That’s my boy
Can I use a ecu that has the last three digits different then the stock one.
- Thread starter Raia
- Start date
OP
OP
Thanks for the info.That’s my boy
aniwack
Site Supporter
Thanks for the link. It disappeared into the archive of history!!
Hello Aniwack. It appears I have a bad L01 on a 2005. Pardon my asking, It looks like your sentence is saying greater than 2005 can use A31, though your showing a less than sign. Do you mean 2005 through 2007 can use the A31? If so, can you give me some insight how you came to know this? It's a good bit of cash to layout... Thanks for the help!
Last edited:
- Joined
- Nov 4, 2018
- Messages
- 833
- Age
- 79
- Bike
- GL1800, ST1300
IF THIS IS TRUE, THEN WHY DID MY '07 COME WITH AN L01 AND NOT THE A31?
The story has a happy ending. Trusting in Aniwak's authority, the A31 ECU is working perfectly replacing a L01 based on my 240 mile test ride. I worked with my independent mechanic (Deftone Cycles, Chagrin Falls OH) to complete the diagnostics. After swapping positions of the knock sensors with no change in error code, replacing a sensor wiring harness that crumbled on removal, and testing and inspection of the wiring harness, I purchased and installed the A31. The bike is an 05, no ABS. Thank you ST-Owners.
Glad to hear your bike is repaired.
I have one question, when you said you replaced your sub wire harness because it crumbled when you removed it, did you happen to test ride the bike with your old ECU before you installed the new one?
I ask because I have found several bikes that have been repaired by replacing this harness instead of the ECU, and was just curious of which of these two things solved your problem.
I have one question, when you said you replaced your sub wire harness because it crumbled when you removed it, did you happen to test ride the bike with your old ECU before you installed the new one?
I ask because I have found several bikes that have been repaired by replacing this harness instead of the ECU, and was just curious of which of these two things solved your problem.
Very good question. The mechanic had me come to the shop after the sensors were swapped and the sub-harness replaced to see check if the codes changed. The same code occurred. When the ECU arrived I returned to the shop and confirmed the code was still occurring, then swapped the ECUs. Bike started on first try and the code no longer indicated even after running over 5000 rpm for over 30 seconds. Then a few days later took it out for the 240 mile run and pushed pretty hard.
OK, question for the Experts!
Since an '05 - '07 ECU will not work on a '04 (according from the info in this thread and I didn't miss understand) Would you be able to swap out the entire '04 harness with an '05 harness and the ECU, to have the '05 ECU work on your '04?
Just incase my '04 ECU goes belly up. Since I have a '05 ECU/Harness/parts bike.
Since an '05 - '07 ECU will not work on a '04 (according from the info in this thread and I didn't miss understand) Would you be able to swap out the entire '04 harness with an '05 harness and the ECU, to have the '05 ECU work on your '04?
Just incase my '04 ECU goes belly up. Since I have a '05 ECU/Harness/parts bike.
Interesting question. While not an ECU expert I am generally an expert in what we call today embedded systems. I run a small company that develops ECU type devices for hire. Think also of the controls or microprocessor in your printer or wireless router. The probability is nearly zero IMO that a harness change will work. We only go to the expense of changing wire harnesses if there is an additional sensor or actuator or some other signal needed to support a new feature (Common) or correct a critical problem (strongly avoid hardware changes). Normally there are new inputs or outputs that the existing bike doesn’t have, so the new changes to the harness don’t have anything to connect with on the old bike. One could imagine a scenario where this would not be the case, but in 40 years of product development I cannot recall one I have witnessed.
Trying to catch up on this thread.
Still not clear to me at this point: Does the 05 ECU fit the 04 harness or do they have different plug configurations?
Aniwak stated that the L01 ECU is the only one to work on the 03-04, and the L01 and A31 both worked on the 05. Therefore the connectors (plugs) for all L01 bikes and A31 bikes should be the same and that includes 03-05. I only have personal experience with the 05.
So 03 to 07 should have the same ECU plugs.
Plugs being the same, what are the differences between an 04 and an 05 harness?
If the part numbers are identical, yes. It is the exact same part. If not - I doubt it and I would not be the first to try it. Search the forums to see if anyone has gone there.
Okay, so the wire harnesses are the same: 32100-MCS-910 (just checked with Partzilla - which I should have done in the first place! 
Even, according to the part numbers, the ECU are the same: 38770-MCS-L01
So, I guess, I'm confused.
I guess, I'll pull the '05 ECU and test it on my '04. I might even try the '06 ST1300P and see if that works on the '04.
I'll let you know when I test them.
Even, according to the part numbers, the ECU are the same: 38770-MCS-L01
So, I guess, I'm confused.
I guess, I'll pull the '05 ECU and test it on my '04. I might even try the '06 ST1300P and see if that works on the '04.
I'll let you know when I test them.
For the sake of discussion, supposing this interchangeability works, is there a source of working ECUs?
03 and 04 have different Harness number...but same ECU. You never know.
I do not know. @Igofar stated specifically in this thread (see above) that the A31 will not work on the 03/04. only on the 05. My testimony is that it did work on my 05. I have no knowledge of the 03/04.
Okay, I have an '07. Where would I get a spare A31?