Help / Ideas: Yamaha PWseries st - speed sensor issue ( resolved ).

[Slymobi]

Today I got a strange issue, no speed registered and motor cuts off after around 10-20 seconds riding. Absolutely NO error codes on display or in Self Diagnostic error check ( d3 ).
Full motor removal: I have checked all the cables and connectors which look fine, disconnected and reconnected each cable ( including the down tube display connector ) giving each a good inspection and air blow just in case multiple times ( up to 4 now ), checked alignment and cleaned sensor and magnet. Still the display will not register any speed which then cuts out the motor, if I power off and then on again I get a repeated scenario.
Left scratching my head as the display is fine and the motor still works until it's detecting no speed but no errors ?
Hoping it's nothing to do with the PCB board ? Ordered a new speed sensor at £25 as this is the lowest costing self check I can afford and don't really want to be throwing money at things that might not be the issue ! ( Display controller etc ).

Any ideas ?

Update: Resolved now

 

[Mikerb]

It may help if you mentioned what bike it is..and what specific motor since faults tend to occur in a similar way on any given bike.

Do you lose all power after 20 seconds...ie no lights on the display etc?. If you lose all power the fault is much more likely to be associated with battery connection. Im not sure the speed sensor has anything to do with it given the bike works for 20 seconds or so but the lack of any speed reading does suggest the information from the speed sensor is not getting to the controller.

 

[Slymobi]

It may help if you mentioned what bike it is..and what specific motor since faults tend to occur in a similar way on any given bike.

Do you lose all power after 20 seconds...ie no lights on the display etc?. If you lose all power the fault is much more likely to be associated with battery connection. Im not sure the speed sensor has anything to do with it given the bike works for 20 seconds or so but the lack of any speed reading does suggest the information from the speed sensor is not getting to the controller.

The bike is Haibike hardseven sduro 2.5 but didn't think that was relevant. The specific motor is in the title ( PWseriesST ).
I am familiar with the battery issue but this is different, the display does not cut out at point of issue and no errors, i only lose drive power.
When I say it works for around 20 seconds I'm referring to drive power but the speed is not registered at all. Hope that clarifies a bit better

 

[Mikerb]

OK. Can you think back what, if anything, you did to/with the bike since the previous time you used it when presumably it all worked as it should.

So any work you did on the bike, maintenance, any washing/cleaning, etc.

Have there been any previous problems with the bike?

Was the last ride a wet day?

Is the bike fitted with any derestriction devices?

does the controller have its own battery?

 

[Slymobi]

OK. Can you think back what, if anything, you did to/with the bike since the previous time you used it when presumably it all worked as it should.

So any work you did on the bike, maintenance, any washing/cleaning, etc.

Have there been any previous problems with the bike?

Was the last ride a wet day?

Is the bike fitted with any derestriction devices?

does the controller have its own battery?

So any work you did on the bike, maintenance, any washing/cleaning, etc.

Cleaned yesterday with low pressure hose as always and Fitted tannus inserts this morning.

Have there been any previous problems with the bike?

Only the common loose battery connection which has been resolved.

Was the last ride a wet day?

Extremely wet and muddy.

Is the bike fitted with any derestriction devices?

No, bought from new and happy with the limit as standard

does the controller have its own battery?

No it's wired.

@Mikerb it's like you said.... Just like nothing going from speed sensor to controller which results in the motor cutting off.

 

[Mikerb]

So 2 actions that may have caused the problem.
Fitting inserts means you removed the rear wheel so worth checking a gain that the speed sensor magnet and sensor have not been disturbed and are aligned. What is the arrangement for that? Disc rotor magnet ( bolt fixing rotor), direct mount rotor magnet, Wheel spoke magnet?
The other is washing the bike with a hose which could have flooded the controller. Might be worth removing the controller and leaving it in a warm place for a while.........or place it is a container with silicone crystals or rice.
Most water ingress to the electrical components on these bikes occurs with washing rather than when out on the trail regardless how wet the ride was.

 

[Slymobi]

So 2 actions that may have caused the problem.
Fitting inserts means you removed the rear wheel so worth checking a gain that the speed sensor magnet and sensor have not been disturbed and are aligned. What is the arrangement for that? Disc rotor magnet ( bolt fixing rotor), direct mount rotor magnet, Wheel spoke magnet?
The other is washing the bike with a hose which could have flooded the controller. Might be worth removing the controller and leaving it in a warm place for a while.........or place it is a container with silicone crystals or rice.
Most water ingress to the electrical components on these bikes occurs with washing rather than when out on the trail regardless how wet the ride was.

Sensor fitted to frame and magnet fitted onto spoke, I have checked and checked the sensor, magnet and alignment and it's all correct.
The water in the controller I could understand if any other issues were showing but all functions on the controller are working.
My fear is that the PCB has taken water and has damaged the sensor part ! The reason I think this is that where all the leads go into the motor housing it has a rubber seal / bung that on very close inspection had signs of water just underneath when lifted slightly.
It's still possible it's a broken speed sensor but absolute zero signs of damage to the connectors or cable in general so can only keep my fingers crossed that the new part fixes the issue because After liasing with the amazing @Bearing Man regarding this I've been informed that the PWST PCB is not available yet as the motor is still relatively new production.
Trying to get a warranty claim is most likely going to be impossible as I couldn't even get a failed front axle replaced by Haibike or the dealer I bought the bike from.
Seems like if you even change an inner tube without going through Haibike it voids your warranty lol.
The support I've received from both Haibike and bike shop is dreadful.

I appreciate the time and advice @Mikerb

 

[Slymobi]

I can't recreate the issue stationary as you have to be physically riding the motor for it to cut out but this image of the Speedo is with the wheel in motion at time of photo and as you can see it's showing zero mph when it should be showing some speed.

The magnet is aligned and the cable is good ( all the cable from sensor to connector in tube ).

 

[Mikerb]

getting a PCB wet does not necessarilly damage it but will of course cause short circuits, although PCBs are usually covered in a lacquer these days which should protect against that. Salt deposits left when the water dries can cause damage and repeated attempts to power up can ultimately lead to component failure on the PCB. So if you suspect water ingress onto the PCB your only option is to try to dry it out. Removing that rubber grommet and feeding some warm air into the motor via the hole may be enough to dry any water ingress...worth a try. I guess water ingress to the PCB is possible if the motor area where the cables feed in is subjected to water pressure or if that grommet is a poor fit or indeed perished. I would still try drying out the controller anyway as well. Without a circuit diagram it is impossible to determine what symptoms may arise from water ingress in there.
In general just like any processor driven system, these bikes are initiated with a power on switch which has a low voltage on standby. It complete a low voltage circuit in the CAN which sends out a "hello" data package to each element of the system required for the bike to function. Only if all elements respond correctly is high voltage then switched from the battery to the motor. Your testing has shown that the bike does indeed power on so that would suggest all elements required have responded ( typically sensors) and as a result battery high voltage is supplied to the motor. The system then shuts down after a few seconds which suggests one of the elements fails to continue working. Alongside that, there is no speed recording from the outset and neither is there any error report. All of that suggests it is not a single component failure but more probably a complex series of short circuits and that suggests water ingress somewhere.
Drying things out is your best bet I reckon.

 

[bazxa]

Can you move the magnet to see if the sensor pickup is out of range because of manufacturing tolerances in the sensor or add a magnet to increase field strength to test. Good luck great reply above

 

[Mikerb]

try moving that spoke magnet a little more to the right....I dont know what the alignment should be..........maybe that vertical line on the sensor but to me that looks like it might be the left hand edge of the magnet rather than the middle. The mark on the spoke to the right of the magnet suggest it used to be more to the right as well. Easy to test.

 

[Happydog]

Could the actual magnet in the bit that screws over the spoke have fallen out?

 

[Slymobi]

Mikerb - only the motor cuts out after a few seconds riding not the controller, the controller retains power at all times during issue, the failure is the speed sensor info as the motor is reading no movement so stops providing drive.



Mikerb and bazxa - I have moved the magnet numerous times to test position etc hence the marks on the spoke now. The line mark is the alignment that the magnet should be central with, my camera angle makes it look slightly out.
Also as suggested I did try adding a magnet to existing ( great minds ) to no avail.

Happy dog - The magnet is still very much intact .

 

[bazxa]

Is it possible to do continuity checks, terminal to board?
love to know the fix.

 

[Slymobi]

Is it possible to do continuity checks, terminal to board?
love to know the fix.

Above my skill level lol, I would definitely break or blow something. It's a possibility that I can get it sent to @Bearing Man for this testing ( already discussed with him ) after I've made sure that the new speed sensor is tested. I have one on order and should be here Sunday.

 

[Slymobi]

Judgement day !! Did it work ?

( Video removed )

Yes, new cable resolved it.

 

[bazxa]

And the judgement?

 

[Slymobi]

And the judgement?

The video says it all, think my reaction was mild to the relief I actually felt lol.

If you can't be arsed with YT - Replacement speed sensor resolved the issue

 

[Mikerb]

well done...great news!!

 

[Slymobi]

well done...great news!!

I feared the worst and got a lovely surprise when it worked, for just a split second my heart sank as it took a fraction of time to register the speed at first but then happy days.
Appreciate the help and advice offered by the few that bothered

 

[bazxa]

Great outcome

 

[Mikerb]

I feared the worst and got a lovely surprise when it worked, for just a split second my heart sank as it took a fraction of time to register the speed at first but then happy days.
Appreciate the help and advice offered by the few that bothered

There is some learning there as well which could be applicable to more bikes than just yours. The "start up" software sequence I referenced clearly has some weaknesses. To recap.........the controller needs to get an "alive" response from each element of the system required for operation of the bike before allowing the motor to be powered up. Since your bike would indeed power up initially, that start up sequence obvious got a response from those elements.........only to shut down power to the motor shortly afterwards. So that means the return signal from the speed sensor was indeed recieved but that did not signify that the sensor was actually operating...merely that it was connected!
Logically it therefore means there was no sensor cable damage or connectivity issue, and that it was the actual sensor that was faulty.

It all helps fault diagnosis in the future!!

 

[Slymobi]

There is some learning there as well which could be applicable to more bikes than just yours. The "start up" software sequence I referenced clearly has some weaknesses. To recap.........the controller needs to get an "alive" response from each element of the system required for operation of the bike before allowing the motor to be powered up. Since your bike would indeed power up initially, that start up sequence obvious got a response from those elements.........only to shut down power to the motor shortly afterwards. So that means the return signal from the speed sensor was indeed recieved but that did not signify that the sensor was actually operating...merely that it was connected!
Logically it therefore means there was no sensor cable damage or connectivity issue, and that it was the actual sensor that was faulty.

It all helps fault diagnosis in the future!!

Yeah that makes sense for it to be the actual sensor and not the cable but there is one big flaw in this...
In testing I disconnected the sensor and cabling from the motor and the results were the same.
So the controller isn't actually needing a response from the sensor at all to start but somewhere is needing some response to continue ( if that makes sense ).