Need Help High Coolant Temperature

musti

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Hello Everyone,

Hope all are well an safe.

Today, after my bike was sitting idle for more than 1 month, when I took it for a ride, I saw the High Coolant Temperature error being displayed on the dash. I opened the fairing and noticed that the fan didn't come on after it crossed the usual bars on the temperature side.

Here is what I did:

I first checked the fuse, and that was good
I then checked the relay. Now which one you ask me, I saw a few YouTube videos and found this relay highlighted in the image, to be the one. I tested it, and it actuated when current was supplied

Now I connected the torque app to see if I could monitor the coolant temperature, and sure enough, the coolant temperature creeped up to 95 degrees Celsius, and the fan never actuated.
I then turned to the coolant water temperature sensor. Here is what I understand:

If the temperature is displayed on the Torque app, which means the temperature sensor does send the signal to the ECU

However, when I unplugged the sensor, the fan activated in full speed. The fan came on as soon as I turned on the bike. It remained on, even when the bike was cool

Does this mean that the coolant water temperature sensor is shot? Do I need to replace the coolant water temperature sensor?

Any help and advise will be appreciate.

Thank you.
 

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Formula390

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The water temperature sensor has three wires, and is item B21 on the wiring schematic. It has a pink/blue wire in and yellow/white wire out, and that splits and goes to the ECU and instrument panel. It could be the connection to one or the other is the problem. I don't know which one would be providing the info to the canbus... But might be why you see something on torque but the fan isn't responding correctly. I would start there. The manual doesn't have an outlined test procedure but I've always tested them with a multi meter and boiling and cold water. It will either change resistance or make or break continuity. So should be easy to test the sensor. There's only the one coolant temperature sensor. I thought there might be two as I had it in my head there's two temp websites, but the second one is for air temp on the intake temp and manifold pressure sensor. Chase the pink/blue wire on the ECU pin 30 with continuity to the temp sensor, and then the output of the temp sensor via the yellow/white wire for continuity to the ECU pin 44 and pin 16 for the dash. It sounds like the temp sensor might be good, but test it anyway. I would think that given the tests you've done already, that it would have to be either the switch or the wiring.
 

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musti

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@Formula390

Thanks a lot of giving me the hint. I was able to search and download a service manual for the 390. This allowed me to look into this more.

Firstly, the radiator fan relay was the third one as shown in the image attached.
Secondly, I was able to figure out the wiring diagram from the coolant water temp sensor, to the ECU, to the fan fuse, to the fan relay to the radiator fan, image attached.
Thirdly I was able to check all the continuity across the harness. They all looked fine - I'm uploading the video on YouTube, I will make the link available soon.

The continuity to the instrument cluster, I assumed it worked, that is why the temperature bars on the ash kept going up.

@Formula390 What do you suggest I should do now? Do you think it is still the coolant water temperature sensor that needs to be replaced?

Thanks for the valuable support.
 

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Formula390

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@Formula390
Firstly, the radiator fan relay was the third one as shown in the image attached.
Secondly, I was able to figure out the wiring diagram from the coolant water temp sensor, to the ECU, to the fan fuse, to the fan relay to the radiator fan, image attached.
Thirdly I was able to check all the continuity across the harness. They all looked fine - I'm uploading the video on YouTube, I will make the link available soon.

The continuity to the instrument cluster, I assumed it worked, that is why the temperature bars on the ash kept going up.

@Formula390 What do you suggest I should do now? Do you think it is still the coolant water temperature sensor that needs to be replaced?

Thanks for the valuable support.
OK I might have missed that the instrument panel was showing temperature bars if that was written. If you are getting signal to the panel, and it's climbing as temp rises, then I would THINK that the temp sensor is OK.

I did just remember that the nut on the impeller on the water pump also has been known to back itself off, and if that happens, you'll also get a high temp warning! So I might have sent you down a wiring rabbit hole when I should have through to have you check that as well. If that's it, it's an easy fix at least of just pull the cover, put some blue loctite on the nut, and screw it back on. So next I would check the following:
1) Water Pump: Verify the nut is still on and the impeller is in good shape. If the impeller for the water pump fell off, it wouldn't be moving any water through the cooling system.
2) Stuck Thermostat: If you have a stuck thermostat or it's only partially opening, it could also be stopping coolant from cycling or not flowing fast enough. The test process for that is more complicated but might be easiest to just pull the thermostat completely and see if it's still getting hot. While you are in there, try and test flow test the radiator / flush it out. You should get a decent amount of water out of the radiator based on however much water you pour in it.

Also, I made an assumption that the coolant is topped up and that the system is fully bled of air. That can cause a high temp. Looking at the video, I'm not seeing coolant in the bottle, but it might just be that the system is cold, or you may have water in there so there's no Orange (or green) color to see in the opaque reservoir.
Coolant_Level.jpg
So this MIGHT be something as simple as low coolant. I realize I didn't initially list that as a potential source of the problem, but it's a possibility.

I don't see you saying you tested the sensor, but if the temp bars on the cluster are climbing, it seems like it's working. Still, it's a good idea to test either on the bike by unplugging it and checking for either continuity changing on/off with heat or resistance level changing with heat. I don't know which way the RC ECU looks but I would suspect it would be either variable resistance (or variable voltage) from the sensor to the ECU and Instrument Panel... but at this point, I'm thinking it's the nut on the water pump impeller.
 

Formula390

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It's part #13 that's the water pump impeller nut. The whole kit is part number:
90135055110 - WATER PUMP REP. KIT DUKE

but you may only need the gasket and a new nut if you can't get the old ones to work. Those are part numbers:
90135053000 - WATER PUMP COVER GASKET
90135058000 - DOME NUT WAPU-WHEEL
water_pump_nut-13.jpg
 

musti

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@Formula390
So I spoke to an acquaintance who works that the KTM service center, and he suggested, from his experience, that it might be the water that must've sipped in to the dashboard console that might be causing malfunction. My dashboard is is screwed from the last time I checked it. The display is not correct and that is when these problems started to occur. Therefore I am coming to the a similar conclusion.

Monsoons are currently heavy here and will have to wait for sometime till the rain simmers down. That way I will open the dash and dry it out and then see what is going on.

I will keep you posted. I much appreciate your feedback.
 

musti

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Awesome news as of right now!!
The fan finally actuated.
Since all connections were positive and since the fan motor was also spinning, I had suspected nothing less but water seepage in in the dash that might be causing failures.
Here is what I did:
I simply opened the console and let the bike running for 10 minutes, so that it would bring up the coolant to 96 (going to 97) and guess what... the fan is alive.
I let the fan run till the temp dropped to 89 while the bike still kept running. the temp creeped up back to 96 going to 97 and the fan actuated again. I am so grateful for this.
The dash also considerably has less pixel streaks (after water seepage)
Now that everything is working fine, I've order the new console cover to replace the one that I'd fix using engine gasket bond.
Thank you all for the support and feel free to reach out for any further questions or concerns.

Case resolved!
 

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KTMasean

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Awesome news as of right now!!
The fan finally actuated.
Since all connections were positive and since the fan motor was also spinning, I had suspected nothing less but water seepage in in the dash that might be causing failures.
Here is what I did:
I simply opened the console and let the bike running for 10 minutes, so that it would bring up the coolant to 96 (going to 97) and guess what... the fan is alive.
I let the fan run till the temp dropped to 89 while the bike still kept running. the temp creeped up back to 96 going to 97 and the fan actuated again. I am so grateful for this.
The dash also considerably has less pixel streaks (after water seepage)
Now that everything is working fine, I've order the new console cover to replace the one that I'd fix using engine gasket bond.
Thank you all for the support and feel free to reach out for any further questions or concerns.

Case resolved!
That is great news musti.

A question: where do you order these console covers?
I will be in the market for a few of these.
To protect your printed circuit board you may want to cover it in hair spray.
Obviously, it needs to be off the power supply when spraying it.
Can you give me a quote on the dash covers?
 

musti

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That is great news musti.

A question: where do you order these console covers?
I will be in the market for a few of these.
To protect your printed circuit board you may want to cover it in hair spray.
Obviously, it needs to be off the power supply when spraying it.
Can you give me a quote on the dash covers?
@KTMasean
I've sent you a direct message.
Cheers
 
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