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That is crazy. It says the engine speed is abnormal but the fix is to check the ECU and MCU wiring.
So what exactly is it abnormal engine speed or a wiring issue making it think engine speed is abnormal.
Seems weird. What if the engine speed really was abnormal how is the wiring fixing that.
Interesting for sure.
 

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That is crazy. It says the engine speed is abnormal but the fix is to check the ECU and MCU wiring.
So what exactly is it abnormal engine speed or a wiring issue making it think engine speed is abnormal.
Seems weird. What if the engine speed really was abnormal how is the wiring fixing that.
Interesting for sure.
It would either indicate that the ECU or MCU is recieving an out of range signal for engine speed when compared to other sensor inputs. If the ECU or MCU has a bad connection or poor ground it could be that its not sinking an input to ground allowing for a false logic high input from the speed sensor.

With most ECU or MCU type units if the sensor inputs dont match it could very easily be a poor connection, water in a connector or a bad ground etc.

Keep in mind the fault occurs when the engine isnt running. so any engine speed input except 0 would be abnormal.

Just my guess.
Nate
 

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Get that but the trouble shooting never mentions checking any sensors or there outputs or if the engine speed actually is abnormal. Only thing is connections and wiring they mention. That I thought was a little weird.

It is denoting abnormal engine speed when the fix is not related to abnormal engine speed. It might as well denote screwed up wiring on ECU/MCU.

Most of which doesn't even make sense. Bent pins and all that only happen on assembly. If you haven't had it apart and it was working how would they get bent up inside a connector that is and has been plugged in since manufacture.

Not familiar with terminals up inside a connector magically getting bent by themselves when fully assembled. Interesting idea though.

Lots of trouble shooting in these manuals seems it is just copy and paste and of not much else. Generic suggestions for possible fixes at best

If it is electrical has a plug with terminals in it you wanna check those. Lol. Oh and if those are fine it must be you need new wiring altogether. I can just see someone following those suggestions and getting no where. Probably 10 different real reasons why it may occur outside of the connectors or the wiring don't you think.
 

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Keep in mind the least trained area for any mechanic is electronics and electrical troubleshooting. So the constant reminder to check connectors isnt too out of line. A lot of what is in a manual is to get the mechanic to look at the correct objects and usually in the correct order.

Lots of connectors end up being disconnected or manhandled during normal maintenance, damaged on reassembly and then fail out later down the road. I have repaired more cables and connectors that the operator swears they never touched or if they did went together just fine "....honest sarge, it was like that when I signed for it...."

Additionally vibration can damage connectors, connector bodies or wire-to-pin connections without any obvious external damage. A object dropped on a connector or pulled cable can also leave hidden damage. So pulling apart the connection and checking for missing or damaged pins should be step one, even if the last time it was connected was at the factory.
Nate
 

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My real point is if connectors look good there next step is new wiring harness.

How about a bad MCU like my friends with only 300 miles on it just experienced ? Or defective ECU ?

Check those after you have put in a new wiring harness seems out of order or left out completely is more like it.

Just seems odd to limit the fix to connectors or replace the wiring and that's it.

I do doubt very seriously if vibration does something to this style of connections it is going to be so ever slightly that your not going to pick up on it visually. Testing from the connector to the MCU or ECU is also impossible as you can't really test those connections when the waterproof multi wire connector is plugged into either you can no longer get to anything to test the connection if you wanted.

I just thought there should be some other examples of what the issue can be besides #1 check connectors than #2 replace the wiring harness.

I guess when MCU's go for $600 and sure the ECU is almost as much maybe that is the order of trial and error. Lol.

I guess lucky it's not the most common dreaded SH_37 code. Almost anything can be defective. MCU, ECU, Clutch actuator, Shift actuator and gear sensor to name a few.
 

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After a visual inspection of connectors you do a continuity check. Pin for pin of the harness. What you as the mechanic need to balance is the per hour cost of inspection versus the cost of replacement. If it cost less to replace than inspect, you replace.

I spent 22 years as a mechanic and ended up running maintenance operations for the US Army.

What the consumer frequently fails to realize is just how expensive man hours can be. When you repair or diagnose an issue you dont factor how long you spent doing it. If I'm billing you at $120.00 an hour it's cheaper for you to replace a $600 ECU than if I spend 4 hours ($480.00) to diagnose the $600 ECU. You just spent $1080 for the ECU.

Nate
 

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Unless it tests out fine then it would have saved you $120 on a part you didn't need.
But I get it. Easier to change the parts because it isn't really even possible to fully test it NOR it's connection to the wiring.

My friends 2019 with 300 miles on it is still in the shop 5 weeks now and no further along than when dropped off other than they now know a new MCU
did not fix it.
They are still trying parts. The $600 MCU didn't fix the issue. They are going to install a shift actuator next.
If Yamaha can't pick the right part then this could get really expensive trying to fix yourself. Not much different it doesn't seem as they are just swapping in parts until it works again. Lol. Good thing it is on their dime but a $28,000 machine sitting in the shop eating up driving and warranty time is still costing money.
 

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Unless it tests out fine then it would have saved you $120 on a part you didn't need.
But I get it. Easier to change the parts because it isn't really even possible to fully test it NOR it's connection to the wiring.

My friends 2019 with 300 miles on it is still in the shop 5 weeks now and no further along than when dropped off other than they now know a new MCU
did not fix it.
They are still trying parts. The $600 MCU didn't fix the issue. They are going to install a shift actuator next.
If Yamaha can't pick the right part then this could get really expensive trying to fix yourself. Not much different it doesn't seem as they are just swapping in parts until it works again. Lol. Good thing it is on their dime but a $28,000 machine sitting in the shop eating up driving and warranty time is still costing money.
One of the advantages we had was test equipment for every LRU and SRU.

That and what we called "shop spares". We kept a spare on hand for every electrical component. If something looked or seemed hinky, we would swap it for a shop spare before even going through diagnosis. If it fixed the problem, we just ordered a new shop spare and sent the vehicle out. If it didn't, then we could diagnose until we found the bad part and swap it out. Each replaced LRU went on the shelf as the new shop spare and the defective LRU was sent out for repair.

Believe it or not, the govt actually tries to be financially responsible. That and units actually pay for maintenance. So when an LRU can cost upwards of $100k, you only replace what's actually broke.

Seems like everytime I walk into a dealership I'm always surprised to find I'm dealing with either the JV or freshman team. Most haven't figured out why a good maintenance manager will get you gold on the sales floor. Probably the reason we have bought 5 vehicles from the same dealership, they understand maintenance.

For your friend, I hope they get their heads out of their 4th point of contact before the warranty times out.
Nate
 

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Heck of a way to fix things IMO. If there is no way to trouble shoot except to replace multiple $500 plus parts how the heck does a dealer or individual fix one if parts are on customers dime. It is on Yamaha's dime now and they are still not getting anywhere.
This is straight up bullshit. If a seasoned mechanic at the dealer has no way to test anything then Yamaha is just worthless for fixing these things if they can only swap out parts.
Who pays for all the parts they diagnose incorrectly when you are paying them $160 an hour to diagnose when they evidently can't diagnose nothing. What do you even need a mechanic for then. Anybody can pull parts and swap until it is fixed.

And it wouldn't be at 1 part to try every 5 weeks. It is under warranty and they are just screwing around instead of fixing the buggy.
Only plugging in a new MCU in 5 weeks would have me picking up my shit and taking it back to the dealer it came from. Their YES warranty isn't worth a rats ass when they are just letting the thing sit.
The reason I say that is because it came from a dealer near me and they are pretty good but his dealer 100 miles away I do not know but the stories he has told me I think he would be better at dealer near me where he bought it at.

Now they are closing up the dealer until middle of April. Not much you can do with everything closed but our trails are still open if you have yearly passes which we both have but missing a brand new buggy. He is bumming. I am bumming as bad with no body to ride with.

They need to fix it if it means parking a new one next to it and swapping parts until the sob works again. Seeing as they can not test or diagnose nothing on these things. They are definitely lacking in the training at the dealer or the design is just that bad with no real diagnostics possible to trouble shoot or testing equipment in the shops. It is buyer beware if a new machine could eat $5000 in parts and labor to fix a simple malfunction at only 300 miles.

In the scope of things right now it is a small thing. At least we are still alive.

EDIT,
Update 3-26
Shift actuator was installed and tested the machine and it is still doing the same thing. So two high dollar $500 plus each parts and we are still no better than 5 weeks ago except down some man hours and about $1200 in mis- diagnosed parts.

The bill so far and remember they are no further along than when it was brought in. $700 MCU $600 Shift actuator $2000 labor
$3300 for nothing. Imagine footing that ridiculous bill on a machine with only 300 miles on it and they can't fix it or haven't got anywhere with it yet I should say.
A system that even the dealers can not diagnose or troubleshoot or test components on is a real problem evidently.

EDIT 4-2
It is fixed. He got it back yesterday before statewide lockdown tonight at midnight.
Seems to be working properly on couple short test runs.
It was supposedly the shift actuator and something about the MCU not sending proper voltage to it.
 
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