FI fault code 25

Information and questions on GL1800 Goldwings (2001-2017)
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Posts: 1
Joined: Sun Jul 19, 2020 3:45 pm
Location: united states
Motorcycle: 2004 GL1800

FI fault code 25

Post by chips »

i am the new owner of a used 2004 GL1800. it has about 70K miles and i have put the last 400 miles on it. all was well until i had an FI light. i learned how to check it and found out it was #25, right hand knock sensor. the other day on my way home it bucked a few times and then the light came on and it was all i could to get home. at a stop sign i had to keep it about 1500 RPMs. when i arrived home all i had was the #25 code. the next day it started but would not idle and sounded like a sewing machine. two day later it was better however, idle was still searching. will the sensor cause this or should i start looking for a new PCM. any ideas or helpful hints.

Posts: 482
Joined: Mon Jun 13, 2011 10:11 pm
Location: Lexington, KY
Motorcycle: 2004 GL1800

Re: FI fault code 25

Post by Techdude2000 »

Sorry to say it, but nope, the rough running in conjunction with a knock sensor code points to a bad ECM(engine control module). A bad knock sensor won’t make the engine run badly at idle. This is a common failure for the 01-05 wings.
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Joined: Thu Oct 30, 2008 2:46 pm
Location: Lake Oologah Indian Territory USA
Motorcycle: 2009 Piaggio MP3 250cc

'02 GL1800 lives in Dawsonville, GA now.
My son is going to enjoy it for many years to come.

Re: FI fault code 25

Post by AZgl1800 »

I have never heard of a bad knock sensor,
probably one out there, but it is a rare duck.

the problem is a bad connection inside the ECM.
I thought I could fix that connection, but the potting compound they use is harder than a diamond.
I was not able to even make chip mark in it with hammer and chisel.

so, I found a used 2004 that hit a solid wall .....
any year from 2001-2005 will work in our 1st gen bikes.

mine is an '02.

I never had the problem of rough running like you describe, just a sorry MPG situation, other guys riding with me were getting 40 and I would get 28-32.

the new/used ECM fixed that problem.

for now, to try and get rid of that rough running.
set the bike on the center stand.
start it and do NOT touch the throttle.
allow it to run until you hear the fans cycle on/off at least twice.

that re-calibrated mine and made it run pretty good.
it always had full power, just lousy MPG results.

2009 Piaggio MP3 250cc
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