Can a bad IAC cause a misfire?
Secondly, can a bad idle air control valve cause misfire? The cause is often a problem in the idle air control system. The first thing to check is the intake vacuum with a vacuum gauge. An EGR valve that is leaking can also act like a vacuum leak and cause a random misfire.
What are the symptoms of an idle air control valve ( IAC )?
Another symptom of a potential issue with the idle air control valve (IAC) is; an illuminated Check Engine Light. If the engine control module detects an issue with the idle air control valve circuit or signal; it will set off the Check Engine Light to notify the driver that there’s an issue.
Why does the Check Engine light come on when the engine is idle?
The check engine light in your vehicle is designed to turn on if the Engine Control Unit (ECU) identifies an issues with how the engine is running. Look at your dashboard; if the check engine light is on in conjunction with idle issues, it may be because the idle control valve is malfunctioning.
How can I tell if my idle control motor is working?
Look for a difference in idle speed. Allow the engine to run for a minute so it settles to a consistent idle, then take note of any difference in the idle RPMs versus the idle you observed earlier. If the idle has not changed at all, it’s likely because your idle control motor has not been functioning.
Can a code reader be used to test an IAC?
Code readers and OBD-II scan tools don’t have the necessary bi-directional controls to test an IAC. OEM-level scan tools are awesome because, on many vehicles, you can directly control the IAC, taking the PCM completely out of the loop.
Another symptom of a potential issue with the idle air control valve (IAC) is; an illuminated Check Engine Light. If the engine control module detects an issue with the idle air control valve circuit or signal; it will set off the Check Engine Light to notify the driver that there’s an issue.
The check engine light in your vehicle is designed to turn on if the Engine Control Unit (ECU) identifies an issues with how the engine is running. Look at your dashboard; if the check engine light is on in conjunction with idle issues, it may be because the idle control valve is malfunctioning.
Look for a difference in idle speed. Allow the engine to run for a minute so it settles to a consistent idle, then take note of any difference in the idle RPMs versus the idle you observed earlier. If the idle has not changed at all, it’s likely because your idle control motor has not been functioning.
Code readers and OBD-II scan tools don’t have the necessary bi-directional controls to test an IAC. OEM-level scan tools are awesome because, on many vehicles, you can directly control the IAC, taking the PCM completely out of the loop.