The issues that trigger a P0507 code are usually not severe enough to prevent you from driving your car, but it can cause some difficulties. Arm yourself with the necessary information to address this trouble code with the guide below.
What Does the P0507 Code Mean?
A P0507 code is a generic powertrain code that stands for “‘Idle Control System RPM Higher than Expected.” This OBD-II code belongs to a series of fault codes (P0505 to P0509) that pertain to a fault in the idle control system, and it means that the engine computer has detected that the engine idle speed has exceeded the manufacturer’s pre-programmed specifications for a certain amount of time.
Maintaining a proper idle speed plays an important role in reducing tailpipe emissions and preventing the engine from stalling.
On many older vehicles, the car’s primary computer, which is often referred to as the powertrain control module (PCM), regulates the idle speed by controlling the movement of the Idle Speed Control (ISC) valve. When open, the ISC valve—also known as an Idle Air Control (IAC) valve—allows air to bypass the throttle, increasing idle speed.
Closing the valve decreases bypass airflow, resulting in lower RPM.
Typically, when the throttle is closed, the PCM determines idle speed by measuring engine RPM via the crankshaft position sensor. The PCM also uses data from additional sensors, such as the AC pressure switch, coolant sensor, and speed sensor, to regulate idle speed.
It’s important to note that most newer vehicles use an electronic throttle actuator system (ETC) rather than an ISC or IAC valve. In an ETC system, the mechanical throttle linkage is eliminated. In its place, the control module (usually the PCM) uses an electric motor to operate the throttle body. The PCM primarily looks at the accelerator pedal position sensor (APP) and throttle position sensor (TP) to determine throttle operation.
As was mentioned, code P0507 will set when the PCM determines that idle speed exceeds a predetermined specification for a certain amount of time. The standard RPM per vehicle varies depending on make and model, but most engines should ideally run between 600 and 800 RPM while idling.
For example, some GM vehicles will trigger code P0507 if the engine computer clocks an idle speed that is 200 RPM above the recommended range.
What are the Possible Causes of the P0507 Code?
The most common reason that sets off a P0507 code is not actually a problem with the idle speed control system, but rather an engine vacuum leak. In most cases, the code gets triggered even if the Idle Air Control (IAC) valve is closed, which only means that there is a vacuum leak and the system is trying to decrease idle speed by closing the idle air bypass circuit.
It’s a good idea to start by ruling out this problem before checking for other possible causes:
- Engine vacuum leaks
- Faulty or clogged Idle Speed Control (ISC)/ Idle Air Control (IAC) valve
- Problems with the throttle body and/or electronic throttle actuator (ETC) motor
- Engine mechanical problems
- Restricted exhaust
- Circuit issues, such as damaged wiring and loose connections
- Issues with the air intake system
- Sensor problems
- Issues with the positive crankcase ventilation (PCV) system
- Control module or data network problems (rare)
What are the Common Symptoms of the P0507 Code?
It’s best to address a P0507 code as soon as you can to prevent possible engine damage, which will be more costly to repair.
Here are some of the symptoms you might observe when the code is set:
- Check engine light turned on
- Difficulty starting the engine
- Engine stalling
- Rough, fluctuating, or high idle
How to Diagnose the P0507 Code
As you can tell, there are quite a few issues that can trigger code P0507. As such, diagnosis can be difficult. However, there are a lot of online resources you can use to help you in diagnosing the root cause of this error code.
Listed below are a couple of videos that can give you an idea of the troubleshooting process:
How to Fix the P0507 Code
With several possible root causes, OBD-II codes typically aren’t easy to diagnose and fix. You’ll have to pinpoint the root cause of the trouble code first before you can proceed with the repair.
Even then, you’ll have to check if there are vehicle-specific instructions on how to address the problem. Therefore, make sure to check your owner’s manual before doing any repairs. You may also want to consider getting a repair manual, such as those from Chilton.
Or get yourself an ALLDATA single-vehicle subscription for detailed repair information that you can use for DIY projects.