Verification of EGR cleaning

Clean it all, at least every 50k miles.

Concur.

 

No, I was talking about the routine self-test done by the car, whose result you can look at by retrieving the mode-6 monitor result.

 

That’s a non-continuous monitor and not an active test. Those are different. Both have a value for EGR verification.

The test result is a pressure delta between when the EGR valve isn't open and when it is.

That is not my interpretation of this monitor value. It does not include/know the position of the valve, it’s just a straight up monitor average of MAP flow compensated for potential open/close abnormalities. As you will likely disagree, please supply information how this event is included.

I would recommend to test/use the active test if they have TS - and want to test the valve open/close effects on flow kPa prior to pipe and manifold.

This data can indicate issues with the valve being clogged/obstructed.

 

Sure, but that’s not preventive in my book, it’s active remediation.

It’s indeed a DIY and should be done, but it seems impossible to prevent due to the engineering design flaws,

 

Semantics?

 

Not really. But; Let’s leave that focus alone (I could go on and on..).

It’s very relevant to clean the EGR.

There is no way to prevent it. There are some ways to verify it.

Merry Christmas to y’all.

 

Post #15 upthread explained how and when the ECM's self-test is performed.

If enough time has elapsed to repeat the test, or if a code clear has been done and the monitor status is incomplete, the ECM will wait for the next opportunity when:

• the engine is warm (70 ℃ or more)
• RPM is 950 to 1600
• operation is fuel-cut coast or decel (fuel has been cut for at least 2 seconds)
• the engine load has been stable for more than 1.2 seconds
• RPM is holding constant within ±20 RPM

Under those conditions, the fuel-cut, spinning engine is pumping a stable vacuum (down around single-digits kPa absolute pressure) against the closed throttle plate. The ECM recognizes that opportunity and conducts a three-second test in which it notes the MAP reading with the EGR valve closed, notes the new reading with the valve opened a certain amount, and subtracts the first from the second. The result is recorded as the monitor value.

If the stable test conditions don't continue long enough to complete the test, the result is discarded and the ECM continues to wait for the next suitable opportunity.

If you live in a jurisdiction with inspections, and an inspection is coming up and the status of this monitor is incomplete, you can hurry completion along by following the "confirmation driving pattern" given for P0401 in the repair manual, which is nothing more than driving so as to create a suitable opportunity for the test on purpose. Or, if there is no hurry, you can just keep driving the car normally and the test will be conducted as soon as the right conditions arise in your normal driving.

 

@ChapmanF I know how monitors work. It’s not the same as the active test - that is only available with TS as I understand it.

Can you please, with so much knowledge, ever mention some other knowledge or input as also relevant or ballpark correct?

As many likes as you have received, you could also deliver some, at least for that holiday spirit. Not to me, but anyone. It would be refreshing.

Merry Holidays!