P021C Fault Code

P021C OBD-II Trouble Code Short Description

Cylinder 9 Injection Timing

What does trouble code P021C mean?

The P021C fault code is related to the turbocharger boost control module's performance. It indicates that the module has detected a malfunction in the boost control system, leading to engine performance issues.

The reason for such a fault code is often due to a faulty turbocharger actuator or a failure in the boost controller's electrical circuit. The actuator may be stuck in a particular position, preventing it from adjusting the turbo's output effectively. Electrical problems such as corroded wiring or damaged connectors can also cause the fault code to appear.

To fix the issue, a mechanic will first diagnose the fault's underlying cause by performing a series of tests on the boost control system. They may use specialized tools to check sensor readings and wiring continuity. After identifying the issue, they will repair or replace the faulty component as needed.

Ignoring a P021C fault code can lead to reduced engine performance, increased emissions, and even engine damage in severe cases. If you notice the warning light on your dashboard, it's best to take your car to a professional for diagnosis and repair as soon as possible.


What are the symptoms of the P021C code?

Symptoms of P021C fault code on cars can include:

  1. Check engine light illuminating on the dashboard
  2. Reduced engine power
  3. Engine stalling or dying
  4. Difficulty starting the engine
  5. Rough idling or running
  6. Poor acceleration
  7. Decreased fuel efficiency
  8. Emission control system failures
  9. Transmission shifting issues.


What causes the P021C code?

The P021C fault code is related to the engine control module (ECM) and refers to a problem with the Fuel Injector Control Circuit. Some common causes of this fault code include issues with the fuel injection system, damaged or faulty fuel injectors, and wiring problems within the injector circuit. In some cases, the problem may also be due to a malfunctioning ECM or other related components. Proper diagnosi

Possible Solutions

How to fix P021C?

To fix the P021C fault code on your car, follow these steps:

  1. Check the wiring and connectors: Start by checking the wiring and connectors related to the fuel injection system. Make sure that all wires are properly connected and free of any damage.

  2. Check for vacuum leaks: Vacuum leaks can cause this fault code, so check for any leaks in the vacuum system. You can use a vacuum gauge to determine if there are any leaks.

  3. Check the fuel pressure: Low fuel pressure can also cause the P021C fault code. Check the fuel pressure using a fuel pressure gauge. If the pressure is low, you may need to replace the fuel pump.

  4. Check the fuel injectors: Faulty fuel injectors can also cause this fault code. Check the fuel injectors using a multimeter. If any injectors are faulty, replace them.

  5. Check the fuel rail pressure sensor: The fuel rail pressure sensor can also cause the P021C fault code. Check the sensor using a multimeter. If it is faulty, replace it.

  6. Check the fuel filter: A clogged fuel filter can also cause this fault code. Check the fuel filter and replace it if necessary.

By following these steps, you can fix the P021C fault code on your car and ensure that your engine is running smoothly.


  • What is P021C?

    P021C is a Diagnostic Trouble Code (DTC) that indicates an issue with the Engine Control Module's (ECM) fuel injector control circuit for cylinder 3 of the engine.

  • What causes the P021C code?

    The P021C code is typically caused by a faulty fuel injector, damaged wiring or connectors in the fuel injector circuit, or a malfunctioning ECM.

  • What are the symptoms of a P021C code?

    The symptoms of a P021C code may include poor engine performance, reduced fuel efficiency, engine misfires, and increased exhaust emissions.

  • How is a P021C code diagnosed?

    The P021C code is diagnosed using an OBD-II scanner, which retrieves the code and its associated freeze frame data. A visual inspection of the fuel injector circuit may also be performed to identify any obvious issues.

  • How is a P021C code repaired?

    The repair for a P021C code typically involves identifying the underlying cause of the issue and replacing or repairing the relevant component. This may include replacing a faulty fuel injector, repairing damaged wiring or connectors, or replacing the ECM.

  • Can a P021C code be ignored?

    It is not recommended to ignore a P021C code, as it may lead to further engine damage or reduced performance. It should be diagnosed and repaired as soon as possible.

  • What is the cost to repair a P021C code?

    The cost to repair a P021C code can vary depending on the underlying cause of the issue and the cost of replacement parts or labor. It may range from a few hundred to several thousand dollars.

  • Can a P021C code be prevented?

    Prevention of a P021C code may include regular engine maintenance, including fuel system cleaning and replacing fuel filters as recommended by the manufacturer. Properly maintaining the fuel injector circuit and ensuring that all wiring and connectors are in good condition may also help prevent this issue from occurring.