Lambda rule, additive and multiplicative adjustment factors

Hello Mr. XXX,

"Value range" is actually quite general and refers to a range of permissible or expected values.
For example, the coolant temperature of a warmed-up engine typically falls within the range of 85-100°C.

It has become quite clear, for example, regarding the lambda control and the engine speed range.
-25% to +25% / Setpoint: 800-6500, Actual Value: 640 (accepted) / 1000 RPM.
> It's clear that the catalytic converter temperature is controlled by the lambda sensor.
Range: -25% to +25%. Target: -10% to 0%.

This concerns the independent adaptation of the engine control unit to the measured air mass values and lambda values.

There is both an additive and a multiplicative factor here. Ideally, the adjustment values fluctuate around 0%. This fluctuation itself is due to the lambda control and catalyst monitoring systems.

> the lambda control system jumps between 23% and 26% when idling.

In other words, from the engine control unit's perspective, the engine is running too lean when idling.
So, either there's more air entering the engine than the mass airflow sensor (MAF) is measuring, or there's less fuel being injected than the engine control unit (ECU) intends.
Positive values indicate that more fuel is injected to reach the desired lambda value (the engine is running too lean). Negative values mean that the engine is running too rich, and less fuel is injected.

See Lambda regulation.

Best regards, Rainer.

XXX wrote:
...
Hello Mr. Kaufmann,
"The update worked perfectly. However, I have another question."
Please! Maybe you can help me.
"Specifically, this concerns a problem with an Audi 8E 2.0 (older model)."
Error code 16804 - Bank 1 Catalyst: Insufficient efficiency, P0420-001.
"Upper limit exceeded - warning light activated. This happens very often."
> A problem that is being discussed in all forums.
> First of all, I often checked the tire pressure for leaks.
> I was able to identify two damaged hoses and have repaired them.
"Then I let the car run for about an hour to properly warm it up."
> usually accustomed to short distances only.
After that, I started recording the measurements of all the relevant things that...
> Regarding the control of exhaust systems, unfortunately...
> Term "value range" not found.
It has become quite clear, for example, regarding the lambda control and the engine speed range.
-25% to +25% / 800-6500 (setpoint/actual) / 640 (accepted value) / 1000 rpm.
> It's clear that the catalytic converter temperature is being controlled by the lambda sensor.
Range: -25% to +25%. Target: -10% to 0%.
"So, what is the correct value when idling? Because in this case, it's like this..."
> the lambda control system jumps between 23% and 26% when idling.
"If I knew now whether the target value at idle falls within the range of -10% to 0%..."
"I might suspect that the lambda regulations aren't quite right somehow."
"is in good order." Please explain the term "value range" to me, because I don't understand it.
"However, it appears in many other measurement blocks. I can only imagine..."
> imagine that it is about...
> This refers to the range between idle and full load. So, in this case, it would be...
"resulting in a fuel consumption of approximately -25% at idle speed (640 RPM), with the lambda control system contributing roughly -10%."
> would have to. But she...
It fluctuates between 23% and 26%.
Here's the translation:

"However, what I also did was re-implement the readiness code."
> to create, which was also achieved on that day. All that was necessary for this test.
> Exams were passed.
Normally, the motor control will be working again within 2 days at the latest.
> It was illuminated, and now the problem no longer existed!
I promised myself to do it without incurring high costs (e.g., replacing lambda sensors or catalytic converters).
> It would be straightforward to create it, unfortunately not, and now after a good month.
Control is back!
And now I really need to understand this term correctly.
> Emission values. The car also passed the emissions test.
Unfortunately, I think the cat is gone because many people are only seeing...
Replacing the oxygen sensors didn't solve the problem; it was something else.
"Values can be caused by the defective catalytic converter. I will check it again."
> measure the exhaust emissions with an official testing device - who knows what the results will be?
> The regular scheduled maintenance has been completed. Maybe I can then do something very simple as well.
> To check if something is wrong with the cat.
...
Best regards,
XXX

Quote:

Some common values that we examine when diagnosing problems with gasoline engines that use a UDS control module: IDE00025-ENG167462, Coolant temperature. IDE00589, Fuel pressure. IDE00188, Fuel high pressure: current value. IDE00182, Camshaft adjustment, intake side bank 1: phase position. IDE00183, Camshaft adjustment, intake side, row 2: phase position. IDE00184, Camshaft adjustment, exhaust side, row 1: phase position. IDE00185, Camshaft adjustment, exhaust side 2: phase position. IDE00604, Short-term adjustment of fuel mixture for bank 1. IDE00597, Long-term adjustment of fuel mixture for bank 1. IDE00605, Short-term adjustment of fuel mixture for bank 2. IDE00598, Long-term adjustment of fuel mixture: B2. IDE01869, Long-term fuel trim for bank 1 at idle. IDE03794, Long-term fuel trim for bank 2 at idle.

In cases of unexplained performance issues, the variable valve timing system should be checked in particular.