SW900 LCD controller, no PAS

[nickl]

I need advice on a problem. No pedal assist but throttle works. We have a 36v. 1000w motor attached to a controller (recently replaced), pedal cadence sensor and a SW900 display.
I have been through all the P settings and everything looks fine there although max speed setting (P08) is 84 and when I get to P05 walk mode automatically kicks in. I have checked the PAS sensor and that seems ok. I have disconnected the throttle to see if it forces the controller to use pedal assist but get nothing. All of this occured before the new controller was fitted so I am thinking that the controller is not the issue. I am thinking it may be a faulty switch box and display?

 

[matthewslack]

I need advice on a problem. No pedal assist but throttle works. We have a 36v. 1000w motor attached to a controller (recently replaced), pedal cadence sensor and a SW900 display.
I have been through all the P settings and everything looks fine there although max speed setting (P08) is 84 and when I get to P05 walk mode automatically kicks in. I have checked the PAS sensor and that seems ok. I have disconnected the throttle to see if it forces the controller to use pedal assist but get nothing. All of this occured before the new controller was fitted so I am thinking that the controller is not the issue. I am thinking it may be a faulty switch box and display?

Going back a bit, (1) did it all work properly a while ago? (2) is the controller change just as an upgrade, or had the controller failed?

If yes and yes, I would go back to original controller to eliminate it from enquiries, fix the problem and then swap the controller.

You probably have already, but no harm in exercising every connector, just to be really sure of proper contact, and a close look at every bit of wiring. Then it's back to the PAS sensor, checking alignment, gap etc.. Try a new PAS sensor maybe.

 

[nickl]

Going back a bit, (1) did it all work properly a while ago? (2) is the controller change just as an upgrade, or had the controller failed?

If yes and yes, I would go back to original controller to eliminate it from enquiries, fix the problem and then swap the controller.

You probably have already, but no harm in exercising every connector, just to be really sure of proper contact, and a close look at every bit of wiring. Then it's back to the PAS sensor, checking alignment, gap etc.. Try a new PAS sensor maybe.

The assist mode has never worked from new. The controller was swapped to eliminate it from the fault. The PAS sensor has been replaced and is picking up readings, all connections have been checked. Still no assist mode.

 

[AGS]

Have you tried pedalling backwards to see if the pas kicks in reverse?

 

[nickl]

No, would that mean crossed wires on the pedal sensor to the controller?

 

[AGS]

Not crossed wires, but some controllers have a function where you can reverse the pas signal so you don’t have to physically move the sensor to the other side of the

 

[nickl]

The assist mode did not work with the old controller or the new one. The old one was factory set ( it is an E-bike, not a conversion) and the sensor has been replaced so I do not think that the issue is there. Also I am getting a speed reading on the display when the bike is on a stand. Thanks for the suggestion though.

 

[AGS]

Has the sensor been replaced with one that has the same number of magnets?

And are all of the pas P settings set correctly from the manual:

P9 - Zero start & Non-zero Start. 0 is Zero Start, 1 is Non-zero Start
P10 - Driving mode:
0 - is driven by PAS. Throttle is useless at this time.
1 - is driven by Throttle. PAS is useless at this time.
2 - is driven by PAS & Throttle. Throttle is useless at Zero Start status.
P11 - PAS sensitivity. Range: 1-24
P12 - PAS start strength. Range: 0-5
P13 - PAS magnet type. There are 3 types: 5, 8, and 12.

 

[nickl]

Has the sensor been replaced with one that has the same number of magnets?

And are all of the pas P settings set correctly from the manual:

P9 - Zero start & Non-zero Start. 0 is Zero Start, 1 is Non-zero Start
P10 - Driving mode:
0 - is driven by PAS. Throttle is useless at this time.
1 - is driven by Throttle. PAS is useless at this time.
2 - is driven by PAS & Throttle. Throttle is useless at Zero Start status.
P11 - PAS sensitivity. Range: 1-24
P12 - PAS start strength. Range: 0-5
P13 - PAS magnet type. There are 3 types: 5, 8, and 12.

The sensor has a pick up in it. It picks up the pulses the magnets on the crank produce and the adjustments are among the P settings on the display.
I have played with most of the P settings ( the ones which are factory set I left alone) and tried P05, P10 and P12 in alternative ways but to no avail.
There is not a problem with the throttle(P09) it works fine, just no pedal assist.
P 13 is correct as you can count the number of magnets on the crank axle disc (factory set).
I thought I would mention that no error codes are showing. Also when scrolling through the P codes it would sometimes activate the lighting system randomly.
Would a faulty switch box connected to the display cut out the PAS?

 

[AGS]

So have you tried back peddling yet to see if it kicks in?

 

[matthewslack]

The good news is that your motor works and it is unlikely that both controllers would have the same fault, so don't give up, this will be simple and fixable, just not yet easy to find!

There is no telling what might happen if there's a switchbox problem, I'd just open it up and check for any obvious issues.

The pedal backwards is a real thing: some PAS sensors only work in one direction and they have been known to be installed the wrong way round.

 

[nickl]

The good news is that your motor works and it is unlikely that both controllers would have the same fault, so don't give up, this will be simple and fixable, just not yet easy to find!

There is no telling what might happen if there's a switchbox problem, I'd just open it up and check for any obvious issues.

The pedal backwards is a real thing: some PAS sensors only work in one direction and they have been known to be installed the wrong way round.

thanks for that,
I will try it and come back.

 

[AGS]

There are plenty of you tube videos of pas sensor problems and how to fix them. Some are cringeworthy and others are quite helpful. And remember not to make the common mistake of setting the bike at pas 0 when you are testing.

 

[nickl]

Have you tried pedalling backwards to see if the pas kicks in reverse?

I have just tried that and it doesn't work, but thanks anyway.

 

[nickl]

thanks for that,
I will try it and come back.

I have tried it, the sensor doesn't work when peddling backwards

 

[AGS]

In that case you will have to do some standard fault finding using a multimeter. Pas sensors usually have 3 wires, 5v, 0v and signal. When you pedal the signal wire will give a 5v pulse every time a magnet passes the sensor. And of course the 3 wires from the pedal sensor have to be connected to the correct 3 wires on the controller. The wiring colours can give an indication of which ones to connect. But in many cases the wires from the sensor are different colours to those on the controller. It is possible that the wiring combination is all mixed up, but that would be unusual for a manufactured bike. Most people who have problems mix them up when installing a mixture of parts bought from different suppliers.

 

[AGS]

May be a good time to post a photograph of the connector from the sensor to the controller, which will hopefully show the wiring colours.

 

[Dave Mcg Clarke]

Did you get this sorted?

 

[saneagle]

Did you get this sorted?

If you have a problem, start a new thread and tell us what it is. Please describe exactly what parts you have and any history. The OP in this one never expl;ained what he'd done other than replaced a controller.