P0506: Idle Air Control (IAC) System RPM Lower Than Expected

What Does The P0506 Code Mean?

This P0506 code is one that’s sometimes triggered on vehicles that have electronic throttle control. That is, they don’t have a regular throttle cable from the accelerator pedal to the engine. They rely on sensors and electronics to control the throttle.

In this case, the P0506 DTC (diagnostic trouble code) is triggered when the PCM (powertrain control module) detects an engine idle speed that is lower than the desired (pre-programmed) RPM.

What Are The Symptoms Of The P0506 Code?

Most likely the only thing you’ll notice is the idle speed is lower than normal so it will likely be rougher. There are potentially other symptoms as well.

Of course, when trouble codes are set, the MIL (malfunction indicator lamp, a.k.a. the check engine light) illuminates.

What Are The Potential Causes Of The P0506 Code?

A P0506 DTC trouble code may be caused by one or more of the following:

• A vacuum leak
• An air restriction in the intake air path or exhuast
• A faulty positive crankcase ventilation (PCV) valve
• Damaged/failed/dirty throttle body
• Internal engine problem
• Failed PCM

How Can You Fix The P0506 Code?

This DTC is more of an informational code, so if there are any other codes set, diagnose them first. If there are no other codes, inspect for vacuum leaks, restrictions, and damage. If there are no symptoms other than the DTC itself, just clear the code and see whether it returns.

Other related DTCs: P0505, P0507

Recommended Parts

Below are some recommended auto parts to help you address the trouble code affecting your vehicle and get it running smoothly again:

>>> EGR Valve
>>> PCV Valve
>>> Throttle Body (generic)
>>> WORKPRO 582-piece Crimp Terminals, Wire Connectors, Heat Shrink Tube, Electrical Repair Kit
>>> Dorman 86689C 399 PC Automotive Electrical Repair Kit

Note: During the purchasing process, please check carefully whether the part you want to buy fits your car!

Check This Video For Reference

Reference Sources

Diagnostic Trouble Code (DTC) Charts and Descriptions for P0506 – Pages 80-81.