Polaris 9550 does not work when submerged in water. Works on leslies diagnostics


Jan 18, 2017
Hi Folks,
I got a used 9550. It works at leslies with their dignostics tool. All 4 wheels spin. and teh controller checks out as good.
When submerged in water I get ER10 code on teh controller, and the cleaner wont move.

Per leslie it seems that the sensor that detects present /submerged in water is not functioning and sending the right signal.

any ideas what to do next.

is the sensor part of the drive assembly, or can I buy and replace seperately.
Coud something easy be the cause and what are the steps to try?



May 21, 2010
Hey LLP,

In my experience, my local Leslie's techs have absolutely no idea on how to fix these robots. Even though my local shop has the diagnostic tools, they totally gave me the wrong repair info, and quoted that I needed a new controller, cable and motor block and that the repair cost was going to be $1600. I got the idea that they were only interested in selling me a new one.

So, I've done a lot of research and worked on several units that I've now found I can restore.

The ER10 code means the controller can not talk to the motor drive block in the robot. The most likely cause is that the motor block flooded and is shorting out the board. Otherwise, there can be a broken connection involving the floating cable between the controller and the robot. There are 3 wires in the floating cable, one 28v DC, one ground and one signal carrying bi-directional data between the controller and the robot. As long as you do the simple stuff making sure the cable is connected well to the controller, chances are you have a flooded unit. A new motor block sells for about $400.

I have had some success in repairing these motor block assemblies, but not 100% since Polaris does not sell the individual components of the block. I have restored a few boards, and have good results in restoring flooded motors. Usually depends on how long the unit was exposed to water.

If you are interested, PM me. I'd be happy to try to restore your block, but you'd have to send the block to me (I'm in Northern CA). It's pretty easy to remove the block from the robot, so you'd not have to send the whole unit.