P0506 CODE: Idle Air Control System RPM Lower Than Expected

Of all the error codes a car owner will encounter, the p0506 code is among the most common. What does it mean? Is it possible to get it fixed on your own? Let me tell you more about this code and what you can do to get rid of it in this post.

What Does the Code P0506 Mean?

The error code P0506 can be defined as the “Idle Air Control System RPM Lower than Expected”. Meaning, the RPM or revolution per minute of an inactive control system is below the standard. This issue is often the result of the damaged idle air control engine & vacuum leaks, leading to power loss and decreased engine performance.

The P0506 is classified as a universal trouble code. It means the code applies to all cars that have the OBD-II system, especially those models crafted from 1996 to present. The specs in troubleshooting, definition, and repairs will differ from one brand or unit to another.

Also Read: Bad Idle Air Control Valve Symptoms and Bad TPS Symptoms

This particular error code will mean the PCM has diagnosed that the engine’s idle speed is below then the default RPM. It is widely found on the cars that have electric throttle control. These vehicles do not have the standard throttle wire to the motor from an accelerator pedal. Instead, they rely on the electronics and sensors in controlling the throttle.

Causes of the Diagnostic Code P0506

This code can appear as a result of the following factors:

  • Vacuum leakages
  • Malfunctioned indolent air control engine
  • Dirty or malfunctioned throttle body
  • Damaged power steering strain switch
  • Clogging in the exhaust or air intake
  • An issue with the interior motor component
  • Broken PCV valve
  • Defective PCM

  • Signs and Indicators of the Code P0506

    You can tell your car is experiencing this issue with the following indicators:

  • Decreased motor idle speed
  • The check motor light indicator turns on
  • Rough motor idle
  • Erratic idling
  • The motor stalls when your car stops
  • Idle Air Control System RPM Higher Than Expected

    P0507 CODE

    Is the Code P0506 a Serious Problem?

    This trouble code can trigger power loss that you may experience while you drive. It can make driving more dangerous than it is. Therefore, it has been considered as something serious and must be fixed as soon as possible. Diagnosis & repair must be taken properly and immediately.

    How to Check?

    Like other error codes, I will diagnose the issue by using the OBD-II scanner. With this, I gather all of the codes that exist within the PCM and confirm. After that, I will check the stoppage frame information to identify the scenarios when the code has been created. From there, I will clear this code and have your car undergo the test drive to replicate the scenarios to find out if the code returns.

    I will then use my OBD-II scanner in viewing the statistics stream to compare the recent motor idle RPM with the default RPM. It will also test the motor idle RPM. I will turn on the AC and the heater blower engine. During this phase, I will place the motor under different loads and find out whether the PCM is maintaining the standard motor idle speed or not.

    The next step will be checking the entire throttle body to detect the vacuum leakage signs and increased carbon buildup. In case I detected increased carbon buildup, throttle body cleaning is necessary. Moreover, checking the live information provided by the OBD-II scanner is a must to determine if both the PCM and idle air switch systems are in good condition.

    How to Repair the Code P0506?

    Every auto mechanic can fix this issue in many ways. Of course, a comprehensive diagnosis is important to identify the actual cause. The common actions to take in repairing this issue are:

  • Vacuum leaks replacement
  • Damaged indolent air control engine replacement
  • Indolent air control regulator replacement
  • Throttle body cleaning
  • Damaged throttle body replacement
  • Removing the clogging in the air intake or exhaust
  • Broken PCV valve replacement
  • Power steering strain switch replacement
  • Diagnosis & repair for other codes saved in PCM
  • PCM reprogramming or replacement
  • The code P0506 triggers the motor to lose its power that can be damaging. In other instances, the PCM stores more codes aside from the P0506. The codes should be checked and fixed properly to get rid of misdiagnosis.

    Likewise, the code P0506 is the result of the vacuum leaks or carbon buildup. These components need checking.


    The code P0506 is a great issue that you should try to fix as soon as possible. If you think you can’t fix the issue with the steps and instructions I gave, then entrusting the job to a reputable mechanic will be the best thing to do. Feel free to seek help from the near car repair shop once you encounter this issue for assistance and extra tips to avoid encountering the same issue in the future.

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