Helping a friend with a Gen 2: FI light C41/C42 no start but cranks over!

[Slowstang305]

Hey guys,

trying to help a friend with his Gen 2. Its a newer one either a 2018/19/20 model Gen 2, not sure off the top of my head.

He was riding on the highway when the bike lost all power. He pulled over to the side of the road and try to start the bike but it was dead in the water, gauges flashing etc. I brought him a good working battery to put into his bike from my bike. Once we put the battery in the bike now cranks and cranks but will not fire. He does not hear the fuel pump priming. FI light came on and jumping the connections it came up with C41/C42.

He has already checked the tip over sensor that we read was an issue on the Gen 1's with the brackets breaking. Different set up altogether on Gen 2 it seems. He checked the 10amp fuel pump fuse and it was good. Threw another one in there just in case and that did not resolve the issue. Checked the wiring on the fuel pump and everything seems tight and in place.

Any other ideas you guys may have. Our next thought is ECU related.....

SUMMARY: Gen 2 lost all power on highway. Battery shot. Replaced with new battery bike cranks over but will not fire. Fuel pump does not prime. Code C41/C42.

 

[HayaWakened]

C42 applies only to Euro Busa?
C41 Fuel Pump relay

 

[Kiwi Rider]

Check for 12v going to the fuel pump at the pump connector.
If there is 12v going to the pump it’s gonna be a dead fuel pump, fit a new pump.
If there’s not 12v at the pump connector, start testing with a meter going back through the circuit to the relay, testing for power output, using a circuit diagram.
Get a manual and start testing.
Also, you’ll need to test the stator and voltage regulator, that may be faulty (shorted) or a melted connector plug from the stator to the regulator and be the reason why the battery drained down causing bike to die on the highway while riding.
Let us know the outcome.

 

[Bumblebee]

Are there any programmers on the bike?

My Bazzaz caused the same issue as this last summer....

Before hand I replaced all the fuses and the fuel pump relay located on the left hand side beside the rear seat by taking off the tail section to no avail....

 

[Slowstang305]

Thank you to all for the replies, @Bumblebee @Kiwi Rider @HayaWakened !!!

We tried everything possible and could not get the fuel pump to prime. Turns out the problem was the ECU. We swapped in a working gen 2 ECU and the pump primed and the bike came to life.

If I had to guess... the old battery had some sort of short and caused the electronics to go haywire blowing out the ECU.

Thanks to all and hopefully whoever finds this thread in the future finds it helpful.

 

[toncrell]

This maybe a long shot but just yesterday I had the same problem on my Ktm rc8 and got a ton of codes flashing and then dash and lights stopped totally when I got bike home I looked at my battery and all cables were tight but as I wiggled the actual post it came out of the battery with cabels and all so I had to get a new battery. If your friends battery is not new this could be the cause. Tech at shop told me old battery can have this problem. Hope this helps

 

[Slowstang305]

This maybe a long shot but just yesterday I had the same problem on my Ktm rc8 and got a ton of codes flashing and then dash and lights stopped totally when I got bike home I looked at my battery and all cables were tight but as I wiggled the actual post it came out of the battery with cabels and all so I had to get a new battery. If your friends battery is not new this could be the cause. Tech at shop told me old battery can have this problem. Hope this helps

Thank you my friend. We did test with a brand new battery and even a good working battery first and same issue. Ended up being the ECU had fried....

 

[Kiwi Rider]

Thank you to all for the replies, @Bumblebee @Kiwi Rider @HayaWakened !!!

We tried everything possible and could not get the fuel pump to prime. Turns out the problem was the ECU. We swapped in a working gen 2 ECU and the pump primed and the bike came to life.

If I had to guess... the old battery had some sort of short and caused the electronics to go haywire blowing out the ECU.

Thanks to all and hopefully whoever finds this thread in the future finds it helpful.

Wow!
Very very unusual to hear of an ECU fault like that.
Have you checked the charge rate?
If the voltage regulator is bad and output voltage is high as in 15v or even much higher, that could cause a voltage spike/overload to the ECU…. Maybe?
I’ve never heard of or seen such a fault occurring.
Glad you’ve found the cause and relatively easy to sort it.
Have you found an ECU for the bike?

 

[sixpack577]

Wow!
Very very unusual to hear of an ECU fault like that.
Have you checked the charge rate?
If the voltage regulator is bad and output voltage is high as in 15v or even much higher, that could cause a voltage spike/overload to the ECU…. Maybe?
I’ve never heard of or seen such a fault occurring.
Glad you’ve found the cause and relatively easy to sort it.
Have you found an ECU for the bike?

+1
Regardless of fuses and relays, I have seen at least 3 regulator/rectifiers fail over the years...and they can cause some really strange electrical gremlins, and ones that you never find...until the reg/rec completely gives out, vs a hit and miss problem.
My friend was lucky his Buell finally shut off last summer, It had been doing crazy things too, and charging fine.
When I got there with the truck, the battery had swolen badly, it was sizzling, and you could feel the heat, it was really hard to get it out of the bike...I would not like to have that thing explode directly under the driver's seat either...
So yes, absoloutely, check the charging on that bike, and if it's good, check the reg/rec the next day, and a few days after.
Better safe than sorry.

 

[sixpack577]

Also
There is no real way to test a regulator/rectifier, so when I say to check it, I mean to test the battery again, and again the next day, and so on.
Make sure the bike isn't under or over charging it at any time.
As I have seen reg/recs work fine, then the gremlins show up, they disapear before testing the battery, and all seems well...until the next time.
They can be hit and miss and hard to catch failing sometimes.

 

[Kiwi Rider]

Also
There is no real way to test a regulator/rectifier, so when I say to check it, I mean to test the battery again, and again the next day, and so on.
Make sure the bike isn't under or over charging it at any time.
As I have seen reg/recs work fine, then the gremlins show up, they disapear before testing the battery, and all seems well...until the next time.
They can be hit and miss and hard to catch failing sometimes.

Yes, reg/rec's are a pain to test.
The Suzuki manual shows a diagram for testing with all the resistance values on a graph . . but they say you must use a Suzuki "pocket tester" to get accurate readings when testing it. I've tried using a regular quality multi-meter but the values I get are never anywhere near the book values. And that is with testing a brand new one!
I've never seen one of those pocket testers, so really the only way I've tested reg/recs is to look at the output voltage at the battery while the bike is running . . . if the battery voltage is way high, it will be a regulator fault, if the battery voltage is too low check the stator voltage output (AC voltage) at all 3 phases, if its ok then replace the regulator.
Job done.

 

[Kiwi Rider]

+1
Regardless of fuses and relays, I have seen at least 3 regulator/rectifiers fail over the years...and they can cause some really strange electrical gremlins, and ones that you never find...until the reg/rec completely gives out, vs a hit and miss problem.
My friend was lucky his Buell finally shut off last summer, It had been doing crazy things too, and charging fine.
When I got there with the truck, the battery had swolen badly, it was sizzling, and you could feel the heat, it was really hard to get it out of the bike...I would not like to have that thing explode directly under the driver's seat either...
So yes, absoloutely, check the charging on that bike, and if it's good, check the reg/rec the next day, and a few days after.
Better safe than sorry.

I like the way you think man!
I always enjoy reading your input.
I've also repaired an early Buell with the same issues, I think it may be a genetic issue with the Buell family lol.

 

[sixpack577]

I like the way you think man!
I always enjoy reading your input.
I've also repaired an early Buell with the same issues, I think it may be a genetic issue with the Buell family lol.

Right on man,
Same here...I even had an old kiwi help me with a couple bikes before...
lol

 

[Slowstang305]

Thank you both for all the replies! This forum is a wealth of knowledge! We are still in search of an ECU. All wiring looks intact and battery voltage seems to be right with the ECU out of my bike that was in there for a bit. Will keep this thread updated and let you guys know what happens with his bike.

 

[toncrell]

Glad ya found the problem