Codes P0520 and P0406

I attached the tests for these codes. Unfortunately the only way to find out is to run through the tests. However, I suspect that the issue is causing both of them. So pick one and run though it and when you make that repair, I suspect you will fix the other.

Let me know if you have questions but these tests are a little heavy in electrical testing so I can help answer whatever you are not sure about. Thanks

The P0520 is almost guaranteed to be the oil pressure sensor itself, at the rate they fail the dealers have a hard time keeping them in stock. I've replaced so many of them I can do it without even looking. On that engine it's hiding behind the alternator, you remove the serpentine belt, then the three bolts that hold the alternator on, just move it aside, remove the wiring connector and replace the sensor. You usually will see nothing outside that shows it failed but the common thing is the inner diaphragm between the oil and the sensor fails and they start to "stick" at a pressure other than zero at initial start. That trips the code even if the oil pressure gauge or information shows it's working. To remove it you need an oil pressure sender socket like a Lisle 13200

That means that not only did the internal diaphragm fail but the pins were not sealed as well. Clean out the oil and replace the sensor. I have yet to see where the sensor wasn't the problem for that code as long as the engine runs. There is a TSB on it and in all cases the first step is, replace the sensor. The EGR high may be a wiring issue so test as above to determine if that is the case.

Okay. So just to clarify, did that correct the issue or do you still have the EGR code? If you do, to Steve's point, we will need to run through that EGR testing to determine what it is if the valve is not the issue.

That is great news. Thanks for the update. Talk to you next time.