Ryobi RM480E 38" riding mower won't move!

Ask to speak to a technical support person, they seem knowledgeable and helpful. Shortly after I got mine 3 1/4 years ago, I had a stripped nut holding a blade on -- found it when swapping bagging blades. They FedEx'd one no charge. Unfortunately, recently I experienced the blades spin but no move problem, plus white smoke pouring out of left side. Black 'goo" was oozing out of the controller. Ryobi provided me with parts list and troubleshooting info. Since out of warranty I had to pay for controller myself (shop around, prices vary widely). I replaced the controller, it no longer smoked, but got a constant beep. Replaced the seat switch, no longer beeps, but still wont go. Traced it down to the drive motor -- Motor OK, but there are 3 Hall Sensors on a PCB, basically the equivalent of brushes that are used on brushless motors. Found out you can't buy just the drive motor, you have to purchase motor and whole differential. P/N's on hall sensors and PCB were useless (even had a friend fluent in Chinese try to determine a manufacture). After spending nearly $500 and countless hours, I determined it wasn't worth the additional cost plus looking a another $800. in batteries in a couple of years. It was good while it ran, but i am now parting it out on ebay.

Sorry for the long response... Just had to vent a little to.

At least I'm not alone, but this is scary....same issue. Would sometimes go and then stop. Sometimes could finish lawn. Now nothing. Purchased April 2, 2019. No service centers anywhere near me....

The forward reverse switch is not very good on these mowers. I replaced mine, but installed it backwards and I now go forward when in the reverse position.

Same exact issue I have. Mower moves briefly then stops i called ryobi they sent me an accelerator pedal switch.i installed and problem not solved. I called back and said I needed to go to a repair shop but likely cause is controller. They didn't offer to ship me a new controller, but I will call back and hopefully get one. It seems straight forward for install

Maybe this will help someone... I had a failure with a hall sensor on a drive motro & bad drive motor controller.

Testing Drive Controller Test for short circuit:

1. Set DMM to Resistance Mode.
2. Connect DMM red probe to red power cable
3. Connect DMM black probe to black power cable. Nominal resistance: 750K Ohms or more (or “Open”)

Check resistance in controller output:
1. Set DMM to Resistance Mode.
2. Check continuity between any two terminals (heavy Yellow and heavy Green for example).
3. Check continuity between two other terminals (2 and 3 for example).
4. The 2 measurements should be nearly identical. Nominal resistance: 18.5K Ohms Diode

Check Test Power and Ground Resistance at output circuitry
1. Set DMM to DIODE MODE
2. Connect black lead of DMM to heavy black wire (ground).
3. Sequentially connect red probe to each of the heavy Phase wires.
4. The measurements should be nearly identical. Expected reading : “OL” or “OPEN”
5. Connect black lead of DMM to heavy RED wire
6. Sequentially connect red probe to each of the heavy phase wires 7. The measurements should be nearly identical. Typical reading: 0.45V


Test Drive Motor
1. Set DMM to Resistance mode
2. Measure resistance between heavy green and heavy yellow wire.
3 Measure resistance between heavy green and heavy blue wire.
4. Measurements should be nearly identical -- Nominally 0.1 ohm

Testing Drive Motor Hall Sensors (in Mower)
Note: power should be ON and rear wheels raised so they can be rotated by hand.
Set DMM to “DC Volts”
1. Touch red probe to red wire.
2. Black probe to black wire.
3. Should measure 4-5V.
Leave black probe connected to black wire.
1. touch red probe to yellow wire Slowly rotate motor. Voltage should Jump between 0V and 4-5V.
2. repeat with green wire.
3. repeat with blue wire.

Note this test is conducted with coonnectors coneected and meter probes inserted into connecter shell.

No problems with my 480e yet but that's a lot of valuable info in here. Good to know.

I am having the same problem. Everything else works, headlights light up, blades spin up, even get reverse beeping sound when I flip the direction switch to reverse, it just won't actually move forward or backwards.
I found if I unplug the fuse that comes off the 12 v power converter (unit is under right rear tire, fuse extends up and is on the right side side of batteries, can access if you take rear panel off). Once I pull the fuse out and reseat, then it works again
I find this happens when I try to push the accelerator all the way down, or if there is extra load, like blades running and a bit of an incline where I have to depress pedal further to maintain speed.
My only guess is the drive unit is going out and some protect mode is kicking in, then when I reset the fuse to the 12 v power converter it resets the "safety".
If anyone actually finds the fix would love to hear what part of was for sure

I register just to share my experience. I had the same issues described here. 1.5 year old mower with only 32 hours on it. Would not go forward or backward but if I power cycled it would sometimes drive again for a few seconds or minutes even. I live in Los Angeles area where you'd think there would be plenty of service centers but nope, had to figure out a way to drive it 55 miles away. Ryobi's strategy to fix these is to send one repair part at a time to the shop to see if it fixes it, each taking about 2 weeks to send, install, and diagnose. I sent it in on February 8th and here we are 9 weeks later with no resolution. The worst part is the shop got it work temporarily and were about to have me pick it up but it failed again so it at least saved me having to spend a day getting it. I'll keep posted on what ends up fixing it.

Update:. I ordered the 996508001 DRIVE MOTOR CONTROLLER $275.41

This solved the problem and was very easy to replace. Again, my problem was that the mower would stop moving forward or reverse, but everything else on the mower would function. Power cycling off and on would reset it, allow me to drive again, but that usually would not last very long.

I bought the mower used from a guy that bought it new 2 1/2 years ago. What ticks me off is that while replacing the drive motor controller, i discovered it was not the first time it had been replaced. That means this mower is now on ts 3rd drive motor controller, at least, in only 3 years. That is terrible. Based on how many people here are saying they have this same problem, and knowing the people on this forum represent only a small fraction of owners, this has got to be a known issue. Ryobi really needs to step up and offer an updated part with longer life.

Dingo-J said:

Update:. I ordered the 996508001 DRIVE MOTOR CONTROLLER $275.41

This solved the problem and was very easy to replace. Again, my problem was that the mower would stop moving forward or reverse, but everything else on the mower would function. Power cycling off and on would reset it, allow me to drive again, but that usually would not last very long.

I bought the mower used from a guy that bought it new 2 1/2 years ago. What ticks me off is that while replacing the drive motor controller, i discovered it was not the first time it had been replaced. That means this mower is now on ts 3rd drive motor controller, at least, in only 3 years. That is terrible. Based on how many people here are saying they have this same problem, and knowing the people on this forum represent only a small fraction of owners, this has got to be a known issue. Ryobi really needs to step up and offer an updated part with longer life.

Click to expand...

Update to my update. Was able to mow the front yard no problem then it started doing the same thing, only now I can't get it to reset at all. It's become a push mower. Won't ever make the mistake of buying a Ryobi again.