Fault Code No. 12

[The Chicken Man]

Fault code No. 12

According to page 8-4 of the service manual:
Item: Crankshaft position sensor: no normal signals are received from the crankshaft position sensor.
Fail-safe System: Unable to start engine, Unable to drive vehicle
Reinstatement method: Cranking the engine.

Has anyone here encountered this fault code before? And if so, what symptoms did you experience? How did you fix your issue?

I've read other people mentioning this code in comments on other threads, some stating they replaced their stator & sensor assembly. But I'd like to start a dedicated thread to this issue to leave some info behind for future readers.

My experience:

My bike is a 2009. I've owned my bike for about 3 months and 700 miles now. Sunday, 7/30/2023 I drove my bike across to town to a friend's shop to help them work on their truck. Went to go leave and encountered this issue. The bike would power up normally when I turned the key on, but when I would press the start button it would not crank. A clicking sound could be heard each time I pressed the start button (I assume the starter relay) but the bike would not attempt to crank. Additionally, every time I would press the start button the engine light and abs light would illuminate for as long as I held the button but would turn off when I let off the button. However, if I held the start button for several second the engine light would start to blink, then once I would release the button the engine light would stay on. Once the engine light was on, the diagnostic mode would show a single code, code 12. I could clear this code and replicate this process. I was stranded.

I spent the afternoon, tearing into the bike. I knew the code was for the Crankshaft Position Sensor, but I didn't have my service manual to check where it was located. So, I returned today with information in hand. The service manual gives instructions on how to check this sensor in section "Checking the Crankshaft Position Sensor" (page 8-132), which basically consists of unplugging the connector to check for continuity and measure resistance across the two wires (192–288 Ω at 20°C/68°F). Pages 2-55 and 5-4 indicate that the connector for the crankshaft position sensor is located behind the engine on the left side of the bike. I found mine sandwiched between the fuel tank and the heatshield behind the engine. See the below photos.



Has anyone tested their sensor before? My issue is that this connector's location makes it nearly inaccessible. The heatshield does not appear to be removable from the front so my only thought is that the fuel tank must be removed to access it. That seems like a lot of work for something that needs to tested for diagnosis. I'm curious how others may have done this.

Luckly for me, my issues went away as suddenly as it appeared. When I saw how hard it would be to access the plug I decided to see if maybe my bike might just start, and it did! I cleared the existing code and it has not come back yet. It's possible I inadvertently fixed my issue while doing all the digging around in my bike that I did, but I'm skeptical of that. I know this could just be a fluke, but my concern is that this issue could come back again. I fear this could become an intermittent issue and that it may leave me stranded somewhere far from home.

The fail-safe condition the service manual mentions implies to me that a no crank condition is normal/is what should occur when this fault is detected. But I do not have any confirmation of what caused the fault. Perhaps this is the early signs of the crankshaft position sensor going out? Do you think it is type of component is one to fail slowly/intermittently or would it more likely just quit all at once? Or maybe this issue is being caused by something else entirely. What are y'alls thoughts?

NOTE: I have not experienced this issue or any like it before. I also saw no corrosion or damage to any wire or connectors (at least those that I could see).

It's a pretty expensive part and the wiring seems like it will make it a tough one to replace, so I don't know if I can justify replacing it just for the sake of calming my nerves. I have a new larger fuel tank that will be installing eventually, so if I can verify that there is an issue with the sensor first that would be a convenient time to replace it.


https://www.partzilla.com/catalog/yamaha/motorcycle/2009/v-max-vmx17yb/generator

 

[MaxMidnight]

Whilst I don't know the answer to your problem the first thing I would always suggest when suspecting a continuity issue is to make and break the connector several times.
That is sufficient to clean up the contacts and restore continuity.
It may well be that by moving the wiring about this is what you managed to achieve?

 

[mymax]

Fault code No. 12

According to page 8-4 of the service manual:
Item: Crankshaft position sensor: no normal signals are received from the crankshaft position sensor.
Fail-safe System: Unable to start engine, Unable to drive vehicle
Reinstatement method: Cranking the engine.

Has anyone here encountered this fault code before? And if so, what symptoms did you experience? How did you fix your issue?

I've read other people mentioning this code in comments on other threads, some stating they replaced their stator & sensor assembly. But I'd like to start a dedicated thread to this issue to leave some info behind for future readers.

My experience:

My bike is a 2009. I've owned my bike for about 3 months and 700 miles now. Sunday, 7/30/2023 I drove my bike across to town to a friend's shop to help them work on their truck. Went to go leave and encountered this issue. The bike would power up normally when I turned the key on, but when I would press the start button it would not crank. A clicking sound could be heard each time I pressed the start button (I assume the starter relay) but the bike would not attempt to crank. Additionally, every time I would press the start button the engine light and abs light would illuminate for as long as I held the button but would turn off when I let off the button. However, if I held the start button for several second the engine light would start to blink, then once I would release the button the engine light would stay on. Once the engine light was on, the diagnostic mode would show a single code, code 12. I could clear this code and replicate this process. I was stranded.

I spent the afternoon, tearing into the bike. I knew the code was for the Crankshaft Position Sensor, but I didn't have my service manual to check where it was located. So, I returned today with information in hand. The service manual gives instructions on how to check this sensor in section "Checking the Crankshaft Position Sensor" (page 8-132), which basically consists of unplugging the connector to check for continuity and measure resistance across the two wires (192–288 Ω at 20°C/68°F). Pages 2-55 and 5-4 indicate that the connector for the crankshaft position sensor is located behind the engine on the left side of the bike. I found mine sandwiched between the fuel tank and the heatshield behind the engine. See the below photos.

View attachment 90372View attachment 90373View attachment 90374View attachment 90375

Has anyone tested their sensor before? My issue is that this connector's location makes it nearly inaccessible. The heatshield does not appear to be removable from the front so my only thought is that the fuel tank must be removed to access it. That seems like a lot of work for something that needs to tested for diagnosis. I'm curious how others may have done this.

Luckly for me, my issues went away as suddenly as it appeared. When I saw how hard it would be to access the plug I decided to see if maybe my bike might just start, and it did! I cleared the existing code and it has not come back yet. It's possible I inadvertently fixed my issue while doing all the digging around in my bike that I did, but I'm skeptical of that. I know this could just be a fluke, but my concern is that this issue could come back again. I fear this could become an intermittent issue and that it may leave me stranded somewhere far from home.

The fail-safe condition the service manual mentions implies to me that a no crank condition is normal/is what should occur when this fault is detected. But I do not have any confirmation of what caused the fault. Perhaps this is the early signs of the crankshaft position sensor going out? Do you think it is type of component is one to fail slowly/intermittently or would it more likely just quit all at once? Or maybe this issue is being caused by something else entirely. What are y'alls thoughts?

NOTE: I have not experienced this issue or any like it before. I also saw no corrosion or damage to any wire or connectors (at least those that I could see).

It's a pretty expensive part and the wiring seems like it will make it a tough one to replace, so I don't know if I can justify replacing it just for the sake of calming my nerves. I have a new larger fuel tank that will be installing eventually, so if I can verify that there is an issue with the sensor first that would be a convenient time to replace it.

View attachment 90376
https://www.partzilla.com/catalog/yamaha/motorcycle/2009/v-max-vmx17yb/generator

Hi
I have 2019 max and encounter the same exact isssue at 9000 miles the bike will start but will stop and I have to push start and code 12 with engine lights will come on I took it to dealership and they change the battery first which did not help and then they check all electrical and change stator coil and change aftermarket head lamp bulb and I have almost 15000 miles now and bike is perfect see if Yamaha can cover this issue under warranty
Gorki

 

[g2gboom]

That looks like the wiring/harness for the sensor but what about the sensor itself. Shouldnt that be located near the bottom of the crankcase close to the crankshaft itself? I suspect that that would be more likely. My suspicion is that water build up or accumulation occured at the sensor location which is resulting in intermitent resistance / false readings resulting in a no start.

 

[The Chicken Man]

I have an update for all those following and future readers.

Thank you to all who responded!

TL;DR: The source of my problem was my starter. It was dirty inside and cleaning it resolved my issue.

Following this post, I rode my bike several more times intermittently experiencing the same issues. Sometimes it would start and sometimes it would not crank. I found that when it would not crank, I could put it in gear, let the clutch out, rock the bike back and forth a little bit, then try starting it again and after that it would usually crank. Pop starting also work. But one thing that was consistent was that when it would crank it was always very slow and would get slower with each revolution (I should have taken a video of this to share). Symptomatically it sounded like a low battery.

So, I load tested my battery figuring, whether it was the issue or not, I should replace it if it was bad. It had no date sticker so I could not determine how old it was, but it read a little less than 200CCA on the load tester. Probably not low enough to cause the extremely slow cranking I was experiencing but the battery was rated at 230CCA, so I opted to replace it. I went with a NOCO NLP14 lithium battery for my new one. It's supposed to provide "500A of starting power" which I assume means 500CCA, this should help improve cranking power. I also picked up NOCO's Genius 1 charger. All this costing $164.45 in total after tax and all. Nevertheless, after charging and installing the battery I was still experiencing the same intermittent not crank issue and it was still cranking just as slow. This to me showed that this was more likely a connection (something creating a lot of resistance) and I started to suspect the starter motor.

Links to battery and charger for reference:
- NOCO - 500A Lithium Powersport Battery - NLP14
- NOCO - 1-Amp Smart Battery Charger - GENIUS1

So, I pulled the starter, and the exhaust to gain access to it, and inspected it following the procedure in the service manual (section: "ELECTRIC STARTER" pages 5-44 thru 5-47). All the measurements and multimeter readings checked out fine, but I also found was a considerable amount of dust from the brushes inside. I forgot to take many photos, but this picture of the front cover shows what I found. There was dust like this all throughout the starter.


Starter front cover with brush set installed.

The dust was packed in between the brushes and their guides, adding resistance to their movement. After cleaning it them out they had noticeably better spring pressure and protruded out a bit more than in the picture above. But I think bigger issue I had was on the armature assembly. On the commutator surface there was a solid layer of brush dust packed on, thick enough to feel with my fingernail. I sadly forgot to take a picture of this, but the picture below shows the armature after I cleaned it. You can tell where I cleaned it because its extra shinny. That whole shinny area was black prior.


Armature assembly: circled area is the commutator.

The service manual even gives specific instructions on how to the commutator surface on page (5-45). I simply followed these instructions for cleaning and inspecting.


Image from page 5-45 of the service manual referring to the commutator.

After cleaning everything and putting it all back together my bike is cranking faster than it ever has since I've owned it. It also has not failed to crank since. Seems that the dust build up around the brushes and on the commutator was creating enough resistance to slow and even stop my starter from spinning.

Fault code No. 12

My thoughts on why I was getting this code. As previously stated, this code would only appear if I held the start button for several seconds. My theory on this is that the crankshaft position sensor must be the ECM's primary way to know if the motor is spinning. So, when I was holding the start button, but the engine was failing to crank, the ECM was assuming the engine was turning and waiting to see a reading from the crankshaft position sensor. But when it didn't after several seconds (because the engine was not cranking) the ECM would simply assume that there was an issue with the sensor and throw that code.

If this theory is true, it means that other issues that would stop the motor from cranking/turning could also cause this fault code (stater relay, starter wiring, loose connection, physical/mechanical motor problems, etc.) Many things could cause the bike to throw a fault code no. 12 that are not the sensor itself. So, if you see this code don't instantly freak out and think you need a new stator like I did.

The last take away from my experience here that this is another example that the starter motor itself is a possible source of slow/no crank issues. And that when the starters do fail, they do not always need to be replaced. Which is good because new OEM one is over $500 on Partzilla right now.

https://www.partzilla.com/catalog/yamaha/motorcycle/2009/v-max-vmx17yb/starting-motor

 

[MaxMidnight]

Excellent write-up, thank you for sharing.

 

[Bullseye092]

I have an update for all those following and future readers.

Thank you to all who responded!

TL;DR: The source of my problem was my starter. It was dirty inside and cleaning it resolved my issue.

Following this post, I rode my bike several more times intermittently experiencing the same issues. Sometimes it would start and sometimes it would not crank. I found that when it would not crank, I could put it in gear, let the clutch out, rock the bike back and forth a little bit, then try starting it again and after that it would usually crank. Pop starting also work. But one thing that was consistent was that when it would crank it was always very slow and would get slower with each revolution (I should have taken a video of this to share). Symptomatically it sounded like a low battery.

So, I load tested my battery figuring, whether it was the issue or not, I should replace it if it was bad. It had no date sticker so I could not determine how old it was, but it read a little less than 200CCA on the load tester. Probably not low enough to cause the extremely slow cranking I was experiencing but the battery was rated at 230CCA, so I opted to replace it. I went with a NOCO NLP14 lithium battery for my new one. It's supposed to provide "500A of starting power" which I assume means 500CCA, this should help improve cranking power. I also picked up NOCO's Genius 1 charger. All this costing $164.45 in total after tax and all. Nevertheless, after charging and installing the battery I was still experiencing the same intermittent not crank issue and it was still cranking just as slow. This to me showed that this was more likely a connection (something creating a lot of resistance) and I started to suspect the starter motor.

Links to battery and charger for reference:
- NOCO - 500A Lithium Powersport Battery - NLP14
- NOCO - 1-Amp Smart Battery Charger - GENIUS1

So, I pulled the starter, and the exhaust to gain access to it, and inspected it following the procedure in the service manual (section: "ELECTRIC STARTER" pages 5-44 thru 5-47). All the measurements and multimeter readings checked out fine, but I also found was a considerable amount of dust from the brushes inside. I forgot to take many photos, but this picture of the front cover shows what I found. There was dust like this all throughout the starter.

View attachment 90618
Starter front cover with brush set installed.

The dust was packed in between the brushes and their guides, adding resistance to their movement. After cleaning it them out they had noticeably better spring pressure and protruded out a bit more than in the picture above. But I think bigger issue I had was on the armature assembly. On the commutator surface there was a solid layer of brush dust packed on, thick enough to feel with my fingernail. I sadly forgot to take a picture of this, but the picture below shows the armature after I cleaned it. You can tell where I cleaned it because its extra shinny. That whole shinny area was black prior.

View attachment 90619
Armature assembly: circled area is the commutator.

The service manual even gives specific instructions on how to the commutator surface on page (5-45). I simply followed these instructions for cleaning and inspecting.

View attachment 90620
Image from page 5-45 of the service manual referring to the commutator.

After cleaning everything and putting it all back together my bike is cranking faster than it ever has since I've owned it. It also has not failed to crank since. Seems that the dust build up around the brushes and on the commutator was creating enough resistance to slow and even stop my starter from spinning.

Fault code No. 12

My thoughts on why I was getting this code. As previously stated, this code would only appear if I held the start button for several seconds. My theory on this is that the crankshaft position sensor must be the ECM's primary way to know if the motor is spinning. So, when I was holding the start button, but the engine was failing to crank, the ECM was assuming the engine was turning and waiting to see a reading from the crankshaft position sensor. But when it didn't after several seconds (because the engine was not cranking) the ECM would simply assume that there was an issue with the sensor and throw that code.

If this theory is true, it means that other issues that would stop the motor from cranking/turning could also cause this fault code (stater relay, starter wiring, loose connection, physical/mechanical motor problems, etc.) Many things could cause the bike to throw a fault code no. 12 that are not the sensor itself. So, if you see this code don't instantly freak out and think you need a new stator like I did.

The last take away from my experience here that this is another example that the starter motor itself is a possible source of slow/no crank issues. And that when the starters do fail, they do not always need to be replaced. Which is good because new OEM one is over $500 on Partzilla right now.

https://www.partzilla.com/catalog/yamaha/motorcycle/2009/v-max-vmx17yb/starting-motor

Followed this advice 2 days ago when your issues sounded eerily similar. So far haven't taken it back out yet, but it has started successfully with no hesitation in the garage a dozen times now. Think you were a lifesaver!

 

[The Chicken Man]

Followed this advice 2 days ago when your issues sounded eerily similar. So far haven't taken it back out yet, but it has started successfully with no hesitation in the garage a dozen times now. Think you were a lifesaver!

Glad to hear that the information is making a difference! My bike is still starting perfectly and hasn't shown any signs of issue since the repair. Hope your issue is resolved too!

 

[mymax]

Fault code No. 12

According to page 8-4 of the service manual:
Item: Crankshaft position sensor: no normal signals are received from the crankshaft position sensor.
Fail-safe System: Unable to start engine, Unable to drive vehicle
Reinstatement method: Cranking the engine.

Has anyone here encountered this fault code before? And if so, what symptoms did you experience? How did you fix your issue?

I've read other people mentioning this code in comments on other threads, some stating they replaced their stator & sensor assembly. But I'd like to start a dedicated thread to this issue to leave some info behind for future readers.

My experience:

My bike is a 2009. I've owned my bike for about 3 months and 700 miles now. Sunday, 7/30/2023 I drove my bike across to town to a friend's shop to help them work on their truck. Went to go leave and encountered this issue. The bike would power up normally when I turned the key on, but when I would press the start button it would not crank. A clicking sound could be heard each time I pressed the start button (I assume the starter relay) but the bike would not attempt to crank. Additionally, every time I would press the start button the engine light and abs light would illuminate for as long as I held the button but would turn off when I let off the button. However, if I held the start button for several second the engine light would start to blink, then once I would release the button the engine light would stay on. Once the engine light was on, the diagnostic mode would show a single code, code 12. I could clear this code and replicate this process. I was stranded.

I spent the afternoon, tearing into the bike. I knew the code was for the Crankshaft Position Sensor, but I didn't have my service manual to check where it was located. So, I returned today with information in hand. The service manual gives instructions on how to check this sensor in section "Checking the Crankshaft Position Sensor" (page 8-132), which basically consists of unplugging the connector to check for continuity and measure resistance across the two wires (192–288 Ω at 20°C/68°F). Pages 2-55 and 5-4 indicate that the connector for the crankshaft position sensor is located behind the engine on the left side of the bike. I found mine sandwiched between the fuel tank and the heatshield behind the engine. See the below photos.

View attachment 90372View attachment 90373View attachment 90374View attachment 90375

Has anyone tested their sensor before? My issue is that this connector's location makes it nearly inaccessible. The heatshield does not appear to be removable from the front so my only thought is that the fuel tank must be removed to access it. That seems like a lot of work for something that needs to tested for diagnosis. I'm curious how others may have done this.

Luckly for me, my issues went away as suddenly as it appeared. When I saw how hard it would be to access the plug I decided to see if maybe my bike might just start, and it did! I cleared the existing code and it has not come back yet. It's possible I inadvertently fixed my issue while doing all the digging around in my bike that I did, but I'm skeptical of that. I know this could just be a fluke, but my concern is that this issue could come back again. I fear this could become an intermittent issue and that it may leave me stranded somewhere far from home.

The fail-safe condition the service manual mentions implies to me that a no crank condition is normal/is what should occur when this fault is detected. But I do not have any confirmation of what caused the fault. Perhaps this is the early signs of the crankshaft position sensor going out? Do you think it is type of component is one to fail slowly/intermittently or would it more likely just quit all at once? Or maybe this issue is being caused by something else entirely. What are y'alls thoughts?

NOTE: I have not experienced this issue or any like it before. I also saw no corrosion or damage to any wire or connectors (at least those that I could see).

It's a pretty expensive part and the wiring seems like it will make it a tough one to replace, so I don't know if I can justify replacing it just for the sake of calming my nerves. I have a new larger fuel tank that will be installing eventually, so if I can verify that there is an issue with the sensor first that would be a convenient time to replace it.

View attachment 90376
https://www.partzilla.com/catalog/yamaha/motorcycle/2009/v-max-vmx17yb/generator

Yes my gen 2 had code 12 at 10 k won’t start and once I push start but will stall so dealer changed the battery first and did not help and finally changed the stator assembly and have no issue since

 

[Jaketheone46]

Glad to hear that the information is making a difference! My bike is still starting perfectly and hasn't shown any signs of issue since the repair. Hope your issue is resolved too!

Always awesome to see a thread with the solution added. I’ll never understand why people never come back to add the solution but it makes me not want to assist them whatsoever when they pop up with their next issue. How many miles was on your bike when this happened??
I have a 09 with 10k on it and it always starts fine but does seem to turn over slow when comparing to my other motorcycles. It could be totally normal though.

 

[Bullseye092]

Glad to hear that the information is making a difference! My bike is still starting perfectly and hasn't shown any signs of issue since the repair. Hope your issue is resolved too!

Glad to hear that the information is making a difference! My bike is still starting perfectly and hasn't shown any signs of issue since the repair. Hope your issue is resolved too!

Almost 6 months and not one issue since. Polished that core up like a new penny and she's cranked perfectly ever since!

 

[The Chicken Man]

Always awesome to see a thread with the solution added. I’ll never understand why people never come back to add the solution but it makes me not want to assist them whatsoever when they pop up with their next issue. How many miles was on your bike when this happened??
I have a 09 with 10k on it and it always starts fine but does seem to turn over slow when comparing to my other motorcycles. It could be totally normal though.

I feel you. I always like to come back and update posts with solutions if I find them. I hope all this info will continue to help people in the future.

My bike had a little over 21k miles when I first started experiencing the issue. I bought my bike used with about 20k miles on it not long before I started having this issue, so I don't know the whole history of my bike. But I did notice a few marks on the starter where it looked like someone had been tapping on it. So, it's possible my bike may have had starting issues before.

My understanding is that these bikes do crank slower than most bikes, even when everything is working properly. I feel like they probably could have used a bigger starter motor considering the size of these engines, but I suppose that's probably why they felt the need to add a decompression system. Regardless, if your 2nd gen cranks a little slow that's likely totally fine and normal, I would only start to get concerned if you notice it slowing down as it cranks.