Error Code 203 521110

[PatrickKolby]

Our 2021 212SE just gave out this code 203 521110. After searching other posts it seems it’s the post cat O2 sensor. Roughly $175 online. Going to check with the dealer and see if I can warranty it without having to tow the boat to them.

Anyone have experience with this code? It’s a California emissions part so I doubt any harm to be done if running without fixing right away.

 

[PatrickKolby]

Looking further into this a couple of issues.

New small amount of water in bilge. I’ve fixed all the previous culprits like clean out hatch and anchor locker.

Since I’m in salt water I can see small amount of salt residue on parts of the engine which makes me think the intermittent bearing is leaking causing the spray up.

Looks like a dealer visit is a must at this point.

 

[Cobra Jet Steering LLC]

I would suspect the water in the hull is being slung around by the vibration dampener wheel behind the engine it is a new boat so unless someone blew the seals using a grease gun on it there should be nothing wrong with it. To see if it is leaking put the boat in the water not operating just floating and watch the area behind the engine for water coming in the hull.

 

[PatrickKolby]

I would suspect the water in the hull is being slung around by the vibration dampener wheel behind the engine it is a new boat so unless someone blew the seals using a grease gun on it there should be nothing wrong with it. To see if it is leaking put the boat in the water not operating just floating and watch the area behind the engine for water coming in the hull.

Thanks for the reply. Going to check today and will report back.

 

[PatrickKolby]

Okay. I moved the good post cat O2 sensor over to the side causing the 203 code and bingo code went away and appeared on the swapped side.

Couldn’t figure out where the water is leaking from though. Boat sat in the water for an hour not running and no leaks. Must be coming from somewhere once underway.

Going to order the new sensor today. I believe this is the part number:

6DE-8592A-00-00

Can anyone confirm this?

 

[Cobra Jet Steering LLC]

check all the hoses and the seal around the cap of the boat where both parts are put together use a hose and aim up under the ridge of the boats rub rail and see if water is coming in between the two halves of the boat.

 

[PatrickKolby]

Just did this and yes. Water coming in around the stern and the port side on the rubrail. I guess then the water is getting sprayed around a bit in the engine compartment once it leaks in from the rub rail.

Seems like a job I can do since trailering the boat to the dealer and waiting on them might not be worth the hassle.

Thoughts anyone?

 

[Cobra Jet Steering LLC]

That is actually a warranty issue due to poor workmanship, those seams are supposed to be water tight that really sucks but I told you to check it because it is a common problem.

 

[PatrickKolby]

Update!

Replaced the post cat O2 sensor today and bingo no more code and after 4 clean starts the CEL as expected went away.

Also, pulled the rub rail and used 4200 to seal it up. Def some questionable work done by Yamaha.

Just got back from taking the boat out and it was bone dry. Not a drop!

Also, that faulty O2 sensor def had the boat running a bit rough.After replacement it’s smooth as butter.

 

[PatrickKolby]

Ran the boat all day today. Not a single drop of water anymore.

Zero water in the boat is a good feeling!