Check engine light turned on and code P1491

P1491 - Malfunction In EGR System

You're in the wrong system. The biggest mistake most competent do-it-yourselfers make is diagnostic fault codes never ever say to replace a part or that one is bad. Fault codes only indicate the circuit or system that needs further diagnosis, or the unacceptable operating condition. When a sensor or other part is referenced in a fault code, that part is the cause of that code only about half of the time. First we have to rule out wiring and connector terminal problems or mechanical problems associated with that part before we waste our customer's money on an unneeded part.

As you can see in this definition, it only says there's a problem with the EGR system. It doesn't say to replace a part. The first step would be to use a scanner to command the EGR valve to run through its operation to see if it is working, then to watch what happens to the exhaust gas, (oxygen sensor readings), to see if the system is working. We have to know what is not working properly to know where to start.

Please keep us updated with what you find.

If this is on a new topic, you should start a new question for two reasons. First, each one gets categorized in such a way as to make them searchable for others researching the same problem. When a post covers multiple issues, others may never find what was added later.

The other issue is, unlike other forums where anyone can chime in and confuse the issue, this has become a private conversation between just the two of us, although some other experts might add some comments. As such we are the only people who get notified automatically when the other adds a reply. None of the other experts will see your new question or have a chance to reply. That may not get you the help you need. You are welcome to think I'm a genius, but there are some topics I leave to other experts who can do a better job for you. When you start a new question, they will all get to see it, then one of them who feels competent in that area will reply.

You can reply back here with your new question, but if it's not related to this one, also go here:

https://www.2carpros.com/questions/new

and copy and paste it in the new question for everyone to see.