P0506: Idle Control System RPM Lower Than Expected
Can you still drive? Yes, but the engine may stall at stops or in traffic. Keep RPMs up when stopped and get it fixed promptly to avoid getting stranded.
What Does P0506 Mean?
Code P0506 indicates that the engine idle speed is consistently lower than the target RPM set by the PCM. The PCM attempts to raise idle speed through the idle air control valve or electronic throttle body, but the actual RPM remains below the desired level. This often results in rough or unstable idle.
Need to read your codes?
An OBD-II scanner lets you read and clear diagnostic trouble codes from your vehicle's computer. Most scanners work with any car made after 1996.
Browse OBD-II Scanners on AmazonCommon Causes
- Dirty throttle body
- Vacuum leak in intake system
- Faulty idle air control (IAC) valve
- Carbon buildup on throttle plate
- Intake manifold gasket leak
Symptoms
- Engine idle is too low
- Check engine light on
- Engine stalling at idle
- Rough or unstable idle
- Engine dies when coming to a stop
Diagnostic Steps
- 1Check current idle RPM with a scan tool and compare to target RPM
- 2Inspect and clean the throttle body
- 3Perform a smoke test for vacuum leaks
- 4Test idle air control valve operation
- 5Check for intake manifold gasket leaks
- 6Reset idle learn values after cleaning
Recommended Parts & Tools
throttle body cleaner
idle air control valve
intake manifold gasket
Estimated Repair Cost
| Type | Estimated Cost |
|---|---|
| Total Repair Cost Range | $20 - $400 |
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Frequently Asked Questions
Can I fix P0506 by cleaning the throttle body?
Yes, a dirty throttle body is one of the most common causes of P0506. Cleaning it with throttle body cleaner and resetting the idle learn procedure often resolves the issue.
Why does my car stall at red lights with P0506?
The engine idle speed is too low to keep the engine running, especially when additional loads like A/C or power steering are applied at idle.
Do I need to do an idle relearn after fixing P0506?
Yes, most vehicles require an idle relearn procedure after cleaning the throttle body or replacing the IAC valve. Check your service manual for the specific steps.
Community Fix Reports
Community reports are user-submitted and not verified by Auto AI Buddy. Results may vary.
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