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P0084 Code – What Does It Mean & How To Fix It

This is one of the most frequent OBD2 trouble codes. Read the full article below to know what it means, how to fix it, and what other codes may show related to it.


The exhaust valve control solenoid circuit for Bank 1 is having difficulty according to the OBD-II fault code P0084, which is a Diagnostic Trouble Code (DTC). This code primarily relates to a low-voltage issue with the solenoid that controls the exhaust valve.


If a P0084 code is detected, it indicates the solenoid to control Bank 1's exhaust valve has some kind of low voltage condition. In order to ensure optimal performance and emissions control, the exhaust valve solenoid shall play a major role in regulating air flow from the engine.


The P0084 DTC code may have a number of possible reasons, including:

  • Faulty exhaust valve control solenoid: The solenoid may have internal electrical faults or be stuck in the closed position, resulting in a low voltage condition.
  • Wiring or connection issues: Corroded terminals, damaged wiring, or loose connections can all affect the electrical circuit and result in low voltage.
  • Faulty engine control module (ECM): A malfunctioning ECM can send incorrect signals or fail to supply sufficient voltage to the solenoid.
  • Short to power or ground: In the exhaust valve control solenoid circuit, a short circuit to power or ground might result in a low voltage problem.


The P0084 code may also be accompanied by a number of typical symptoms, such as:

  • Check Engine Light (CEL) On: The most glaring indication of a problem is the illumination of the CEL on the dashboard of the car.
  • Reduced engine performance: The car's overall performance and power may be affected.
  • Low fuel efficiency: The reduced airflow brought on by the low voltage situation might result in worse fuel efficiency.
  • Rough idling: The engine may run unevenly or exhibit irregular idle speed.


It is advised to carry out the following actions in order to correctly diagnose the P0084 code:

  • OBD-II scanner: Use an OBD-II scanner to retrieve the specific code and any related codes.
  • Visual inspection: Conduct a thorough inspection of the exhaust valve control solenoid, wiring, and connectors to identify any visible issues or damage.
  • Testing the exhaust valve control solenoid: Use a multimeter to measure the resistance and voltage of the solenoid.
  • Inspecting the wiring and connections: Check for damaged wiring, loose connections, or corroded terminals.
  • Testing the ECM: If required, run tests to ensure the ECM is operational.

Common mistakes

The following typical errors should be avoided while diagnosing and fixing the P0084 code:

  • Ignoring pertinent codes: Examine and fix any further relevant codes that may be a factor in the problem.
  • Insufficient visual examination: Make sure you do a complete inspection of the wiring, connections, and other parts for any obvious issues.
  • Failing to address root causes: Simply clearing the code without resolving the underlying issue can lead to recurring problems.

How serious is this?

Depending on the vehicle and its specific circumstances, the severity of the P0084 code may differ. It is not recommended to ignore this issue, since the vehicle can still be operated. Damage to the engine, reduced performance, and increased emissions may result from the prolonged operation of a defective exhaust valve control solenoid.

What repairs can fix the code?

Repair manuals

It could be essential to make the following repairs to fix the P0084 error code:

  • Replacing the exhaust valve control solenoid: If the solenoid is faulty or stuck in the closed position, it should be replaced.
  • Repairing or replacing damaged wiring or connectors: Any issues with the wiring or connections must be addressed.
  • Checking for short circuits: Inspect the exhaust valve control solenoid circuit for any short circuits to power or ground and repair them as necessary.
  • ECM replacement or repair: If the ECM isn't working properly, it may need to be fixed.

Related codes

Some related codes that may be associated with the P0084 DTC code include:

  • P0075: Intake Valve Control Solenoid Circuit Bank 1
  • P0076: Intake Valve Control Solenoid Circuit Low Bank 1
  • P0077: Intake Valve Control Solenoid Circuit High Bank 1
  • P0082: Intake Valve Control Solenoid Circuit High Bank 2


The P0084 DTC code indicates a low voltage condition in the solenoid control circuit of the exhaust valve for Bank 1. In order to avoid any further engine damage and maintain optimal vehicle performance, it is essential that this code be dealt with as soon as possible. 

You can correct the problem and get your car back to working order by accurately diagnosing it and carrying out the necessary repairs. If the P0084 DTC Code is to be properly diagnosed and repaired, you must first contact an experienced technician.

P0084 code – what does it mean & how to fix it