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ECM Surge - Keeps Burning [message #301685] Sun, 02 February 2020 09:58 Go to next message
lhaluciol is currently offline  lhaluciol   United States
Messages: 1
Registered: February 2020
Karma: 0
(1) Club Racer
Hi Guys,

This thread is for electric gurus! I've replaced the ECM of my 2004 CBR600RR twice now, something is surging and keeps frying them.

It all started with very poor idle, very rich conditions and 4 errors on the MIL System:

1 Blink: MAP Sensor Malfunction
7 Blinks: ECT Sensor Malfunction
8 Blinks: TPS Sensor Malfunction
9 Blinks: IAT Sensor Malfunction

I went through all steps to troubleshoot these errors in the service manual: continuity, voltage measures, resistances etc. Most results end with "Replace the ECM".
When I should read about 5V coming out of the ECM, I read 0V.

So, I replaced the ECM. The bike started right up and run great for a few miles with no more error codes...until it died. Again.

FI MIL Light blinking like before. Back to square 1.

I'm guessing that something is surging the ECM, like a ground or a solenoid shorting. Bypassing any fuse. The rectifier is under specs and the stator sends 13.9V at 5,000rpm. All good there.

I'm quite mechanically inclined but this time, I'm baffled...

Any help is greatly appreciated!

Thanks guys.
Re: ECM Surge - Keeps Burning [message #301686 is a reply to message #301685] Sun, 02 February 2020 11:58 Go to previous messageGo to next message
Kakugo is currently online  Kakugo   Italy
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Registered: August 2003
Location: Throne of Tragedy
Karma: 35
(18) Geoff Duke
It's always very hard to make a diagnosis over the Internet, but given the symptoms I'll go out a limb and say you have the mother of all shortcircuits in the main wiring harness.

If you have a California model there's a remote possibility the heating element in one of the two O2 sensors is the cause of that short, but generally these things die a dignified death and don't take anything else with them. The possibility however exist, as remote as it is.

On the other hand that gaggle of unrelated error codes make me lean very heavily toward a short in the main wiring harness: you have three unrelated sub-harnesses giving troubles all at once. What are the chances? think
There's no fuse or breaker circuit protecting the ECM (believe it or not), so the problem is in the main wiring, most likely on a hot wire or on a ground line.

I've seen similar problems on period Honda's in the past, mercifully without ECM damages, and they are generally caused by main wiring damages, especially near the frame where the peeled wires can be conveniently grounded and make a fine mess. Bikes with aftermarket alarms in particular have a ton of wiring issues because Honda wiring harnesses don't like being cut and spliced but on a bike 16 year old and with an unknown history anything can happen. Confused
Re: ECM Surge - Keeps Burning [message #301687 is a reply to message #301685] Sun, 02 February 2020 12:30 Go to previous message
Tomthumb is currently offline  Tomthumb   United Kingdom
Messages: 630
Registered: January 2016
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(6) Moto1 GP Racer
Totally agree with @Kakugo , the faults that are showing are "non essential" and have a fail safe "limp home" mode so engine would still run, as Kak says you have got to look for a fault that wont give a fault code and a wiring problem, have you done any work to the bike recently , does it have a PC , replaced anything to do with the wiring
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