What does P0506 mean?

The engine idles slower than the ECU's target.

Can a dirty throttle body cause P0506?

Yes, it is one of the most common causes.

Speed and idle control

P0506 — Idle Control System RPM Lower Than Expected

The engine idle speed is lower than the target the ECU sets. The engine may idle roughly or stall.

Severity: Low

Common causes

Dirty throttle body or idle air passages
Faulty idle air control valve
Vacuum leak (less common for low idle)
Clogged air filter or restricted intake
Heavy load such as a worn A/C compressor or alternator

Symptoms

Low or rough idle
Stalling when stopping
Surging
Check engine light

How to check

Clean the throttle body and idle air passages
Check the idle air control valve or electronic throttle response
Check the air filter and intake
Check loads on the engine and fuel trims

Can you keep driving?

Usually drivable, but stalling in traffic is possible. Repair it soon.

Frequently asked questions

What does P0506 mean?: The engine idles slower than the ECU's target.
Can a dirty throttle body cause P0506?: Yes, it is one of the most common causes.

General reference information. It does not replace a diagnosis on your own vehicle. The same code can have different causes depending on make, model year and engine; check the manufacturer's documentation or ask a technician with a scan tool.