P2C90 Code After Oil Change – Check Your Oil Cap

[Fuzzy761210]

Took my 2025 in for its first oil change at 5,000 miles this past Friday.

This morning, I started the vehicle and was greeted with a check engine light. Pulled the code—P2C90. For reference, my ST is completely stock.

After browsing the forum, I saw that this code can sometimes be caused by a loose or disconnected hose in the crankcase ventilation system. Popped the hood and immediately noticed some oil splatter around the engine bay. Turns out the lube tech forgot to reinstall the oil cap—it was sitting on the cowl.

I reinstalled the cap, cleaned up the engine bay, double-checked the oil level, and cleared the code. No issues since.

Just wanted to drop this here in case anyone else runs into the P2C90 on a stock setup—check to make sure your oil cap isn’t missing or loose. It can absolutely trigger this code.

 

[STeiner]

Good to know. And another reason why I'm the only person who changes the oil on my ST. In the past, I've had "lube techs" skip changing the oil filter and also one time I caught them using cheap oil after I paid for premium synthetic. Also, it's a really good idea to double check the oil level now. Those guys are in a hurry and they just add the 6qts. If it's overfilled you are losing power, if it's under filled you are losing oil pressure. I don't trust them, especially since Ford gave us cheap plastic oil pans with plastic oil plugs. Who knows what else those "lube techs" messed up under there. I just changed my oil yesterday with Pennzoil Ultra Platinum and a Ford Motorcraft filter and it only cost me $47 and it was done right.

 

[Fuzzy761210]

Also, it's a really good idea to double check the oil level now. Those guys are in a hurry and they just add the 6qts.

yeah I checked the level, its right where it needs to be.