ECM FAILURE POLL AND DISCUSSION

ECM Failure poll

  • Year 2002 thru 2007 Failure - NON Police bike

    Votes: 33 45.8%

  • Year 2002 thru 2007 Failure - POLICE BIKE

    Votes: 0 0.0%

  • Year 2008 and newer Failure - NON Police bike

    Votes: 3 4.2%

  • Year 2008 and newer Failure - POLICE BIKE

    Votes: 1 1.4%

  • Your solution: Replaced ECU

    Votes: 14 19.4%

  • Your solution: Awaiting ECU

    Votes: 4 5.6%

  • Your solution: Live with it

    Votes: 7 9.7%

  • Just looking

    Votes: 36 50.0%
  • Total voters
    72
2004 non-police, I chose both replace (because I did) and live with it (after the second one did the same as the first...); staying below 4K is working for me (I know, against the advice of some well respected members!)

1 Sep 23 update: Night before last, mistakenly exceeded the 4K rpm limit and triggered the FI light, twice. Cycled the Engine Stop switch with the clutch pulled in to reset both time, and kept riding. Just proves that the problem hasn't gone away; I'll continue to ride below the limit, plenty fast enough for me for now until I can find another inexpensive ECU. Not worth the several hundreds of dollars when the engine runs just fine (in my experience only, you do you) when the fault isn't illuminated. 20" MPGs are back up in the high 40s/low 50s at 69mph GPS / 74mph indicated on the toll road I ride regularly. Average MPG remains around 45 tank after tank.
 
Last edited:
For the wire harness swap idea I started looking at what else is different between 07 and 08.
ABS computer
ABS sensors
ABS rings
Throttle body assembly and sub harness
Oxygen sensors.

Regarding having spares in stock, that was enough to determine that I will not be looking further into this and acquiring harness and conversion necessities for a problem that might not happen and would not strand me anyway.
 
Igofar said:
I have seen a few 08 and newer PD bikes have them fail, but to be fair, they were on escort bikes that had a mess of jury rigged wiring which probably killed them.
Click to expand...
New ecu didn’t fix the 25 code, checked the 5 way tee , was clean, new knock sensors , ran a new shielded wire from knock sensor to ecu, adjusted the balancing shaft , any ideas would be greatly appreciate
 
Just out of interest - a late comment.

Here in the Uk, there have been only 2 PGM-FI variations for the ABS. model. The pre -2008 version and the 2008 and later models.

We had new models in 2008, 2009 and 2014. As far as I can make out, all had the same newer PGM-FI umit.

I've had 2 ST1300s from brand new.

The A6 always had a high pitched rattle from the engine, like feint jangling keys, when hot, accelerating hard, at higher altitude or with E10 fuel. It was pinking. Pre-ignition. So the knock sensors weren't doing a good enough job, or the ecu was ignoring it at that level.

For certain it wasn't the same degree of pinking that you get with the old single cylinder two stroke fixed timing systems.

I eventually stopped it by using higher grade fuel and curiously 10w40 fully syth oil. I found the 10w30 to be too thin in the alps.

But this engine always struggled for low down grunt when negotiating tight, steep uphill hairpins. It required first gear and a lot of clutch slip to prevent it from stalling.

In contrast, my 2009 model has always felt superb. Gruntier, no clutch slip required - just put it into first and it powers round the corners no problem - and has never pinked.

My feeling is that the A6 was designed to run a tad too lean.

I don't know if this analysis is correct, but I know I would never look at a model that was older than 2008.
 
I think at least some of it, may be attributable to manufacturing tolerances differences .
My 05 would ping on regular, frequently under more than normal load .
My 06 on regular , rarely pings under full load/ acceleration .
 
Would it be possible to take a 38770-MCS-R12 ECU along with a 2008-12 wiring harness and replace both in an 2003 to 2007?

Sounds crazy but they still make the 38770-MCS-R12.
 
MattSTlouis said:
Would it be possible to take a 38770-MCS-R12 ECU along with a 2008-12 wiring harness and replace both in an 2003 to 2007?
Click to expand...

I think it is probably possible, but I think you would need to replace all electronics. I only see one common sub harness on the parts list, and this is comparing ABS to an ABS model. The only way this would make sense (in my mind) is if you had access to a totaled 2008+ model and lots of time to compare/switch parts. Keep in mind, I don't know if there were any engine refreshes along with that new ECU.

1694638298548.png
1694638320970.png

Ryan
 
For ABS versions, the pre-2008 model has a castellated pulsar ring on the front wheel with the sensor facing down - like the one on the back wheel of all ABS models. From 2008 they have a slotted steel disk on the front wheel with the sensor facing inwards.

I haven't counted the slots and castellations and compared them to see if they have the same number, but if they are different then that is a distinct possibility for a difference in the programming of the ECM.

My 2009 model is certainly tuned differently from the way my 2006 was tuned. Whether this was simply the ECM, I don't know.

I once compared the 2009 model with the CTX1300 to see if they had adopted anything from the engine in that experiment. I noticed that the crankshaft on the CTX is different (perhaps different TDCs ??), along with a few other internal hardware bits. But the ST1300 remained the same for the bits that I compared - 2002 to 2009. Abs models. But i didn't check everything.
 
Last edited:
Alright so the 2008 and up route gothcha would be a sensor picking up something incorrect and then throwing a CEL and the problem would be worse.
2 other options.

The best part about this is my incredible luck. I test rode the bike and not FI light everything was perfect for the first 90 miles then the FI light came on with a 26. The pervious owner just used it to go back and forth to work and never saw the light. He seems very honest and has offered to pay for some of the repair parts.

1. What about a european set that has the HISS with the keys and the ignition switch?
2. I saw on another forum that a guy put the bike into diagnostic mode by jumping 2 of the wires in the diagnostic port and claims it runs normally like that. The FI light will stay on but he actually hooked up a switch to turn it off.

This is actually the first bike I have bought that I regretted.
 
The Fuel System error code table in my 2003/2004 UK workshop manual says that for reported FI codes 25 and 26 (knock sensors), the engine runs normally.

Black Tape ?
 
No problems with the ST so far, but 2003 BB has the sickness. The more commonly cited point on the RPM line seems to be 5,000 there vs 4,000 here.
[Post 92] Just wondering there on the first sentence "... engine runs normally." If it is it your interpretation from that statement in the manual, that the fault code is to notify but that the ECU [possibly in some instances] takes no corrective action?
Reading through various posts here and on the BB site there seems to be anywhere between nearly imperceptible and substantial changes in how the ECU performs when the code appears; I wonder if an isolated knock sensor detection or circuit fault alone makes no change to timing so on unless there are other problems, such as - max timing variation failed to correct - or knock amplitude signal exceeded high range value or something like that which might be attributable to other problems.
I'd also be interested in another aspect with the STs since this is likely going to be the best database and where a practical solution is found, and that is how bad is it; once the light comes on and if the bike is being driven anyway, is there any variation in [bad] performance afterward between similar ECUs.
While you can still purchase replacements [in some instances] there's accounts of replacements failing, so it may be that these replacements are old and have a shelf life [whether they are in service or not] as well. Or could it be that later runs have lower knock sensitivity thresholds.

bit of correction; it certainly makes a change to timing on knock-detection, but is that only coupled with switching to fault mode if other inputs dictate.
 
Looks like I may need to change my vote. The FI light came on on my 2005 for the first time in 8 years of ownership (at the BRG). Thankfully I was able to continue riding it and got home safely. I'm not sure it's the ECM as I haven't read the codes yet. I'm hoping it'll turn out to be something simpler, but maybe not likely. I'm very disappointed in Honda for discontinuing the part. Not sure what options I have if it turns out to be the ECM and if it's worth trying to keep an 18 year old bike going at this point.

EDIT: Read the code and it's the ubiquitous 26 :(
 
Last edited:
Another thing to consider in this is weather or not the failed ECU was in a bike that used premium or 87 octane fuel. My theory is that if it happens on bikes where the owner used lots of 87 like mine, that it may be a failed solder on the board caused by constant knock sensor readings and adjustments(which I think I might be able to fix).
 
2007 St1300 with 26000 miles. Original owner. Premium-no alcohol fuel always.
Dealer say I have ECU failure. He is not seeing any codes with a code reader, but the bike will not start. Shot of ether and it fires/runs as long as the ether lasts.
Last three weeks he's been throwing parts at the bike before deciding it's the ECU.
Looks like everyone else who has an ECU failure gets codes, but the bike still runs.
Has anyone had a failure with no codes and the bike not start?
After both me and the dealer shop searching, there is not a new ECU to be had.
I'm getting desperate for a fix.
 
Stu Padazole said:
2007 St1300 with 26000 miles. Original owner. Premium-no alcohol fuel always.
Dealer say I have ECU failure. He is not seeing any codes with a code reader, but the bike will not start. Shot of ether and it fires/runs as long as the ether lasts.
Last three weeks he's been throwing parts at the bike before deciding it's the ECU.
Looks like everyone else who has an ECU failure gets codes, but the bike still runs.
Has anyone had a failure with no codes and the bike not start?
After both me and the dealer shop searching, there is not a new ECU to be had.
I'm getting desperate for a fix.
Click to expand...
Your dealer is an idiot, and throwing parts at your bike to generate revenue etc.
If it’s not throwing a code, and it runs with starting fluid until it runs out, it’s probably something much simpler like a fuel pump issue etc.
I would start by getting your bike away from that shop, and checking the five way tee first.
Also, just because you HEAR the fuel pump pressurize, does not mean it’s holding pressure.
A $65 dollar fuel pump would be much cheaper than a seriously expensive ECU that I’m betting the dealer knows where one is sitting on a shelf somewhere that he would love to charge you for.
Standing by he white courtesy phone.
:WCP1:
 
You must log in or register to reply here.
Back
Top Bottom