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Intake temp sensor issue

R
Apr 7, 2009
11
0
1
Abbotsford B.C.
I'm not usually one to ask questions that have be answered before that's what the search function is for. But...

Before i start:
Just bought the sled im new to 900's (know lots about previous gen 800's have 2 of them im not new to fixing sled's that for sure.)
05 rmk 900
Custom cold air by PO
Slp can, pipe, head, etc.
I seem to be stumped on my CEL issue. Three flashes of the CEl according to you guys is intake air temp sensor. Pulled the sensor tested resistance at room temp, it was in the 9.7-10.3 range. Then heated it from a distance with a heat gun, temp went up. Seems to be functioning according to my tests. Next i assumed wiring, tested resistance of each wire from sensor back to the ECU, 0.01 and 0.01, close enough to zero for me to say they're good.

The problem:
Sensor seems good, wiring checks out. Whats going on here? Takes a good minute of idle from a cold start for the sensor to throw the CEL. Also was intermittent last ride, sometimes its on sometimes its off. Really stumps me. I have one plug going to the hood that's a bit melted (maybe touched the pipe?) The smaller of the 2 only about 5 wires on it, I'll get a picture of it after dinner when i go to work on the sled again. According to the service manual wiring diagram that should be the plug that sends the temp signal to the MFD, correct? So if that wire is broken or melted, would that set the CEL off, or does the ECU send the CEL signal to tell the light to come on? The melted plug seemed to still be functioning as i did the heat gun test with the volt meter on the unhooked sensor, and held the heat gun to it, while hooked up to the sled with it running and watching the temp on the MFD change.

The sensor wires were extended because of the position of the cold air intake and the sensor was hard wired in. Would that make a difference versus a plug? I doubt it but you never know. I picked up a plug to wire it in properly anyways.

If i can't figure this out tonight I'll get my dad to take it in to the dealership tomorrow (of course the one Saturday i have to work). They should be able to hook it up and see what's wrong but its gonna cost me. Is it possible this was a one time code and the ECU keeps bringing it back up and i may just need a reset to clear the codes? Can i do this myself without a digital wrench ( you know the backyard DIY way? ) or do i have to take it to a dealer?

I've given you as much as i can think of, 900 guru's this is the time for you to jump in, i'd really like to ride it on sunday!!

I'll get pictures of all the stuff i was talking about to use as references to figure this out.

Thanks, Alex
 

Newfusion900

Well-known member
Lifetime Membership
Oct 13, 2011
433
80
28
34
Blain, Pa
All sensors read through a change in resistance so having the wires hardwired and extended may be causing your problem but I'm not sure on that. The check engine light will only flash when there is a problem, once the problem is fixed you won't see it again so sounds like something is still not right.
 
R
Apr 7, 2009
11
0
1
Abbotsford B.C.
Thanks, I've determined i have a bad ground somewhere, because now i have a CEL for throttle position sensor. And it's not constant, the light comes and goes. Mainly if i rev it up a bit (the engine vibrates more) then the light comes on.
 

Newfusion900

Well-known member
Lifetime Membership
Oct 13, 2011
433
80
28
34
Blain, Pa
While you are messing around with connections and grounds it would be a good time to clean and protect all of the connections with anti corrosion grease.
 
R
Apr 7, 2009
11
0
1
Abbotsford B.C.
Problem Solved!

Connector going to the ECU had a bent ground pin, just slightly making bad contact, clean and straightened all the pins and loaded it up with dielectric grease and its good to go!

Hopefully anyone else having these issues will check this first before buying new sensors like i almost did.
 
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