's information. The first step is to visually inspect the wiring and connectors of the ignition coils/units. Check for broken connectors or damaged or corroded wiring. Record stored codes and freeze frame data, then clear the codes and take it for a test drive.

To determine which coil/unit is faulty, a method can be used with an assistant applying the brake and accelerator to discover which coil is not affecting engine speed. After this, use the DVOM to check the battery voltage at the coil/block connector with the ignition on. If there is no voltage, check the fuses and relays. If everything is OK, check the circuits for continuity and resistance. Lastly, check for a ground pulse from the PCM at the coil connector.

Please note that a technical tune-up will not solve the P0350 code, and be careful when working with a high-intensity spark near flammable liquids.

Diagnostic errors

Errors when diagnosing a P0350 code may include:

  1. Insufficient check of ignition coil wiring and connectors.
  2. Unaccounted for broken connectors or damaged electrical wiring.
  3. Failure to follow the manufacturer's recommendations when testing circuits and components.
  4. Failure to thoroughly check for ground pulse from PCM.
  5. Unaccounted for problems with other ignition codes that may accompany P0350.

For an accurate diagnosis, you should carefully check all these aspects and carry out the necessary tests.

How serious is the fault code? P0350?

Although a vehicle with a P0350 code can continue to drive, it can severely affect its handling, especially in stalling and accelerating situations. Since this error may cause the engine to shut down, it is recommended to carry out repairs as soon as possible to ensure safe driving.

What repair will help eliminate the code? P0350?

If any components related to the ignition coil system (including the PCM) are found to be faulty, it is important to repair or replace them as required. If problems are found with the wiring or connectors, it is necessary to restore continuity between the PCM and the faulty ignition coil or replace the damaged components. After each individual repair, it is recommended to recheck the ignition system to ensure that the source of the malfunction has been eliminated.

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P0350 – Brand-specific information

P0350 codes by car make:

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