AGR at 100% - Performance and Optimization

Hello, my VW T5 2.5 TDi with electronically controlled AGR (Exhaust Gas Recirculation) has an intermittent issue with the "0665 LD regulation limit exceeded" error code at 129,000 km. After a test drive focusing on the LD (Load Demand) and LM (Mass Flow), everything seems to be within the normal range or even slightly above. However, I noticed that the AGR control value is always stuck at 100% and doesn't change at all.
Okay, the question is whether the AGR (Abgasrückführung - Exhaust Gas Recirculation) is sending a value to the ECU (Engine Control Unit) that is constantly displaying 100% duty cycle. Could it be that the mechanical valve position (which might be stuck) is sending a value to the ECU? Or why is it always showing 100%?

Hello Klaus,

"In my opinion, a control value of 100% is only displayed by the control unit if the EGR valve is defective."
Why don't you perform an actuator test?

Best regards, Rainer.

Sure, thanks Rainer.

Okay, so it's still the same, 100%, no matter how much I accelerate.
The actuator diagnostic is performed as follows: at 0%, the reading is 480 mg/H, and at 10% (it doesn't go higher), the reading is 250 mg/H, alternating between the two values.
At idle speed, the target value in the engine control module (ECM) is 280 mg/h for cylinder 3 and 480 mg/h for cylinder 1, but the actual value is different.
Therefore, that would be incorrect. However, if all the air is passing through the mass airflow sensor (MAF), then the EGR valve should be closed.
So, is it broken?

Quote:

The actuator diagnostic is performed as follows: at 0%, the value is 480 mg/H, and at 10%

.
Did you perhaps make a typo with the 10% and mean 100%?

With which tool did you determine these values, and is the dataset original?

Best regards, Rainer.

No, nothing is mistyped, it's not going up more than 10-12%! The TV won't go any higher!
Version RKS908.2 is installed. The dataset is present on both original devices, and there are no performance changes.
I'm now going to check a different, undamaged 2.5-liter engine. It's a bit newer and also has the EL AGR version, with approximately 60,000 km on it.
The setpoint was 350mg/H cold, but the actual value was lower, and the other one was warm, which likely indicates less lubricant.
I'll go ahead and do the actuator test there.

edit:
There, the actuator test only applies up to that point.
13.9% increase = 290 mg/H and at...
It's back to 490 mg/H.

For LL, with the same setpoint of 330 mg/H and 80% TV, the values are considered normal.

Okay, good news: I just got the car back here.
AGR valve (approx. 200.-) installed and everything is working properly again.
Actuator diagnostics are working correctly, and in the basic settings mode, the 19% value matches the desired 19% setpoint. I haven't made any changes there.
In the LL (likely referring to a specific system or process), approximately 80% of the actual AGR (Air-to-Gas Ratio) matches the target AGR.

"Thank you" to everyone for the quick help; it was actually a simple mistake, but often people are too hesitant to simply order the part and install it themselves. It's easier to go with a friendly service provider.

Okay, here's the translation:

"100% TV is disabled on the T5, so no changes should have been made to its performance."

Thank you for the feedback .

Hello, here they are again, my 100% TV..
So, after encountering the "boost pressure below regulation" error, I searched for leaks in the air intake system and found a black, greasy spot on the intercooler, which also had a sooty residue.
Okay, so I installed a new oxygen sensor and new green seals, along with a front bumper, wheel arch liners, etc. It took 3.5 hours to remove everything. Now, during the short test drive, it didn't go into limp mode, but the air mass was 550 mg/H from the start, and it should only be 350, at 100% throttle.
Warum denn, wo doch das el. Is AGR new?
During the journey, the LMasse value, as far as I could see, remained consistently at 100% TV.
However, upon restarting, the difference in air mass returns to 100%.
The boost pressure was always within an acceptable range and closely followed the target value.
During the EGR actuator test, I assessed the air mass control as being OK.
Why is a 100% duty cycle making a comeback?
Can I reset or recalibrate anything that was learned due to the missing intercooler?

Hello,

You can try resetting adaptation channel 0 using VCDS (clearing the learned values); it's at least worth a try.
I'm not sure why the control system is behaving so strangely. Is there a software update available for your engine control unit?

Best regards, Rainer.

Thanks, Rainer, I'll do it tomorrow.
Given the questionable and potentially recurring emergency mode, I don't want to send the N on the trip, so I'll try it out myself tomorrow.

Hello Rainer,
"Adaptation" is only possible for the Aschelern value and WFS, etc., but not for AGR.
"However, in the default settings mode, I have the 'Block 003' button, which has options for 'On', 'Off', and 'Next', and it is currently set to 'On'."
Allow it to run, as the setpoint and actual value will adjust together smoothly with the control system.
I did the same thing with the 011 block's boost pressure regulation.
Now the AGR (Automatic Gain Control) is set back to 82.1-82.9 TV in the LL (Low Latency) mode, but it was the same situation last time. Then it went back up to 100.
The first operational run was fine - no emergency mode and good performance.
I'll keep an eye on the AGR control.

The STG 070 997 016 K.
Version: R5 2.5L EDC 000SG 2604
Encoding: 0001172
I would need to check with VAG or Rosstech to see if there is a newer version available.