P0508 Code: Idle Air Control Circuit Low

If you’re planning to fix your vehicle on your own, you’ll need to follow the recommended diagnostic and repair procedures to keep your vehicle in good condition.

What Does the P0508 Code Mean? 

The P0508 code is defined as “Idle Air Control Circuit Low.” It’s a generic powertrain trouble code that applies to vehicles with OBD-II, which includes most vehicles made in 1996 and beyond up until the electronic throttle body became prevalent in the 2000s.

The idle air control (IAC) system consists of an actuator that either uses a stepper motor or a variable force current or pulse width controlled solenoid. Code P0508 indicates an issue the ECM/PCM has detected with at least one electrical wiring circuit or within the actuator itself.

An illuminated check engine light and a stored P0508 code might mean that your powertrain control module (PCM) has detected a problem with the intake air control (IAC) circuit. The IAC system has parts that are designed to regulate the amount of air entering the intake manifold. If there isn’t enough air entering the engine through the throttle body, your engine may stall. You may get a P0508 code if your engine’s RPM levels don’t meet programmed limitations (e.g. if your vehicle idles at an unusually high RPM or stalls).

A detailed understanding of idle air control systems can help you better understand P0508, especially if you’re planning to diagnose and fix it yourself. Read our technical discussion about IAC systems for more information.

Note: The definition of code P0508 may be different depending on the vehicle manufacturer. Consult the appropriate repair manual or repair database for the exact code definition.

What are the Common Causes of the P0508 Code?

There are several possible causes for a P0508. Here are the most commonly reported ones:

• Faulty IAC motor or valve 
• Leak in engine vacuum 
• Open or shorted IAC control wiring or connectors
• Carbon buildup in the throttle body or IAC valve 
• Malfunctioning PCM or PCM programming error

What are the Common Symptoms of the P0508 Code?

A P0508 code might share similar symptoms with related idle air control circuit trouble codes like P0509, P0511, P0518, and P0519. You’ll have to pay close attention to your vehicle’s symptoms to make sure. We’ve compiled the most common symptoms for this code to help you diagnose the problem.

• Idling at a high engine RPM
• Engine frequently stalls while idling
• Noises coming from the throttle body
• Other IAC related codes

How to Diagnose the P0508 Code

A P0508 code can cause problems for your vehicle if it isn’t addressed. The following video shows the general diagnostic procedure for troubleshooting a P0508 code. We suggest looking up some technical bulletins or repair manuals for your vehicle before attempting any sort of fix.

How to Fix the P0508 Code

Several factors can trigger a P0508 code, which can make the repair process confusing for those who don’t have the required auto repair knowledge and expertise. 

If you still want to perform the repairs on your own, you could start by checking your vehicle’s repair manual. You might also find the information you need from repair manuals, like those from Chilton. We also highly recommend an ALLDATA single-vehicle subscription for beginner DIYers because it contains detailed instructions and diagrams. 

After gathering all the information you need, you’ll have to find the underlying causes of your DTC to figure out the next steps. Don’t assume that a P0508 code means you have a bad IAC part. You might have a faulty PCM or bad connectors. Make sure to thoroughly check your IAC system and PCM to pinpoint the problem that’s causing your DTC.

Get High-Quality Idle Control Valves For Your Car

Resolving the P0508 code requires tracking down the part responsible for the trouble code. Whether it’s the idle control valve or something else, replace it as soon as possible to avoid additional costly issues. For high-quality replacement idle control valves, order here at CarParts.com.

CarParts.com offers world-class parts and accessories at competitive prices. Our product catalog includes idle air control valves for various makes and models. We speed up the process of finding the right part for your vehicle and budget. Plug your vehicle’s details into our website’s built-in vehicle selector and browse the results. Do you have any questions about our products? Our helpful customer service team is on hand 24/7 to assist you in choosing the right product.

Why leave your home to purchase replacement idle control valves when CarParts.com delivers to your doorstep? Order before noon ET and get your new idle control valve shipped in several business days if you live in the continental US.