This is the view of the ECM with the reverse/cruise module piggybacked on top
of it.
Bikers Workshop Series
Part 10; Replacing the ECM on a GL1800.
By Steve Saunders.
Having received the Service Bulletin 15 (the overheating fix) recall letter from Honda, it was determined from the VIN number of my machine that only the ECM would need to be replaced. This is the minimum of warranty work that any 2003 model will need, many other machines (especially 2001 & 2002 models) will also need to have the cylinder heads checked and/or replaced, and also to have a coolant gauge sub-harness inspected and/or replaced. The Honda distributor in Ireland was good enough to supply me with the new ECM so that I could fit it myself.
Click the thumbnails for a bigger image.
First task is to remove the top shelter. Full instructions (with photos) for shelter removal are given in the article on GL1800 CB Radio Fitting. You don't need to disconnect the battery before commencing this job, as the new ECM out of the packaging will not have been set up (initialized) before. More on this at the end of the page. If you leave the battery connected you won't have to reset your radio channels later on.
This is the view of the ECM with the reverse/cruise module piggybacked on top
of it.
After removing the two connector blocks from the reverse/ cruise module and
the three from the ECM, gently pry the tabs on the mounting housing up and slide
the reverse/cruise module out to the left.
This is the reverse/cruise module removed.
Now pry the single tab at the bottom middle of the housing down and slide the
ECM out to the left.
The replacement ECM on the left and the old one on the right. Different part
numbers and manufacturers names on the label are the only visible difference between the two units.
This is the housing with the two units removed. You can get a better view
here of the tab that locks the ECM in place. Fit the new ECM and the
reverse/cruise module and make sure all the connector blocks are firmly in
place. Before replacing the plastics, you will need to initialize the ECM. This
is crucial to setting up the unit properly from the very start. To initialize
the ECM, start the engine and allow it to warm up to it's normal operating
temperature and stay running for at least 90 seconds after. If you are not sure
what the normal operating temperature is, just wait until the fans come on and
wait the 90 seconds after that before switching off the engine. I actually
waited until the fans cut out and came on and cut out a second time before
shutting off the engine. It's very
important that you DO NOT operate the throttle during this time, otherwise you
will need to repeat the process. A Honda mechanic informed me that failure to
initialize the ECM usually results in popping sounds, erratic idling and a
higher than usual appetite for unleaded, among other things. That's it folks, new ECM installed. Replace the
plastics and saddle and away you go into the heavy city traffic, no longer
fearing to trundle along in second gear at low speeds!