Chevy Trailblazer P0506: Idle Air Control – RPM Lower than Expected

P0506 It is the most common OBDII code. This code is usually triggered when engine idle speed falls below the limit pre-determined by the manufacturer.

This is known as a generic code. It has the exact same meaning regardless of whether it's used for another purpose. Chevy Trailblazer As it would for any other vehicle.

 P0506 Symptoms:  Trailblazer

P0506 should be visible when you drive, most of the times. These are some of the symptoms that can be seen in the Trailblazer.

• Coming Soon: Service Engine Light– The reason why you are here.
• Lower idle speed– Assuming that the code has been thrown due to a legitimate issue, you should notice the engine running slower when not pushing the gas.
• Stalling–  The idle may be too slow for the car to run without pressing on the accelerator pedal.

Chevy Trailblazer 0506 Diagnosis and Causes

Many possible causes of P0506 exist. While the code specifically mentions the “Idle Air Control System”, it would be a mistake to just go ahead and replace the idle air control valve without a little due diligence. It’s not always the cause of the code.

These are the top causes of P0506 problems in Chevy Trailblazers. We also have a waist guide to help you troubleshoot. Be aware that model year variations can cause P0506 to occur. Start by searching for the a Leakage of vacuum You can then move forward.

Vacuum Leak

The Trailblazer will idle faster if the vacuum system is leaking. Leakage of the vacuum system causes the combustion chamber's air to become unstable. 

How to find a vehicle vaccum leak (Popular Mechanics, Article)
Find a Vacuum leak in under a minute (2CarPros, YouTube)

Bad things can cause a vacuum leak vacuum hoseThe Take in a lot, EGR SystemOr anywhere air can flow through. It’s not hard to find a vacuum leak though. Use the resources above and you’ll find it in no time.

Valve to control the idle airflow

Modern fuel-injected engines have an idle air control valve. Some engines are not equipped with an idle air control valve. If you have determined that you don’t have a vacuum leak, the IAC is a great second place to troubleshoot P0506.  You can find idle air control valves here Very affordable.

How to diagnose an IAC valve (Autozone Guides)

Throttle Body

The throttle body can be opened and closed millions of times during the lifetime of a car's engine. It can collect dust from all the air passing through it. The vehicle's idle performance can be affected by this grime. When dirty, you’ll often feel the vehicle almost stall before the computer compensates and opens it a little more.

Alternativly, the throttle body may have been damaged and may stop regulating the airflow properly. In this case, the code could be thrown.

Here are some signs your Throttle Body is failing and what to do (Repair Pal)
What to do if your throttle body is dirty or bad? (YouTube auto repair, Youtube).

Blockage of Intake or Exhaust

The idle could drop to P0506 due to a problem with the catalytic convert or the intake manifold. 

Conclusion

This is an extremely serious problem. It is dangerous to drive with an engine that could stall in any moment. We strongly recommend you get your Trailblazer serviced ASAP. We wish you all the best!