The Idle Air Control System is responsible for maintaining and regulating your vehicle engine speed at rest. When one of the components of this system fails or goes bad, your check engine light will turn on. The use of an OBDII scan tool can quickly help you root cause the issue. Should the error come back as a P0506 trouble code, you can clear your check engine light with a few steps.
This is not to be confused with a similar OBDII code, P0505 – Idle Air Control System although the P0506 code can exist at the same time. The difference is that issues with the idle air control system are different than the P0506 low RPM issue.
What does the OBDII P0506 code mean?
This OBDII trouble code translates to Idle Control System RPM lower than expected. This means that for whatever reason, your idle is lower than what your Powertrain Control Module expects, and it can cause serious driving issues.
As you drive your vehicle, there are different loads and situations that your PCM / ECU must deal with. When there’s a leak or failure of your idle system, it makes it difficult to maintain a proper idle. This is when your check engine light will turn on, signifying a P0506 trouble code.
The OBDII code P0506 will trigger your MIL when your vehicle idle is lower than the pre-determined RPM level for a specified amount of time.
Symptoms of P0506
- idle is very low
- Vehicle cannot maintain idle when cold
- Rough idle
- Inconsistent idle
- Car will die at stop lights
What causes P0506 error code?
As we have covered previously there are many components to your idle air control system. Any number of these can cause serious issues when it comes to your check engine light turning on.
Here are just a few of the common P0506 causes below :
Bad Idle Air Control Motor – This stepper motor is a simple device that slowly allows air to enter the intake manifold. Often placed nearby the throttle body, this motor or valve can fail to create a lack of idle control.
Unfortunately in some cases, this motor is not modular. This means you must either replace the throttle body or in some extreme cases the entire intake manifold or plenum.
Vacuum leaks – Like any air bypass system, leaks can seriously mess with your ECU’s ability to dictate events properly. Cracks in vacuum lines or broken valves, faulty connections can all contribute to this issue. Take the time to properly pressure test your intake system to eliminate the chance of vacuum leaks.
Carbon buildup – Over time carbon can buildup in your throttle body or intake manifold. This can severely impact your idle control system and prevents air from bypassing your throttle body. When this happens, your ECU and idle control system simply can’t keep up, triggering the P0508 error code.
How can I troubleshoot P0506?
Before you go about trying to fix P0506 issues, you should understand what kind of throttle system your vehicle uses. For most vehicles before the 2001 model year, they use a traditional cable-driven throttle body system. This is a fairly easy system to troubleshoot.
There is a traditional wire connected from, your accelerator pedal to your throttle body. In this design and idle control system, there’s typically a bypass that allows air to enter the intake manifold directly.
For late-model vehicles manufactured after 2001, the cable-driven throttle is done away with. Instead the drive-by-wire system incorporates the idle control system into the electronic throttle body.
Start by testing your air idle control valve, or inspecting the real-time values from your electronic throttle body. Want to learn more about idle air control controllers or OBDII trouble codes in relation to your idle? Subscribe to My Pro Street for all the latest tech tips and DIY articles.