Hey everyone,

I’m looking for some insight regarding an issue with a 2022 Skoda Superb Combi 2.0 TSI 4x4 (280hp). The car has 130,000 km on the clock and was imported from Germany.

The Issue: The Check Engine Light (CEL) is on. Upon startup, the dashboard also displays a "Start-Stop System Error."

Diagnostics: Using OBDeleven, I pulled the following fault code:

• P25AB00: Piston Cooling Oil Control Circuit High

What has been done so far:

1. Solenoid Replacement: The dealership technicians first replaced the valve associated with this code—if I’m not mistaken, this is the N522 valve, which regulates the oil flow for piston cooling jets. This did not fix the problem.

2. Wiring Inspection: They spent about two weeks troubleshooting the wiring harness between the N522 valve and the ECU. They eventually found a potential fault and performed a wiring bypass for a specific cable. After this, the error disappeared.

Current Status: Two days later, the error returned. The symptoms and the fault code are exactly the same. It triggered in the morning immediately after a cold start.

I cleared the code, but it came back after about three drive cycles. The service center has now contacted technical support and sent over the diagnostic data to see if they have any further guidance.

Driving Behavior: Aside from the warning light, the car drives perfectly fine. Oil temperatures reach about 105°C during normal to spirited driving.

Has anyone dealt with this before? Any opinions on what else we should check?

Thanks a lot for your time and help!

Hello, welcome to the forum.

The Stop/start error is normal - SS is disabled if the MIL (check engine) indicator is activated.

Hope you find a resolution soon for your initial fault.

First thing I'd check is the recently installed wiring bypass.

Thank you D402, but I don't think the recent bypass is the culprit. The issue was already present before it was installed and has persisted since.

I’ve recently noticed that the fault resets itself if I cycle the ignition about 3 times once the engine is at operating temperature (100°C+). Between each cycle, I drive a short distance of approximately 100 meters and reach a speed of 50 km/h.

When starting from a cold soak, the Auto Start-Stop error triggers immediately, followed by the Check Engine Light (CEL) after the third cycle. However, repeating these short 100m drives and ignition cycles while the engine is hot seems to clear the fault.

Edited 17 April17 Apr by digibum
Defining cycle...

I suspect that the short drives and cold starts don't create the conditions where the solenoid is actuated so the ECU clears the fault after three cycles without the fault being detected.

You said that the replacing the solenoid did not resolve the fault. This suggests that there was never a fault with the solenoid so the technician moved on to check the wiring, found a fault and bypassed it which initially solved the problem. Next step is definitely to check the wiring again as this was found to be faulty before.

On 17/04/2026 at 09:36, D402 said:

I suspect that the short drives and cold starts don't create the conditions where the solenoid is actuated so the ECU clears the fault after three cycles without the fault being detected.

You said that the replacing the solenoid did not resolve the fault. This suggests that there was never a fault with the solenoid so the technician moved on to check the wiring, found a fault and bypassed it which initially solved the problem. Next step is definitely to check the wiring again as this was found to be faulty before.

It could be that the new bypass has failed for some reason. Depends how it’s been connected.

This morning, I performed a cold start, and a Start-Stop system error appeared immediately (though the Check Engine Light / MIL remained off). After a 15-minute drive, I stopped at a gas station to refuel. The vehicle was stationary for about 5 minutes. Upon restarting, I drove 10 meters to the main road and stopped; the Start-Stop system engaged correctly, and the engine stalled/shut down as intended.

After another 10 minutes of driving, I stopped in a traffic queue, but the engine failed to shut down. I checked the vehicle status menu, which displayed a Start-Stop error. Five minutes later, I cycled the ignition (turned the car off and on) about 100 meters before my destination. The start-stop error cleared, and upon reaching the parking spot, the engine shut down automatically.

After the car sat for 5 hours, I took a short trip (under 5 mins), and the Start-Stop error reappeared instantly. Following a 30-minute soak time, the error persisted on the return trip. Again, I cycled the ignition shortly before parking; the system reset, and the engine shut down normally at the destination.

Scanning the vehicle with OBD11 revealed the old P25AB00 Piston Cooling Oil Control Circuit High.

Toward the end of the day, the Check Engine Light (CEL) illuminated, and the Start-Stop system became permanently disabled.

The service center is currently in contact with Škoda’s technical support for consultation. They are awaiting a response.

They've also double-checked the bypass and used a cleaner spray on the contacts.

Interestingly, the fault did not reappear at the service center after they inspected the car, cleared the codes, and performed a 40 km test drive with over 20 ignition cycles. During their testing, the car reached full operating temperature. In contrast, when I'm driving, the error occurs very quickly—usually after just a few trips.

Will report back :)

Just a quick update to the thread, both to keep this documented for future reference and in case someone has a fresh idea or a similar experience to share.

Since my last post, the dealership went ahead and replaced the Engine ECU.

The result? Absolutely no change. I picked up the car yesterday, turned the ignition on, and immediately got the Start-Stop error. Within two ignition cycles, the Check Engine Light was back with the exact same static code: P25AB00 (Piston Cooling Oil Control Circuit High) on a cold start.

To recap, the entire chain is now 100% brand new OEM:

1. New Oil Control Valve N522 (06K115243L)

2. New Engine Wiring Harness

3. New Engine ECU

If anyone has any new insights or has seen this happen on Superb 2022 2.0 TSI 280HP, please let me know. I'm completely baffled.

Perhaps time for them to try another valve replacement.

Was the new ECU cloned from the old one. If there is a software problem it may still be there as its been copied?

Alasdair

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!

15 hours ago, Alasdair1 said:

Was the new ECU cloned from the old one. If there is a software problem it may still be there as its been copied?

Alasdair

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.

Odd it does it at cold start. Wonder if its a poor connection somewhere thats bad when cold and when warm it expands making better contact or perhaps cranking cold engine is dropping voltage too low and causing errors. Check battery voltage when cold cranking? Hope you get to the bottom of it

Alasdair

Maybe check engine bay fuse box for loose contacts/corosion/relays and all earth points you can find. as the wiring is new and so is valve.

Alasdair

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:

1. Cleared the fault code (P25AB00).

2. Turned the ignition off.

3. Turned the ignition back ON (engine OFF / no cranking).

4. 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!

Edited 21 hours ago21 hr by digibum

How many seconds was there between step 2 and 3?

If only a very short time, try repeating test but leave 60 seconds between ignition off and back on again. See if same outcome.

Are you getting 12v at N522 valve with ignition on. Just wondering if its a bad fuse or relay problem. Read the valve is supplied with 12v at ignition and ecu connects earth to operate it.

Alasdair

17 hours ago, Breezy_Pete said:

How many seconds was there between step 2 and 3?

If only a very short time, try repeating test but leave 60 seconds between ignition off and back on again. See if same outcome.

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!

It could also be voltage related.

Warm engine implies recent charging, cold engine implies the opposite.

There are about four other devices powered from the same fuse I believe, but would need your engine code to check properly. Maybe one of those other devices is pulling too much current, and causing the whole voltage supply from that fuse to dip too low during a cold start, or something like that.

10 minutes ago, Breezy_Pete said:

It could also be voltage related.

Warm engine implies recent charging, cold engine implies the opposite.

There are about four other devices powered from the same fuse I believe, but would need your engine code to check properly. Maybe one of those other devices is pulling too much current, and causing the whole voltage supply from that fuse to dip too low during a cold start, or something like that.

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!

DNFE / 2.0 TSI EA888 Gen 4 / 280 hp

A random thought and could be wrong but wonder if its corrosion or bad connector pin/socket in bottom of engine bay fuse box? Might be making good contact when warm but poor when cold thats not enough to trigger other fault codes but the N522 valve system may be more sensitive.

Alasdair

5 minutes ago, Alasdair1 said:

A random thought and could be wrong but wonder if its corrosion or bad connector pin/socket in bottom of engine bay fuse box? Might be making good contact when warm but poor when cold thats not enough to trigger other fault codes but the N522 valve system may be more sensitive.

Alasdair

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)

This is for VW Arteon SB from 08.2021 but should be the same as Superb. Check it

Will try to look for circuit info this evening.