Codes/brands This Page Will Cover
- P1516 IMRC Input Error (Bank 1)
- P1517 IMRC Input Error (Bank 2)
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What Is the P1516 Code?
Symptoms
Causes
Seriousness
Can I Still Drive?
Diagnose
Difficulty of Inspecting
Get Additional Help
The P1516 relates to the Intake Manifold Runner Control (IMRC), which is a system housed within the engine of the car that is electronically controlled and has a motorized actuator and corresponding linkage that rests on each bank of the engine. This code relates to bank one, which is the side of the engine that contains the number one cylinder and shows up often in Ford vehicles. Each IMRC housing consists of an aluminum casting with two intake air passages for each cylinder. One passage remains open, while the other opens and closes through a valve plate designed in a butterfly fashion. The system housing also makes use of a return spring within that ensures the plates close when they need to be. At the same time, the motorized actuator houses internal switches that provide feedback to the Powertrain Control Module (PCM) to indicate linkage and plate position.
At RPMs under 3000, the vacuum solenoid is energized, which kicks on the manifold vacuum. Once this happens, the butterfly valve plates close up. Then, when RPMs reach levels above 3000, the vacuum solenoid gains power, which empowers the vacuum solenoid and allows the vacuum to make its way from the actuator. Once this process is complete, the butterfly valve plates open back up. The P1516 code sets when the signal detected during this process is outside of an expected calibrated range, usually set by the manufacturer.
What Are the Symptoms of a P1516 Code?
The P1516 code is usually not met with symptoms other than the Check Engine Light illuminating on your vehicle’s dashboard. This is because most of the happenings with this process occur in and around the intake manifold and are not immediately noticeable to the driver. However, there are situations where the P1516 code can lead to damaged vacuum lines, and this can cause issues with how your vehicle idles or accelerates. This is because the air and fuel mixture has been affected, and your engine may now start idling rough or even stall out at stoplights. You may also notice a decrease in the fuel mileage your car gets if these issues persist.
What Are Some Causes of a P1516 Code?
One of the most common causes of the P1516 code issue is a leaky vacuum reservoir or damaged vacuum lines that could be causing poor vacuum levels to be present. You may also find that damaged vacuum lines can cause the issue to appear, as well as a defective vacuum actuator. The IMRC actuator cables or gears seizing and the IMRC housing return springs getting damaged or disconnected can also lead to the P1516 issue. In addition, the IMRC lever shaft can often be stuck or disconnected, or you may find that the control circuit leading to the IMRC is open or shorted, causing this issue to arise. Finally, a damaged or defective PCM can cause the code to set, although this is the rarest of the causes.
How Serious Is the P1516 Code?
A P1516 code can become a severe issue if ignored. This is because any problems dealing with the air and fuel mixture process of your car can seriously affect how your engine operates going further. This is why you should have this issue addressed by qualified technicians at a certified service center as soon as you are aware of the problem. That way, you can prevent further strains on your engine’s internal components and contain this issue before it causes costly damage.
Can I Still Drive with a P1516 Code?
As mentioned, the P1516 issue can lead to further damage to your engine’s internal components if left ignored and should be inspected immediately. Because of this, qualified technicians do not recommend driving your car because you’re continuing to force your vehicle to run on a bad air and fuel mixture. Also, any vacuum leaks present could grow in severity from continued driving and lead to more costly damages to your engine. Instead, take proactive steps to get your vehicle to a technician so that you avoid costly repairs.
How Easy Is It to Diagnose a P1516 Code?
Diagnosing a P1516 issue isn’t easy and involves several steps to get to the bottom of the issue. This is why certified technicians can best handle this process as they will have worked with IMRC systems and know what to expect. With that said, the technician will first inspect the IMRC cable routing to make sure cables are not binding or improperly routed. They’ll also assess the cable core wire at the IMRC housing attachment and ensure that it has enough slack while ensuring that the lever has contact with the closed plate stop screw. Next, for vacuum-operated IMRC systems, the technician will ensure that the sensor linkage is attached and secure. Finally, they will make sure that the IMRC return spring is strong, operating correctly, and that the plates can open and close fully.
How Difficult Is It to Inspect a P1516 Code?
The inspection process for the P1516 is complex and should not be attempted at home as a DIY project because a poor diagnosis can lead to much more severe issues. Technicians with prior experience repairing these issues should handle the inspection. The technicians will look to repair or replace any cable routing or cable core wires located at the IMRC housing attachment if they are damaged or not working correctly. They will then repair the IMRC actuator lever and replace the vacuum actuator itself if needed. If the IMRC return springs aren’t operating as they should be, then the technician will look to replace those as well so that the IMRC system can work as intended. Finally, they will replace the PCM if needed, although this rarely is the case.
Need Additional Help with Your P1516 Code?
By following our guidelines here, you’ll be able to spot the first signs of the P1516 issue and will be able to take the steps needed to inspect and repair the problem to keep your vehicle running longer. For more information on these and other issues, visit our auto repair guide.
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