Liftmaster LA400 Gate Operator Strange Code 93 Issues - Check the batteries first!

My mother-in-law had a single gate with a Liftmaster Operator installed in 2016. For the last several months, she claimed, the opening/closing speed had dropped off. A few weeks ago, it stopped working completely.

I got out the troubleshooting manual and immediately started to learn the error codes. I was able to get it to partially move using the "move" buttons on the control board but would get a code 93, which basically means there's some sort of obstruction causing the arm to shut itself down to protect the motor. I even shorted the power leads to the motor directly and got the same behavior. 

I disconnected the gate end of the operator and made sure the gate swung freely, which it did. So I suspected that something in the arm itself was bad. So, I ordered a new arm for around $475 with shipping and tax. 

The new arm took a few days to arrive but once it did, I was certain the gate was going to be back to brand new. Well, it wasn't. In fact, I got the same behavior and error codes from the new arm as from the old. If I could get the gate to move at all, it was for a few feeble seconds then I'd get code 93. So I suspected the control board. Long story short, I installed a new control board and got the same results.   

I found a local Liftmaster dealer and tried to get a service call. Fortunately, after describing my issues to the salesperson, he said that low backup batteries can cause a host of strange codes to show up. After thinking on it, I realized that the motor runs on DC (duh) from the batteries which are kept charged by the AC line voltage. 

Since 2 new batteries cost about $45 with shipping and tax, I went ahead and ordered them. They arrived yesterday and I installed them (note: the old batteries had 1/8" spade terminals but the new ones came with 1/4" terminals - so I had to buy new crimp on connectors for the leads.) Thankfully, the gate jumped to life and I was able to program the limits and tie up every loose end...including programming the transmitter in my mother-in-laws 2019 Lexus to work the gate. 

Here's a link to the batteries: https://batteryclerk.com/products/liftmaster-la400-residential-12v-7ah-ups-battery You need to order two. 

 

The moral of the story is...don't be a dumbass. Ask for help early and, if you're getting strange codes, try replacing the batteries before any of the more expensive pieces. 

Now I'm off to ebay to sell a 2016 control board and LA400 motor/arm!