How do you access the coolant temperature sensor and its wiring harness?


BlueShift

New Member
Hey everyone, I'm getting a diagnostic code 21 on my FZ6R which means that either my coolant temperature sensor is bad or the wiring along the way to it has an issue.

I got my hands on the service manual but its not clear from the manual how to actually access the coolant temp sensor or where the wiring harness(es) are. I'd like to first just check the wire harness connection and see if there's just some dirt or corrosion there.

Has anyone replaced this part before or at least know where it is or where the wires connect?

Any help would be greatly appreciated.

Thanks!
 

alaskanflyboy

Premium Member
Last edited:

BlueShift

New Member
You say you have a service manual so check 8-73, item 12. The information on inspecting the sensor is on 8-92. The sensor location is on 5-16, installed in the cylinder head on the backside between the #3- and #4-cylinder bores. If you check bikebandit.com for your bike, the washer and sensor are item #1 and #2 respectively under Electrical>OEM Parts>Electrical 1. Even if you pull the sensor just to test it, you'll at least want to replace the washer with a new one as a best practice. No need to create a coolant leak cheeping out on a part that costs less than $4. If you've done spark plugs, its all but removing the airbox and that damned baffle under it. Hell, you might even be able to get on it just removing the rider seat and leaving the tank be, but I'm not 100% on that. Judging from the diagram though it's going to be directly below the tank just above the oil cap level — which is why I almost think you might see it once the seats off since the tank shouldn't be in the way. Maybe even just remove the right-side triangle piece under the seat and see if you can get tools on it.
Thanks, yeah, I've looked at that diagram and searched through the manual PDF for "coolant temperature sensor" so I know where its located on the engine. The thing is, I don't know the best way to access it still. Am I going to need to lift the whole engine out or is it possible to get to it another way?

The other thing is I'd like to check to make sure its not just a wire harness connection issue before I buy a replacement sensor. While the service manual has great electrical schematics showing how the electronics are connected, it doesn't do a good job showing where the wiring and harnesses actually are on the bike.
 

alaskanflyboy

Premium Member
Last edited:

BlueShift

New Member
I plan to do some maintenance on my bike tomorrow. I'll look at mine. Given that it appears to be on the back of the cylinder head, I expect it to be just under the rear edge of the tank between the black triangle pieces under the seat. I'll be pulling the seat to get at my battery anyway. I'll let you know what access I see.

As for testing, the manual has testing criteria on 8-92. If you've got a multimeter, metal pot you don't care has coolant in it, a hot plate, and a thermometer, you're good to go.
Awesome, thanks a ton. Yeah I figured it was somewhere around there and am hoping I can access it just by tilting up the tank.

And yep, I plan on testing it when I can get it out. I know that the sensor isn't working in the bike currently because it always just says "Lo" even if I just had the engine running though again it could just be a wiring issue.
 

alaskanflyboy

Premium Member

BlueShift

New Member
I found it. I was wrong about the placement. I forgot how far the seat is back from the engine. You might be able to get to it just removing the right side fairing as there's a bit of room, but otherwise, it's right below the airbox. On my '09, it's a green connector and the probe is brass.

I took this photo just with just the right fairing off.

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Awesome thank you so much! It won't take me long to get the airbox out and I need to check my spark plugs anyway so I will investigate the coolant temp sensor then.The side fairings are actually more of a pain for me to take off because of the ridiculous amount of LED accent lighting I've outfitted the bike with. Anyway thanks a lot for the info and picture, I'll update this thread with more pictures of mine and procedure when I'm done.
 

alaskanflyboy

Premium Member
Last edited:


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