digibum

Sorry, I mixed up N522 (Oil Pressure Control Valve) and N523 (Piston Cooling Oil Control Valve). N523 was replaced three times (because the error code directly indicated this valve), but the actual culprit was N522, which they hadn't touched until my last visit. It turns out I had the wrong valve in mind right from the start. I kept saying N522 was replaced, but it was actually N523.

I have great news! The issue was caused by a defective oil pressure control valve (N522) that measured an incorrect electrical resistance (0.8 Ohm). After replacing the valve, the fault code is completely gone and the car operates normally.

Honestly, I’m just completely baffled by this whole situation. How is it even possible that on a 2022 modern car, with all the advanced diagnostics, live parameters, detailed Freeze Frame data, and full ECU logs available, nobody—including the main dealer—can pinpoint the actual root cause of this error? We have clear, repeatable patterns (ignition ON, cold boot vs. warm engine, instant re-trigger with live Freeze Frames), yet the troubleshooting relies solely on throwing parts at the car and blindly waiting for factory support. It's frustrating to see that with all this technology and data at our fingertips, an electrical cold-start glitch can still completely stump the entire service network. ☠️

Thanks for the suggestion! However, it can't be related to the oil viscosity itself because the fault code P25AB00 triggers instantly on ignition ON alone (engine OFF) during a cold boot, before the engine even cranks or any oil pressure is built. Appreciate the idea, though!

The piston cooling oil control valve (N522) — replaced twice. The engine wiring harness. The main engine ECU. A brand-new Varta battery (installed by the dealership after they noticed a big voltage drop when starting cold). Checked all fuses and relays in the engine bay — everything looks completely clean with zero corrosion. The dealership has officially admitted that they have completely run out of ideas on what to check next. They have submitted additional inquiries to the technical support team, but the support process is painfully slow, highly unresponsive, or simply leaving questions completely unanswered. Current status: Despite replacing all these major parts and running all these tests, the issue is still not fixed.

Still waiting... The service center has been waiting for two weeks now for a reply from the importer (tech support) to finally figure out what the next step will be. Honestly, I'm at my wits' end with them and I'm this close to calling them up and giving them a piece of my mind about why everything moves at a snail's pace.

@Breezy_Pete thank you for your effort! This morning, I ran a scan on a cold engine and got the usual cold-start behavior, and refused to clear: Immediate rescan: I cleared the code (P25AB00) on cold ignition. OBDeleven automatically rescanned the ECU a second later and caught the code again immediately. Checking the Freeze Frame data, I noticed a new timestamp and slightly changed parameters. I retried clearing it twice, and after each clear, a new timestamp and slightly changed parameters appeared. The 60-second delay: After failing twice, I turned the ignition OFF, waited a full 60 seconds, and turned the ignition back ON. Upon scanning, the frequency counter had increased to 2. I cleared the code, and this time it stayed gone! I then drove to work with no faults at all, and the Start-Stop system worked perfectly the entire way. A fresh scan upon arrival at work showed zero faults. I also checked the fuse box in the engine bay — I pulled out and reseated all fuses and relays to ensure good contact. All pins and terminals look completely spotless with zero visible signs of corrosion or oxidation.

Tested the code after letting the car sit for 6 hours (cold engine): Cold Engine (Ignition ON, Engine OFF): The code was static and refused to clear. I tried clearing it 4 times in a row, but it reappeared instantly on every rescan without even starting the engine. Warm Engine: After driving to lunch and back, I cleared the code on ignition—it wiped cleanly and stayed gone. Will check the rest of the suggestions when I come home. And retray to clear fault when the engine is cold.

Could be corrosion or bad connector, where is this fuse box in the bottom of engine bay? I do have aditional fault's that are allways present and i never cleare those. Air Conditioning: Air quality sensor faulty (B10AF04 active). Dashboard: Function restriction due to communication interruption (U111000 static). Multifunction Module: Data bus error value recived (U112300 static). Multifunction Module: Fog mode active (C118E00 static)

DNFE / 2.0 TSI EA888 Gen 4 / 280 hp

I am attaching my full engine details from OBDeleven I'll check the voltages with OBDeleven. I can easily get the resting voltage (ignition ON) and running voltage after start. I probably won't catch the split-second dip during actual cranking due to the app's refresh rate, but I'll log what I can and post the numbers!

It was only a very short time — just a few seconds. Between step 2 and 3, I turned the ignition off, opened and closed the driver's door, and then immediately turned the ignition back on to run the scan. I will definitely try your suggestion of leaving a full 60 seconds (or more) with the ignition off before turning it back on... Yesterday, I replace the N522 valve once again, just to 100% rule out the possibility that the first new valve installed by the dealership was defective. When I replaced the valve, the engine was fully warm. After installing the new valve and clearing the code, I ran multiple tests and the fault code did not return. However, after letting the car sit for 3 hours to cool down, I turned the ignition back on and the P25AB00 code immediately returned. The issue seames to never occurs when the engine/oil is warm. It only triggers when the system undergoes a true "cold boot" with cold engine/oil parameters. During my lunch break, once the engine has completely cooled down again, I will repeat the full test sequence on a cold engine, including leaving 60+ second gaps between ignition cycles as suggested earlier. I will post the cold-start results as soon as I complete the tests!

I just upgraded to the OBDeleven PRO subscription to get full access to Freeze Frame data, and I stumbled upon a very interesting discovery regarding the fault's behavior: The code returns instantly on ignition alone (before even cranking the engine)! Here is exact sequence I tested: Cleared the fault code (P25AB00). Turned the ignition off. Turned the ignition back ON (engine OFF / no cranking). Ran a full diagnostic scan. The fault immediately reappears as soon as the ECU powers up, even without the starter motor engaged or the engine running. The PRO version extracted the raw Freeze Frame values. While I can't interpret these raw numbers (HEX) myself, I have forwarded the PrtSc directly to the dealership service team so their technicians can analyze the exact ECU parameters at the moment of failure. Will keep you updated once I hear back from them!

Hi Alasdair, Honestly, I am not sure whether they cloned the old ECU or flashed it from scratch with default factory software. What I do know is that they performed programing. Regarding the code: since picking up the car from the dealership, I have cleared the fault code twice using OBDeleven. Both times it cleared fine, but as soon as the engine cools down and sits for a while, the exact same static code (P25AB00) persistently comes right back on the next cold start. So whatever data or software condition is causing this, it keeps triggering the fault continuously.

Hi everyone, Can anyone point me to the exact physical location of the Piston Cooling Oil Control Valve (N522) on the 2.0 TSI engine (280 hp)? The VAG part number for the valve is 06K115243L. I know it's located somewhere on the engine block near the oil pump module, but is it accessible from the top, or do I need to drop the undertray and get to it from underneath (front side of the block facing the radiator)? A photo/description of where to look would be hugely appreciated!