A4 P0171 Fuel Trim System Too Lean

"This Audi has the following error code stored in the diagnostic memory: P0171 00 [237] - Fuel trim system (Bank 1) - System too lean." It is typically set approximately every two weeks.

I couldn't detect any leaks, and the lambda value remained constant even when spraying with a leak detection spray.

However, the oil drain plug usually sucks in some oil, and it typically "splatters" out when you unscrew it. Are there any known issues with the crankcase ventilation valve in this engine?

Address 01: Engine Control Module (------CDHB)
Label file: DRV\06H-907-115-CAB.clb
Part number SW: 8K1 907 115 D, Part number HW: 8K1 907 115.
Part: 1.8l R4/4V TF H07 0002
Revision: A5H07---
Encoding: 010C000C02070058
Operating number: WSC 99999 1023 2097151
ASAM Dataset: EV_ECM18TFS8K1907115D A01003
ROD: EV_ECM18TFS8K1907115D.rod
VCID: AF2E5551F6812F39C0-80FA

2 error codes found:
4629 - Main relay.
P068A 00 [096] - Opens too early.
Sporadically - unconfirmed - checked since last deletion.
2811 - Fuel metering system (Bank 1)
P0171 00 [237] - System too lean.
Warning light ON - confirmed - checked since last reset.
Environmental conditions:
Error status: 00000001
Error priority: 2
Error frequency: 2
Mileage: 83,608 km
Date: 2017.06.22
Time: 09:01:42

Motor speed: 794.00 rpm.
Normalized load value: 22.4%
Vehicle speed: 0 km/h
Coolant temperature: 67 °C
Intake air temperature: 32 °C
Atmospheric pressure: 980 millibars.
Voltage at terminal 30: 13.970 V.
Lost count after OBD: 40

Readiness: 0000 0000

Hi,

What about the fuel pressure? Are the fuel filter and injectors verschandeln and free of obstructions?

Best regards, Rainer.

I didn't check the fuel pressure, but I could have also checked it using VCDS.
The engine is running smoothly, without any issues.
Okay, so we're taking out the fuel injectors to inspect them?

I would first like to examine the additive and multiplicative learning rates of the Lambda regulation method.
https://community.dieselschrauber.org/en/viewtopic.php?t=21836

Best regards, Rainer.

Evening.

The crankcase ventilation valves often fail in the A4 8K model. The error description fits perfectly: if you adjust something on the "cap" of the valve, you should hear a hissing sound with the engine running.

Best regards,

dieselschrauber wrote:

I would first like to examine the additive and multiplicative learning rates of the Lambda regulation. Okay, I'm ready. Please provide the German text you want me to translate. Best regards, Rainer

I already looked for it yesterday, but I couldn't find a corresponding MWB (Materialwirtschaftsbericht). Is this referred to by a different name in UDS ECUs?

The corresponding measurement value labels vary depending on the control unit. Simply type "lambda," "fuel," or "mixture" into the advanced measurement value blocks, and all entries containing that search string will be displayed.

Best regards, Rainer.

Yes, I tried, at least with Lambda. Also, Ada, Mul.

I will search for "gemisch" and "fuel" if I encounter him again.

"Mixture correction."

Best regards, Rainer.

It's normal for the oil filler cap to be slightly vacuum-sealed on the 1.8L and 2.0L TFSI engines. However, if the crankcase ventilation system (PCV) is defective, it will be very difficult to remove the cap.

Please provide support. DRV motor.

P087: Rail system pressure too low.
P0171: System too lean.
Speed: 1478 RPM.
Last 15.3%.
Speed: 54 km/h
Temp.: 96 degrees !!!!???
Temp.: 21 degrees (Normal??)
Pressure: 960 mbar.
Voltage: 14.224 V

[Translating...]

EOM

Again, what kind of engine?

Generally, a bit more text would be beneficial.

Benni wrote:

Again, what kind of engine? Generally, a bit more text would be beneficial.

PM for you.

Hi Sepp,

Please post a general overview ("Autoscan") instead of providing very limited information, as that just clutters the thread. Who wants to read that? "PM" (Private Message)? You, if you are looking for help?

Best regards, Rainer.

Okay, here's the protocol.