Overload A6 2.7 BPP P242F - Max Load Exceeded

On June 27th, I had the service lights reset on this car because all three warning lights were on. I didn't think much of it at the time, as it's primarily used for short trips.
I only had the P242F error code in the diagnostic memory at that time.

Three weeks later, the same problem has reappeared, but now with an additional lambda error code P2196 - 002 - indicating a rich fuel mixture.

I just pressure-tested the intercooler system and I heard a hissing sound at the front, where the two intercoolers are connected. I removed the pipe, and it seems like there was some damage that wasn't properly repaired after an accident. The connection of the aluminum pipe was crushed. I straightened it out and pressure-tested it at 0.5 bar, and now it's sealed.
It was only slightly oily all around, just like the smaller engines with the quick-release fasteners.

The temperature sensors in the DPF (Diesel Particulate Filter) have ambient temperature when they are cold.
The differential pressure sensor in the LL (likely referring to a ventilation system) is reading slightly high, probably due to the increased load. However, the rear connection is not quite tight and cannot be tightened.

I then did some logging runs, and I noticed something strange about the AGR (selective catalytic reduction) system.
Sometimes, at idle, the EGR valve is being controlled at 95% (which it should be closed), and the MAF sensor value is too low or the same. I've highlighted this in the log.
In this log, I don't think the lambda value is too low; when accelerating at full throttle, it goes down to a minimum of 1.1.

It's possible that if the AGR valve is stuck, it could be adding more exhaust gases, which would cause the particulate filter to become clogged more quickly.
The ash volume is 0.39L.

Okay, now I'm not sure whether I should deactivate or replace the AGR valve, or if the DPF is simply full due to mileage.

Hello,

Your mass airflow sensor readings are strangely low. Either the mass airflow sensor is faulty, and you have another issue preventing DPF regeneration, or your EGR valve is sticking or defective. I would remove and inspect it, especially considering the mileage. If it's mechanically okay, I would then look into the mass airflow sensor. Is the engine control unit software original?

Best regards, Rainer.

I'm also fluctuating between a possible LMM and AGR leak, even though the second log showed it was okay again.
The software is mostly original, but the intake manifold flap function has been disabled. The intake manifold flaps are now always open, which results in slightly reduced cylinder filling at partial load. However, this has not caused any problems so far (for 3 years) and has not been an issue with other vehicles.
I will try to replace the locking nuts on the lines connected to the differential pressure sensor tomorrow, and possibly disable the EGR valve. Unfortunately, the login function for the 4-cylinder engine to disable it is not working here.

What I don't quite understand is that the calculated Russian mass is 17g, while the measured value is 10g, and yet he's writing "overload."

If it offers any reassurance: Even with my vehicles, the measured and calculated values were never identical.

Today, I replaced the over-molded boots on the differential pressure lines and they were faded. Now they are securely attached and leak-proof again.
Then I tried to calibrate the differential pressure sensor, but it's not possible with software version 0030; the value "1" is not accepted in the adjustment channel.
Get the software updated to version 0060, and now the customization is working.

Immediately after starting and for the first few minutes, the lambda value in the log is always 1, and the lambda sensor electronics display 11001001. After a few minutes of driving, the lambda value is then displayed, and the bit pattern changes to 10001001.

Let's assume the oxygen sensor doesn't start working until a certain time (temperature). However, it still happens even when you turn off a warm engine and then restart it. Then, it starts again with the error code "Lambda 1" and "11001001".

Here's an explanation of the bit pattern.

X X X X X X X 1 Full load regulator on/off.
X X X X X X 1 X Full load.
X X X X X 1 X X Regelabweichung negativ, d.h. Mixture is too fatty.
X X X X 1 X X X System error.
X X X 1 X X X X Oxygen signal invalid or no correction via lambda sensor adaptation.
X X 1 X X X X X Motor in starting position.
X 1 X X X X X X Time limit or quantity limit active.
1 X X X X X X X Regeneration, Exhaust Gas Aftertreatment.

Sure, here's the translation:

"What is a full-fledged [something]?"
I have a system error related to the engine mount valve.
Time limit or quantity limit active?
Regeneration of exhaust aftertreatment system? I couldn't find any indication that it's regenerating. Post-injection is disabled, and the regeneration request is 0.

What's also suspicious is that the throttle valve is always being controlled, except when at full load and thrust. Normally, it should always be open and only close when the engine is being turned off, and it should close during regeneration according to the characteristic curve.

I also drove with the AGR vacuum hose disconnected, and in that case, the target and actual mass airflow values were almost identical.
The error code was stored in the system's memory, but surprisingly, the warning light wasn't illuminated.

chli1976 wrote:

What also makes me suspicious is that the throttle valve is always being controlled, except at full load and thrust. Normally, it should always be open and only close when the engine is turned off, and according to the characteristic curve, it should close during regeneration.

Normal.

As you might expect, a long time ago this valve was simply a shut-off valve.

Best regards, Rainer.

Quote:

X X X X 1 X X X System error

This likely refers to the exhaust cleaning system, not the engine mount.
hg
Herbert.

Even if there is currently no error related to the exhaust gas treatment system?

Maybe it's the spark plugs?
Where did you get the layout for the bit pattern?
hg
Herbert.

It might be possible.

I sent you a private message.

Initially, it was translated without any guarantee of being free from errors.
If the oxygen sensor occasionally indicates a "rich" mixture, it may be damaged itself (which wouldn't be surprising given the mileage), or there may actually be too little residual oxygen in the exhaust.
The actual air-fuel mixture, which is sometimes lower than the target value, would be consistent with this, and the engine would also need to be operating within the soot reduction range.
The air/exhaust mixture should ideally be fine-tuned based on the lambda value, and roughly adjusted using the engine map.
Perhaps it would be helpful to examine the LM values, lambda values, and electromagnetic compatibility (EMC) limits together.
Shouldn't the actual value of the lambda sensor be higher than the target value without an EGR system?
The 0.39l ash volume should still be acceptable, if you believe the reported limit of 0.46l for the engine found online. However, this value is calculated from data from all previous regeneration cycles and may actually be different. An excessively high differential pressure could then lead to the sporadic error message "Load exceeded."
In my case (CR), the field regeneration is always based on the calculated soot mass, which is usually significantly higher than the measured value.
hg
Herbert.

Yes, the LMM (likely referring to a lambda measurement or similar) should be above the target value without exhaust gas recirculation. I mentioned in the previous post that at full load, the target and actual values should be the same. In low load (LL), the target is 280 mg/H, but the actual value is 450 mg/H.
Normally, CR engines with DPFs achieve smoke emission limits through the LD (Load Dependent) system, so I didn't log those limits. However, I believe that with the V6 engine, it's controlled via the lambda sensor, but I didn't think of that until later.

"@Rainer, is he absolutely sure whether the oxygen sensor is used for the V6 engine?"

Regarding the differential pressure:
After securing the rear lines, I have a maximum differential pressure of 250 mbar at full load. In the low-load range, it went from 7 mbar to 21 mbar. If I compare these values to the standard values in the thread, I'm in a very good range, assuming the differential pressure sensor is working correctly.

Quote:

Normally, CR engines with DPFs achieve smoke limits through the LD (Load Dependent) system, so I didn't log those limits. However, I believe that with the V6 engine, it's controlled via the lambda sensor, but I didn't think about that until too late.

Okay, that's something that needs to be checked!

Quote:

@Rainer knows for sure whether the oxygen sensor is used for the V6

.
But not by memorizing, like knowing exactly how the motor works.

Logging torque limits and checking air mass/lambda makes sense in this context. Since the amount of fuel injected is never greater than what is determined by the torque limit set via the transmission, excessive soot can realistically only be caused by a lack of air.

Please also check the oil level (is it too high?) and consider excessive oil consumption as a potential source of smoke or soot.

Best regards, Rainer.

Thank you, Rainer.
Indeed, it has a little too much oil in it.