Engine Temp Sensor - YDS Code 15

[VitaminSea]

Hey braintrust, need some guidance here..

2012 SX210 with the MR1 motors.
Been trying to solve for an engine overheat alarm for the last few months on my port engine

Have replaced the following-

Engine Temp Sensor
Thermo switch, both engine and exhaust
And have swapped the intake sensor between the motors.

Also just had the motor pulled and water jackets cleaned to rule out blockage (that was when the issue was intermittent after replacing the sensors).

Initially the issue was intermittent, however it’s now persistent on the YDS, as in clear it and it pops right back up.

Just floating, engines off - the YDS was bouncing around with readings between 90C and 106C. YDS indicates the fault as Irregular.

Any suggestions on what to check/how to problem solve for this? The sensor is somewhat or a pain to get to as it’s in the block under the headers, else I would try to swamp them now (on the lake at the moment).

 

[VitaminSea]

@Neutron or others. (Neutron’s recent post about a lose connection got me thinking here).

How does one remove and look to repin/crimp this connector? I noticed one of the wires moves slightly in the harness. Also, is there a way to get the harness to disconnect from the plastic backing that is tapped to the wire loom?

this is the engine temp sensor.

 

[Weeb]

you can buy terminal pin removal tools on line.

 

[Brad_Ct]

Try putting some dielectric grease on the terminals

 

[VitaminSea]

Thanks for the feedback. I wasn’t certain what the tool was called and the procedure. I found this video, and it looks pretty straightforward. Will try that when I am back at the boat with a dab of dielectric grease.

 

[Dixemon]

I would suspect a bad connection as well. Have you vetted the thermostat yet?

 

[VitaminSea]

I would suspect a bad connection as well. Have you vetted the thermostat yet?

just checked the original Thermosensor and the resistant at 68F and 212F where within spec. Gonna try to reinstall that (say try as I had a mechanic do it the first go around l), and check the wiring/pins next time I am at the boat.

This last time out was the first time I recall actually getting YDS to show an error 15 - Thermosensor . Previously it was 252 - overheat.

 

[VitaminSea]

Made it back to the boat this evening, swapped out the thermo sensor and the persistent error code of “15” was able to be cleared via YDS. Idled the engine for 30 seconds or so (no hose access), and all seemed well (sensor was progressively showing an increase in engine temp). Got the removed (new) thermosensor home, and can’t get a single continuity reading from it. Ran out of time/daylight to water test today, so hopefully will be able to get back out one day this week. Fingers crossed that the initial intermittent OH was due to blockage in the water jackets, and the bum sensor didn’t help in the problem shooting…

 

[VitaminSea]

Had a free afternoon and was able to get the boat out today. It appears all is well! Fingers crossed its good for the summer!!!

 

[Dixemon]

Awesome news! hats off to your persistent troubleshooting, I know how painful that can be. when they pulled the motor to clean the jackets, how far did they tear it down? Just pull the heads/manifold and manually clean? I'm curious of what their process is for doing that.

 

[VitaminSea]

Awesome news! hats off to your persistent troubleshooting, I know how painful that can be. when they pulled the motor to clean the jackets, how far did they tear it down? Just pull the heads/manifold and manually clean? I'm curious of what their process is for doing that.

Thanks, it was really bugging me, and the last thing I want to do is take a problematic boat out with the family or friends on board!!

I didn’t get to see the broken down motor - but I believe it was as your suggested, the heads and manifold. Only parts I was aware of were the two gaskets (manifold and head), and there is a note about a corrosion dissolver (however I am not sure what was used). There was mention of an air compressor as well. I know all the oil was drained, and I believe the oil cooler was addressed as well.

I have had the boat since 2019, and I have always flushed the engines after each outing (~7-10 mins each) & use salt away/off even if I wasn’t in salt/brackish water. Can’t speak for the PO and his routine. I have also tried on 3 occasions a closed loop flush - large tote under boat/pump, sump pump hooked up to hose to circulate while engine is running, occasionally adding ice blocks to the sump to keep the solution a reasonable temp, and pinching off the supply side from the bump to help ensure the solution had to cycle. I have tried 2 gallons of vinegar with some dawn diluted with ~15 gallons of water, I have tried the Hammerhead descaler, and I have tried just using a solution of Salt-Away. Generally after ~30 minutes, I would find some sediment in the bottom of the tote, but nothing significant.

 

[Dixemon]

That makes sense, did they give you any feedback as to the amount of debris that was removed or if it seemed if that was the underlying issue. I am a salt water boater as well, and have diligently salt away rinsed the boat after every outing. I guess that boat was already 7 years old when you bought it, so there's no telling how well it was flushed, or how many sandbars it hit.

 

[VitaminSea]

The debris seemed to be the issue, as I have the original thermosenor back in the block (it tested within the tolerances provided in the service manual). What was explained to me was that the build up was not allowing water to efficiently flow through out the block, trapping water by the anode & temp sensor. I had a decent stream coming out of the pissers, but apparently there was some water that just couldn’t exit from the bottom of the block quick enough and the senor was triggered.

Here are a few photos of the before.

 

[Dixemon]

That really makes me think more and more about installing strainers in the cooling lines. Glad your back out there, thank you for sharing the info.

 

[Avega]

Hello, I have a 2018 sx195 with probably an engine temp sensor issue. I see you replaced yours. Where is it located? And does it have a different name for the part. I’ve tried searching in partzilla and can’t find for my boat.

 

[VitaminSea]

Hello, I have a 2018 sx195 with probably an engine temp sensor issue. I see you replaced yours. Where is it located? And does it have a different name for the part. I’ve tried searching in partzilla and can’t find for my boat.

Sorry to hear. I haven't worked on a 1.8L SC motor, so not 100% sure where all of the sensors would be. Here are two (#13 and 15) The service manual will provide some guidance on how to verify if they are working within tolerance. Good luck with the trouble shooting!

https://www.partzilla.com/catalog/yamaha/boat/2018/sx195-rp1800bt/electrical-2

 

[Avega]

Sorry to hear. I haven't worked on a 1.8L SC motor, so not 100% sure where all of the sensors would be. Here are two (#13 and 15) The service manual will provide some guidance on how to verify if they are working within tolerance. Good luck with the trouble shooting!

https://www.partzilla.com/catalog/yamaha/boat/2018/sx195-rp1800bt/electrical-2

View attachment 220721

Thanks for your reply. I literally just ordered both parts before seeing your reply. I’m glad to see I made the right choice! Hopefully it does the trick.

 

[HawaiiBreeze]

I'm late to this post but have a question. 1.8's have anodes built into the block that can be removed. Is it possible to remove the anode, inspect it and the hole to get a hint of the conditions present in the bottom of the block?