[SOLVED] P3421 Code: Fixing Cylinder 3 Exhaust Valve Control Circuit

The P3421 fault code in automobiles indicates a problem with the Cylinder Deactivation Solenoid. The symptom is the Engine Light ON or Service Engine Soon Warning Light.

The cause could be low oil pressure, restricted oil passage, engine mechanical condition, faulty Cylinder Deactivation Solenoid, Cylinder Deactivation Solenoid harness is open or shorted, or Cylinder Deactivation Solenoid circuit poor electrical connection.

The repair importance is high as it affects the engine’s performance.

The repair difficulty is moderate, and the fix involves visually inspecting the related wiring harness and connectors, checking for damaged components, and looking for broken, bent, pushed out, or corroded connector’s pins. The repair time is estimated to be 1.0 hour. It is essential to check the possible causes listed above to interpret the fault code accurately.

Repair Importance Level10.0 (Out of 10)
Estimated Repair TimeApproximately 1.0 hour
Repair Difficulty Level10.0 (Out of 10)

If you notice the Engine Light ON or Service Engine Soon Warning Light, it could be a sign of p3421 fault code. Here are the symptoms to look out for:

  • The P3421 fault code in an automobile can cause several symptoms, including the engine light turning on or the service engine soon warning light appearing.
  • Other symptoms may include a decrease in engine power, rough idling, engine misfires, and poor acceleration.
  • Additionally, the vehicle may experience stalling or hesitation during acceleration, and there may be a noticeable decrease in fuel efficiency.
  • It is important to address these symptoms promptly to prevent further damage to the vehicle and ensure safe driving conditions.

The automobile fault code P3421 can be caused by a variety of factors, including low oil pressure and faulty solenoids.

  • The automobile fault code P3421 can be caused by low oil pressure, restricted oil passage, engine mechanical condition, faulty Cylinder Deactivation Solenoid, Cylinder Deactivation Solenoid harness being open or shorted, and Cylinder Deactivation Solenoid circuit having poor electrical connection.

Below are the possible fixes for the automobile fault code p3421, including inspecting wiring harness and connectors for damage or corrosion.

  • To fix the automobile fault code p3421, you need to check the possible causes listed above.
  • Visually inspect the related wiring harness and connectors for any damage.
  • Look for broken, bent, pushed out, or corroded connector’s pins.
  • This fix will take an estimated repair time of 1.0 hour.

The automobile fault code P3421 can be diagnosed and fixed within an estimated repair time of 1.0 hour. The cost of repair is influenced by the repair time, which is commonly charged between $75 and $150 per hour by most auto repair shops.

Therefore, the total cost of fixing the P3421 fault code will depend on the hourly rate charged by the repair shop and the estimated repair time required to fix the issue.

The P3421 code refers to a problem with the exhaust valve control circuit in cylinder 3.

This code is related to the cylinder deactivation system, which switches the engine to V4 mode under light load conditions. The system deactivates cylinders 1 and 7 on the left bank, and cylinders 4 and 6 on the right bank. Cylinder deactivation is accomplished by not allowing the intake and exhaust valves to open on the selected cylinders by using special valve lifters.

The deactivation lifters contain spring loaded locking pins that connect the internal pin housing of the lifter to the outer housing.

What are the possible causes of the P3421 fault code?

If you see the P3421 fault code with the engine light on, it could be due to low oil pressure, restricted oil passage, engine mechanical condition, faulty cylinder deactivation solenoid, or poor electrical connection in the cylinder deactivation solenoid circuit. To fix it, check the possible causes listed above, visually inspect the related wiring harness and connectors, and look for damaged components or corroded connector pins.

How can I visually inspect the related wiring harness and connectors to fix the P3421 fault code?

To fix the P3421 fault code, start by checking the possible causes listed above. Then, visually inspect the related wiring harness and connectors. Look for damaged components and check for broken, bent, pushed out, or corroded connector’s pins. This will help you identify any issues with the Cylinder Deactivation Solenoid circuit and poor electrical connection.

What are the consequences of ignoring the P3421 fault code?

Ignoring the P3421 fault code, which indicates a problem with the Cylinder Deactivation Solenoid, can lead to serious consequences. The engine light will remain on, indicating a problem with the engine. The cause of the problem could be low oil pressure, restricted oil passage, engine mechanical condition, faulty Cylinder Deactivation Solenoid, or a poor electrical connection. To fix the issue, it is important to visually inspect the related wiring harness and connectors, check for damaged components, and look for broken, bent, pushed out, or corroded connector’s pins.

p3421 error fault code explained

If you see the Engine Light ON or Service Engine Soon Warning Light, it could be due to low oil pressure, restricted oil passage, or a faulty Cylinder Deactivation Solenoid.

Check the possible causes listed above, visually inspect the wiring harness and connectors, and look for damaged components or corroded pins.

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