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Gen 1 error code 21 troubleshooting

Tech section strictly for the FJR. Everything from oil changes & suspension setup's to removing sheep hair from hard to reach places on the bike so that your wife never finds out.
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PJ4863
Casual Rider
Posts: 99
Joined: Wed Feb 22, 2017 9:32 pm
FJRModel: 2004
x 4
x 92

Gen 1 error code 21 troubleshooting

Post by PJ4863 »

Ug.. when it rains it pours. I finished re-wiring my rostra cruise control switch, went to go start the bike to trouble shoot any issues.. and error code 21 pops up. This is on a Gen 1 2004. Bike started, cooling fan came on right away. Last couple of times I took the bike out, i noticed it was running cooler than usual, but didn't notice the fan running constantly. To be fair, I also didn't check. To throw more gas on the fire, I can't find my service manual anywhere.
1. where is the temp sensor?
2. I'm assuming the temp sensor doesn't run through the neck of the frame, and the fan issue is coincidental to the cruise control issue?
3. Pray its not a bad ECU :(

Any ideas? Help?
PJ4863
Casual Rider
Posts: 99
Joined: Wed Feb 22, 2017 9:32 pm
FJRModel: 2004
x 4
x 92

Re: Gen 1 error code 21 troubleshooting

Post by PJ4863 »

Never mind.. Mostly. I'm a genius in my own mind. I think I found the temp sensor, its on the right hand side of the cooling pipe that comes out of the top of the head. I broke the clip on that connector at a tech day like 5 years ago and messing with it slid it off jjussst enough. Made sure it was on tight, error code went away, fans ran normal. Pulled it back off, error code is back with the fans on. Put everything back together so I can ride it later :)
raYzerman, HotRodZilla, and FJRoss loved this
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raYzerman
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FJRModel: 2010 Honda CBF1000FA
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Re: Gen 1 error code 21 troubleshooting

Post by raYzerman »

Glad you found it... if that was a Gen2 or 3, bike won't start with the coolant sensor connector not connected.
Keep yer stick on the ice........... (Red Green)
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