What Is the P0418 Code?
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The P0418 code indicates a problem with the circuit that gives feedback on your secondary air injection (SAI) system. If the Powertrain Control Module (PCM) or Engine Control Module (ECM) indicates that the SAI system circuit isn’t responding appropriately, it will trigger this code. Note that the code doesn’t necessarily mean that the SAI system has an actual fault within it. It just means that the control circuit isn’t responding appropriately.
More About Error Code P0418
The SAI system supplies fresh air to the exhaust stream, which is part of reducing emissions from your vehicle. In some vehicles, the system does double duty, helping your catalytic converter rise to its operating temperature when you start the engine. It needs to monitor fluctuations in air pressure to regulate and distribute the air correctly, and when the PCM is unable to do that due to an issue with the voltage signal, it will set code P0418.
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What Are the Symptoms of a P0418 Code?
Usually, there are no severe drivability symptoms of code P0418. The most common symptom is to see the check engine light or malfunction indicator lamp turn on and nothing else. In certain cases, however, your PCM may trigger “limp mode,” also called “limp home mode,” which can cap your vehicle’s maximum engine speed and shut off non-critical systems like your air conditioning system to improve engine performance. It depends on the underlying cause, what your specific vehicle uses the SAI system for, and how your vehicle’s manufacturer has decided to handle the P0418 trouble code.
What Are Some Causes of a P0418 Code?
There are many possible causes of the P0418 code. A bad SAI pump relay or faulty SAI pump are some of the more common causes, with faulty wiring and connector issues frequently causing these concerns. Most secondary air injector systems will also have valves to prevent the backflow of exhaust gases to the SAI pump. If the valves fail, hot exhaust gases can damage the air injection pump, leading to this code. The SAI system fuses may also be blown. In some very rare cases, it may be an issue with the PCM, although the most common PCM issue is just an issue with software that needs an update.
How Serious Is the P0418 Code?
If the P0418 error code has not resulted in severe drivability issues, it may not be extremely severe. In most vehicles, the emissions system isn’t a critical part of the functionality. However, if the P0418 code is active, your vehicle likely won’t be able to pass an emissions test, and the longer you leave it, the more likely it is that you might eventually see an actual impact on your engine condition. While code severity might not be very high, getting help with it as soon as possible is important to protect the engine from damage.
Can I Still Drive with a P0418 Code?
Most of the time, you will physically be able to drive with DTC P0418 active. Although technically possible, it is highly uncommon for the P0418 code to cause your vehicle to enter limp mode. That means most people can drive with this code active, but you still shouldn’t drive it consistently. Getting a certified mechanic to help you fix the code if it’s active is best.
How Easy Is It to Diagnose a P0418 Code?
Because there are so many possible causes of the P0418 code and the SAI system is often difficult to understand, the diagnostic process for code P0418 can be difficult. It’s a generic powertrain code, meaning you need knowledge of the repair steps for your vehicle’s individual make and model. You must also inspect system wiring and electrical connections for damage, the SAI system fittings and hoses, general system fuses, one-way check valves, and more. If you’re unsure how to do this, you should talk to an expert about a solution.
How Difficult Is It to Inspect a P0418 Code?
There are lots of components of the P0418 diagnostic trouble code that require inspection. However, if you’re not especially knowledgeable about how the SAI system is supposed to look, inspecting all the necessary components can be very difficult. The required technical skill, knowledge, and specialty tools can be much too difficult for many beginner DIYers. This is a code that you may need to request help from an expert on.
Need Additional Help with Your P0418 Code?
Many people need additional assistance with the P0418 code. And if you’re one of them, you’re in luck. There are plenty of ways to get help with this code. An expert will have done thousands of repairs just like this, so they’ll know the repair procedures required, the vehicle information source they need to consult, and what tools they’ll need to use.
First, find an auto repair shop in your area. A local automobile repair shop will help you get in and out as soon as possible.
Second, you’ll want to check out the OBD-II database at KBB.com. If you’re experiencing other fault codes on top of code P0418, this database will help you see what those codes mean in OBD-II-equipped vehicles and how to tackle them.
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