Help! PAS Not Working Now - Help Please!

[chris301up]

I have been in the process of restoring my old electric bike and finally got around to the rewiring the electrics. Unfortunately, it doesn't look like the PAS working. Other than removing the sensor from the bottom bracket when replacing the bearings I haven't done anything to it. Is there any way this can be tested? I will say that should I connect a multimeter to the red & black wires I get a reading of 4.32 volts, and when I connect to the green & black wires (which I understand is the signal wires) I get a constant reading of 1.33 volts, which doesn't fluctuate when turning the crank. I have attached pictures showing my readings.

Just for piece of mind I have turned the magnetic disc on the crank and this doesn't affect the readings in any way. Am I doing something wrong or is it stuffed?

 

[vfr400]

Try swapping the blue and yellow wires.

 

[chris301up]

They will only fit one way due to the plug and socket orientation. This is wired exactly the same from when I disconnected it previously. I can of course remove and replace the inline connectors and give that a go.

 

[vfr400]

That won't be it then. Sometimes Chinese use Yellow as ground and sometimes blue - the same with the signal wires. If it worked before, the colours must be right. Can we see a photo of the pedal sensor?

 

[Nealh]

Is the sensor orientated the correct way and is the gap between disc and sensor about 1 or 2mm.

 

[chris301up]

Is the sensor orientated the correct way and is the gap between disc and sensor about 1 or 2mm.

Yes. The sensor can only go one way and the gap is the same as previously installed. The magnetic disc is almost, but not quite touching the sensor. Haven't measured it in MM though. As mentioned in my post I have tried it in both directions, but nothing.

 

[chris301up]

That won't be it then. Sometimes Chinese use Yellow as ground and sometimes blue - the same with the signal wires. If it worked before, the colours must be right. Can we see a photo of the pedal sensor?

I have just removed the crank and here are photos of the sensor and mag ring as requested.

Just found some for sale on Ebay and, as the cost is minimal, have ordered one just to try. Nothing to lose in the long run!

 

[chris301up]

Hi all. Think I've found the problem? Removed the sensor from the bottom bracket, stripped back the outer sheath, and discovered the red wire disconnected! Glad I ordered another now! Thanks all for your advice

 

[vfr400]

It looks OK, so must be a cable fault of broken sensor. they're not expensive, so get a new one.

Pardon our interruption...

I don't recommend fancy expensive ones because there can be compatibility issues. the cheap ones are the most compatible. Whichever one you get, check the wire sequence in the connector matches yours and adjust if necessary.

 

[vfr400]

Hi all. Think I've found the problem? Removed the sensor from the bottom bracket, stripped back the outer sheath, and discovered the red wire disconnected! Glad I ordered another now! Thanks all for your advice

You posted that while I was typing. I hope you ordered the right one, bearing in mind what I just posted.

 

[chris301up]

It looks OK, so must be a cable fault of broken sensor. they're not expensive, so get a new one.

Pardon our interruption...

I don't recommend fancy expensive ones because there can be compatibility issues. the cheap ones are the most compatible. Whichever one you get, check the wire sequence in the connector matches yours and adjust if necessary.

This is the one I decided to buy. 5 magnet ring and not expensive. Was only going to try it in the first place anyway at that price.

https://www.ebay.co.uk/itm/Electric-Bike-5-8-12-Magnet-PAS-Pedal-Assist-Speed-Sensor-Steel-Black-Durbale-UK/202753966886?
ssPageName=STRK%3AMEBIDX%3AIT&var=502891463162&_trksid=p2057872.m2749.l2649

 

[vfr400]

This is the one I decided to buy. 5 magnet ring and not expensive. Was only going to try it in the first place anyway at that price.

https://www.ebay.co.uk/itm/Electric-Bike-5-8-12-Magnet-PAS-Pedal-Assist-Speed-Sensor-Steel-Black-Durbale-UK/202753966886?
ssPageName=STRK%3AMEBIDX%3AIT&var=502891463162&_trksid=p2057872.m2749.l2649

That'll be OK. You might have to flip the disc or swap wires, though. Test it's operation before you reassemble the pedal to save a lot of work.