P0506 — Idle air control system RPM lower than expected
Idle is lower than the computer wants — sticky throttle body, vacuum leak, or idle control issues are common themes.
What it means in plain English
P0506 means measured idle speed is below the target. Causes include a dirty throttle body, vacuum leaks, failed idle air control (on older designs), or induction issues. Companion codes help narrow it.
Common causes
- Carbon on the throttle body
- Vacuum leak
- Idle control / electronic throttle adaptation issues
- Air leaks after the MAF
What you can safely check
- Note stalling at stops or rough idle.
- Throttle-body cleaning can help — but follow a procedure that won’t damage coatings or require relearn steps your car needs.
Pull the code yourself (disclosed)
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A reusable Bluetooth OBD-II scanner lets you read the code and freeze-frame data before authorizing “mystery” diagnostics. One option: BlueDriver Bluetooth Pro OBD-II scan tool (BlueDriver/Levanta affiliate). Any capable OBD-II reader is fine — this is not required to use Fair Auto Shops.
When to go to a shop
Ask about throttle relearn procedures after cleaning or parts. Electronic throttles aren’t always “spray and go.”
Typical related repair costs
Idle repairs vary widely by design; we omit a single national parts price here because the failed part isn’t unique. Get a written diagnosis first.
Questions to ask before you authorize work
Use questions before you authorize a repair and how to read a repair estimate. Watch for patterns in spotting upselling.
Find an honest independent shop
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FAQ
What should I do first with a P0506 code?
Photograph all codes, note symptoms and whether the light is flashing, avoid clearing data until a shop sees it, then use an independent shop with a clear diagnostic plan.
More check-engine codes
P0420 · P0430 · P0300 · P0301 · P0171 · P0174 · P0455 · P0456 · P0442 · P0446 · P0128 · P0401 · P0133 · P0113 · P0507 · P0700 · P0741 · P0011 · P0325 · P0340 · P0335 · P0101 · P0299 · P0135 · P0440 · P0441 · P0010 · P0500 · P0121
Hub: How to read a check-engine code · Repair cost guides · Affiliate disclosure