Passat V5 - 18256 -Please check DTC Memory of Engine Controller - P1848

[Pristle]

After the painful saga of the motor swap, she was behaving well, if not a little thirstier.

Until Thursday arvo that is. After taking the Princes St exit from the southern motorway (Otahuhu, Auckland), the temp warning light came on with a 'check coolant' warning. Temp gauge sitting rock solid on 90?. I pulled into the Z station 50m away. Switched off and check the expansion tank. Coolant level was normal by sight, but coolant was boiling through the cap.

After letting her cool for a bit I took cap off only to find two things, a broken o-ring seal and oily sludge. (something I was dreading as there'd been an issue at the shop and the wrong coolant went in). Checked the oil, clean as a whistle. No caramel. I retopped the expansion tank, warning went away and I drove home slowly. An hour later when I was going to pick up my wife the alert came back.

Flash forward to Friday, I drained the system, then flushed it through with Simple Green and a branded coolant flush. Put the right coolant in, replaced the cap. (no one seems to sell the o-ring in Auckland).

I do know that while checking for any coolant leaks I removed the intake hose between MAF and throttle body, unplugging throttle motor. After taking a phone call, I absentmindedly started the car to test for the coolant warning. When I saw that I'd overlooked refitting the hose and plugging the throttle motor in, I switched off and made the amends.

However I now have the EPC and a yellow triangle/exclamation lights coming up. The diags suggest 18256 -Please check DTC Memory of Engine Controller - P1848.

I understand this could be cleared using VCDS, is this correct? If so, can I borrow it from someone? I have the Lite version and it doesn't seem to be an option for me.

[80 Vert]

Oil in coolant points to water / oil heat exchanger. Very common to get oil in coolant yet not the other way round.
I've found removing it and pressure testing in a bucket of water the best way to test.
Re fault code yip just clear it vcds