Trouble Code P0506: Idle Air Control System RPM Lower Than Expected

The idle system is one of the most vital elements of your vehicle. The vehicle idle system helps in maintaining the working of your car in its idle state and keeps it safe from blocking or stalling, most importantly when the high-power consuming components (AC, radiator) of your car are running. Due to the fault in your car’s idle control system, many OBD-II trouble codes may trigger. The code P0506 is the usual trouble that may trigger due to multiple causes. This mainly explains the causes, meaning, symptoms, and how to fix the P0506 code.

What Does the P0506 Code Mean?

Every Diagnostic Trouble Code (DTC) refers to specific trouble in your car. The code P0506 means that the RPM of the Idle Air Control System is less than the desired RPM.

The powertrain control module (PCM) of the car sends the P0506 code to the car dashboard to indicate that the engine idle control system’s revolution per minute (RPM) is lower than expected.

P0506 code

Usually, cars with a separate idle air control (IAC) valve or Electronic Throttle Control (ETC) experience the P0506 frequently. To regulate the idle RPM of your car, IAC adjusts some air that evades the throttle blade of the car.

Alternatively, the Throttle cable and IAC valve are not present in the vehicles with Electronic Throttle Control (ETC). Therefore, these vehicles depend on the electronic motor to regulate the idle RPM and control the throttle.

Your vehicle may trigger other codes (such as P0012, P0013, P0016, or P0017) along with P0506. However, there are multiple causes of the P0506 code. Therefore, you must properly find and fix the cause on time before the RPM of the engine at an idle state matches its normal SPM. To fix this code properly, you must drive your vehicle to a mechanic and ask him to fix it.  

Causes of Code P0506

Several primary problems may trigger the diagnostic trouble code P0506. Having a clear understanding of these potential problems may drastically reduce the amount of time needed for diagnostics and repairs, allowing you to get your car back on the road quickly.

The following are the common causes of the P0506 code:

  • The damaged Idle Air Control (IAC) valve
  • The damaged or broken Powertrain Control Module (PCM)
  • Faulty Positive Crankcase Ventilation (PCV) valve
  • Fault in Electronic Throttle Control (ETC) system
  • Damaged wires or bad circuit connections
  • The clogged intake and exhaust valves
  • Defective or contaminated throttle body
  • The issue with the power steering pressure switch
  • Vacuum leaks

Symptoms of Trouble Code P0506

As the PCM of your car detects the P0506 code, it sends the signal to the check engine light, which starts illuminating. However, your check engine light may illuminate due to multiple causes. Therefore, it is difficult to say which part is facing fault. After the proper diagnosis and scanning through the OBD scanner, you can get to know the trouble code and the exact core issue.

Symptoms of Code P0506

Here are common symptoms your car may show if it has trouble code P0505:

  • Rough engine idle
  • Engine stalling as your car approaches to halt
  • Illuminated Check Engine Light
  • Uncommon idling states
  • Low idle speed of the engine 

How to diagnose the P0506 code?

Follow the below-given steps to diagnose the P0506:

  • Scan all the trouble codes from the PCM of the car through the OBD-II scanner.
  • Examine the freeze frame data to analyze the status of the engine at the setting time of the trouble code.
  • Clear the codes and take a test drive to check whether the codes come back.
  • The technician will inspect the data stream on the OBD-II scanner and match the engine’s current idle RPM with the manufacturer’s pre-set idle RPM settings.
  • Now, they will turn on the air conditioner and heater blower to test the engine idle RPM. During this phase of the diagnostic procedure, the engine will be subjected to a variety of loads to see whether the PCM can sustain a typical engine idle speed.
  • Test for vacuum leaks and high carbon buildup in the throttle body. In case of high carbon buildup, clean the entire throttle body.
  • To check the proper functionality of the PCM and IAC, use the live data on the OBD-II scanner.

How to Fix P0506 Code

Follow the below-given steps to fix the P0506 code:

How to Fix Code P0506

  • Before the proper diagnostic of P0506, always search for all trouble codes and diagnose them thoroughly.
  • Check the damaged wiring between your car’s engine’s air filter housing and throttle body.
  • Check if the air filter needs replacement. If yes, replace it.   
  • Examine your car’s engine throttle body and see if you find any evidence of high-carbon fouling. Now, clean the fouling with the proper solvent and a nylon brush.
  • Examine the electrical harness for the throttle body.
  • Test the serious vacuum leaks. They can be tested using different methods, but the smoke machine is one of the most effective tests for this purpose.
  • If no issue has emerged up to this point, freeze frame data about the trouble code should be examined. You may accomplish this with practically any good and contemporary scan tool.

P0506 Repair Cost

The repair cost of P0506 varies according to the nature of the damage. For example, the cost of throttle body cleaning is from $230 to $310. However, the replacement cost of a bad IAC valve is from $140 to $510.

FAQ Section

What is meant by Trouble code P0506?

P0506 means that your car is not idling efficiently, and idle speed is quite lower than the expected RPM. The latest vehicles have ETC to calculate the idle speed of the engine. As you see this trouble code, it means you have a faulty electronic throttle control (ECT).

How serious is the Code P0506?

The code P0506 is typically considered highly significant because it can impact an engine’s capacity to run as designed.

The engine of a vehicle is intended to idle at a certain RPM range without faltering or stalling. This fault may cause bogus functional parameters.

In an intense situation, the car may stall while going to stop. Hence it is a little risky to drive the car while your car is showing P0506.

Is it safe to drive with the P0506 code?

Sometimes, due to P0506, your car power may lose while driving, and this loss of power may cause some crucial driving conditions. That is why code P0506 is referred to as a serious one. It is recommended to diagnose and fix this code as early as possible.

What repairs can fix the P0506 code?

  1. Inspect the IAC motor and replace it if needed
  2. Replace the defective PCV valve
  3. Repair the vacuum leaks
  4. Diagnosing and repairing any other codes that have been stored by the PCM
  5. Replace or clean the air intake and exhaust valves
  6. Replace the IAC valve
  7. Clean dirty throttle body
  8. Replace or reprogram the powertrain control module (PCM)
  9. Replacing the power steering pressure switch
  10. Replace defective throttle body

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