Skip the auto shop - Our mechanics make house calls
  1. Home
  2. Articles
  3. P0519 OBD-II Trouble Code: Idle Air Control System Performance

P0519 OBD-II Trouble Code: Idle Air Control System Performance

Check Engine Light P0519 OBD-II Trouble Code: Idle Air Control System Performance

Diagnostic Trouble Code (DTC): P0519

P0519 code definition

The P0519 trouble code is defined as idle air control system performance.

What the P0519 code means

When a vehicle idles, it still maintains a certain predetermined RPM decided on by the manufacturer. The PCM (Powertrain Control Module) monitors this RPM to ensure it is at the correct level. There is an acceptable range and if the RPM goes above or below it, the PCM will respond by trying to fix it. If it is unable to do so, the P0519 code will be stored.

What causes the P0519 code?

The most common reason for the P0519 code, by far, is the throttle body being carbon coked at the bore. If that is not it, the cause could be:

  • Open or shorted electrical circuits
  • A sizeable vacuum leak
  • A broken idle air control valve

Though it’s rare, if none of the above is responsible for the code, then the PCM could be the problem.

What are the symptoms of the P0519 code?

If the P0519 code has been stored by the vehicle’s PCM, the RPMs should show running high or low when idling; that is literally the thing that causes this code. The Check Engine Light should come on too.

However, the engine may also stall out when driving low speeds and the accelerator isn’t being depressed. The engine may also stall intermittently when the throttle is released.

How does a mechanic diagnose the P0519 code?

The first thing a mechanic will do is use an OBD-II scanner to retrieve all the trouble codes that have been stored by the PCM. Once they know about the P0519 code, they should inspect the connectors and wiring that work with the air control system.

If that doesn’t help, the problem is probably an intermittent one which can be a lot harder to properly diagnose. Ideally, the mechanic may have to use a specific scanner program that will take them through the IAC system test necessary to proceed with the diagnosis.

Otherwise, the mechanic may simply have to let the problem get worse before they do another inspection to find the source of the problem.

Common mistakes when diagnosing the P0519 code

One common mistake a lot of mechanics make once they know a P0519 code has been stored is immediately replacing the idle air control part. What they should do is clean off the throttle body bore first. Otherwise, there’s a good chance of a misdiagnosis occurring.

How serious is the P0519 code?

Even if it just seems like a small problem at first, it won’t be long before the P0519 problem begins making it difficult to drive. It’s not necessarily a dangerous problem, but the engine can suddenly idle while on the road. This will continue to happen until repairs are done.

Furthermore, as we touched on above, this problem can grow into something much worse if it isn’t caught early and properly diagnosed.

What repairs can fix the P0519 code?

A lot of the time, all it takes is simply cleaning off the throttle bore body or the wiring and connectors the air control system needs to work properly. As we mentioned above, the most common reason for the code being triggered is the throttle body being carbon coked, so the “repair” may call for nothing more than a thorough cleaning of this component.

Other times, it could be that there is a large vacuum leak, which will most likely call for a replacement. If the idle air control valve is broken, that will either need to be repaired or replaced.

Additional comments for consideration regarding the P0519 code

Unfortunately, if there’s no clear source for the problem, and the PCM has been checked to make sure it is working correctly, the driver will simply need to put up with the issue a while longer until the cause makes itself known.

Need help with a P0519 code?

YourMechanic offers certified mobile mechanics who will come to your home or office to diagnose and repair your vehicle. Get a quote and book an appointment online or speak to a service advisor at 1-800-701-6230.

The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details
Icon-warranty_badge-02

Skip the repair shop, our top-rated mechanics come to you.

At your home or office

Choose from 600+ repair, maintenance & diagnostic services. Our top-rated mechanics bring all parts & tools to your location.

Fair & transparent pricing

See labor & parts costs upfront, so you can book with confidence.

12-month, 12,000-mile warranty

Our services are backed by a 12-month, 12,000-mile warranty for your peace of mind.

Get A Quote

Need Help With Your Car?

Our certified mobile mechanics make house calls in over 2,000 U.S. cities. Fast, free online quotes for your car repair.

GET A QUOTE

More related articles

Veteran and Military Driver Laws and Benefits in Idaho
The state of Idaho offers a number of benefits and perks for those Americans who have either served in an Armed Forces branch in the...
How to Avoid Back Pain in a Car
If you have back problems, sitting in a car for an extended period of time can be excruciating. Even without back problems, you could experience discomfort and soreness from...
Auto Safety Tips
Driving is more than a way to get from point A to point B. Owning and driving a car can also be a highly enjoyable experience. Whether a person is driving...


Related questions

Q: 1999 firebird every now and then dies while driving and low engine power light comes on

A bad mass airflow (MAF) sensor can cause loss of power, no starts, and lean or rich conditions. If cleaning the sensor did not get rid of the P0102 trouble code, then replace the MAF sensor and clear the...

Q: High speed bogging down

Engine misfires can be caused by a list of problems, but there are a few suspects that occur more than others. The primary culprits are simple – spark or fuel – usually manifesting in spark plugs, plug wires, the coil(s)...

Q: P1404 check engine code showing and EGR pintle is .5

Hello. Most of the time this is caused by a bad EGR valve. I usually remove the valve and inspect the ports for the EGR valve. If these ports are clogged then the problem will persist. It is possible that...