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05 Honda GL1800 My bike starts and runs great, but only for a few miles. Within first 10 miles I get an F1 code on dash. Will not idol. Took the bike to the dealer, diagnoses, advised bike presents with a code 25, indicating right knock sensor. Technicians note: indicate "code 25 for a bad ECM module," so obviously this is a very expensive repair.

I've also been advised that the problem might be caused by a inexpensive ($80.) control module (not sure which one) by another Honda dealer.

Obviously I'm frustrated, any insight/input you can give me would be greatly appreciated. this is my first post so I'm hoping for some good feedback. thank you. Jusstan
 

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DSI Keeper
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Normally a failing knock sensor will not cause the idle problems you are describing. Looks like a new ECM is in your future.

Found one on ebay but no idea whether it is a good one or not.

 

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GL1800 Doctor
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05 Honda GL1800 My bike starts and runs great, but only for a few miles. Within first 10 miles I get an F1 code on dash. Will not idol. Took the bike to the dealer, diagnoses, advised bike presents with a code 25, indicating right knock sensor. Technicians note: indicate "code 25 for a bad ECM module," so obviously this is a very expensive repair.

I've also been advised that the problem might be caused by a inexpensive ($80.) control module (not sure which one) by another Honda dealer.

Obviously I'm frustrated, any insight/input you can give me would be greatly appreciated. this is my first post so I'm hoping for some good feedback. thank you. Jusstan
Welcome to the board! Forget the other dealer, there’s no $80 module that will cause this. It’s your ECM.
 

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Discussion Starter #4
It seems like the ECM is what I need. But, no one seems to have one in stock.
Got any ideas on where I could get one?
 

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Discussion Starter #6
There are a few companies who say they can rebuild these ECM with a quick turnaround at a fair price. Anybody got an opinion on that?
 

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I have not heard of that for these ECMS, but if you can't find a new replacement, it might be worth a call to see if the ad is generic or if they really have done the early wing. We will likely end up going to the aftermarket eventually because Honda seems to have decided not to. It would seem to me that it is fast becoming a niche that needs to be filled.
Richard
 

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Vendor
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05 Honda GL1800 My bike starts and runs great, but only for a few miles. Within first 10 miles I get an F1 code on dash. Will not idol. Took the bike to the dealer, diagnoses, advised bike presents with a code 25, indicating right knock sensor. Technicians note: indicate "code 25 for a bad ECM module," so obviously this is a very expensive repair.

I've also been advised that the problem might be caused by a inexpensive ($80.) control module (not sure which one) by another Honda dealer.

Obviously I'm frustrated, any insight/input you can give me would be greatly appreciated. this is my first post so I'm hoping for some good feedback. thank you. Jusstan
Code 25 means that a fault occurred in the right knock sensor circuit. The circuit consists of a right knock sensor, an ECM, and a main wire harness. The knock sensor is the one that is about $80.

Did the dealer give and ETA on the ECM ???
 

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Discussion Starter #9
Code 25 means that a fault occurred in the right knock sensor circuit. The circuit consists of a right knock sensor, an ECM, and a main wire harness. The knock sensor is the one that is about $80.

Did the dealer give and ETA on the ECM ???
I did not ask because the price was so high ($1800~) and the service was even worse.
 

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I have never had a bad ECM but I have had the code 25, with the fuel injection light on the bike had a slight hesitation and fuel mileage went down about 4 mpg but otherwise it ran fine. Many folks were saying a new ECM was what I needed. Well since I already had a spare ECM that I had bought used for $100 that’s the first thing I tried, at first I thought it was fixed but a mile down the road the red fuel injection light came on again. So I finally ordered 2 new knock sensors and installed them, the problems completely disappeared and MPG returned to normal. That was a year ago and the bike is still running perfect, I put another 300 miles on it a couple days ago.
 

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I have never had a bad ECM but I have had the code 25, with the fuel injection light on the bike had a slight hesitation and fuel mileage went down about 4 mpg but otherwise it ran fine. Many folks were saying a new ECM was what I needed. Well since I already had a spare ECM that I had bought used for $100 that’s the first thing I tried, at first I thought it was fixed but a mile down the road the red fuel injection light came on again. So I finally ordered 2 new knock sensors and installed them, the problems completely disappeared and MPG returned to normal. That was a year ago and the bike is still running perfect, I put another 300 miles on it a couple days ago.
That "red fuel injection light" as you call it is actually called "fault indicator" (FI).
 

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GL1800 Doctor
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I did not ask because the price was so high ($1800~) and the service was even worse.
Geez! For that kind of money you should at least be getting a reach-around! :oops: If you want to confirm whether it’s the ECM or the knock sensor circuit, swap the knock sensors side to side and ride it again. If it throws a 26 code, you have a bad knock sensor. If it throws the 25 code again, you have a bad ECM or wire from the knock sensor. I’ve only seen one bad knock sensor wire in the 16 years of riding and working on these 1800s.
 

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Discussion Starter #14
Geez! For that kind of money you should at least be getting a reach-around! :oops: If you want to confirm whether it’s the ECM or the knock sensor circuit, swap the knock sensors side to side and ride it again. If it throws a 26 code, you have a bad knock sensor. If it throws the 25 code again, you have a bad ECM or wire from the knock sensor. I’ve only seen one bad knock sensor wire in the 16 years of riding and working on these 1800s.
At this point I think I'm just going to buy a new ECM and be done with it. Thank you for your help.
 

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I just read an old post for Fred H. who is a Goldwing expert. He suggested removing the ECM and cleaning the contacts before reattaching them. Another post I read said the same thing. He cleaned the contacts with contact cleaner and added dielectric grease as well which worked on his bike.
 
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