# 34251 : Incoming Mains Phase Missing **URL:** \ **Category:** General\ **Created:** [October 27, 2026, 12:36pm UTC](https://tech-community.robotics.abb.com/t/34251-incoming-mains-phase-missing/15201 "2026-10-27T12:36:01Z")\ **Posts on this page:** 2\ **Page:** 1
**Author:** ![bran21](https://avatars.discourse-cdn.com/v4/letter/b/7ab992/32.png) [@bran21](https://tech-community.robotics.abb.com/u/bran21)\ **Post date:** [October 27, 2026, 12:36pm UTC](https://tech-community.robotics.abb.com/t/34251-incoming-mains-phase-missing/15201/1 "2026-10-27T12:36:01Z")
Hello everyone, I am looking for some troubleshooting insight regarding the following error on an **ABB IRC5 controller** : `34251 : Incoming Mains Phase Missing` ![RobotError_IncomingMainsPhaseMissing](https://europe1.discourse-cdn.com/flex005/uploads/robotics1/original/2X/4/488e7b990279a0d0ee4d538aac37242df1027d92.png) Currently, the controller is completely powered OFF. I am hesitant to turn it back on out of concern that it might cause physical damage to the hardware components. **Sequence of Events & Timeline:** All of the following activities occurred yesterday: - **7:00 AM:** Formatted the IRC5’s SD card. - **9:00 AM:** Jogged the robot successfully and updated the revolution counters. Everything was operating normally. - **11:00 AM:** The robot was still functioning without any issues. - **2:00 PM:** Pushed new I/O changes to the controller and executed a warmstart. Immediately following that warmstart (at 2pm), I was completely unable to move the robot and was greeted with the `34251` error code. **My Questions:** - Could **any** of those configuration/software activities (specifically the I/O push or warmstart) have triggered this error? - Is it safe to power the controller back on, or should I perform physical voltage/cable checks while it is powered down? - What would you recommended be the next step in troublshooting for this error 34251? I would highly appreciate any advice, experiences, or insights you can share! Thank you! ---
**Author:** ![bran21](https://avatars.discourse-cdn.com/v4/letter/b/7ab992/32.png) [@bran21](https://tech-community.robotics.abb.com/u/bran21)\ **Post date:** [October 27, 2026, 12:45pm UTC](https://tech-community.robotics.abb.com/t/34251-incoming-mains-phase-missing/15201/2 "2026-10-27T12:45:15Z")
update: I decided to turn the controller back on and the **error is still present** (It only populated after I tried to turn the motors back on and jog robot (which it wouldn’t allow me to jog obviously). Anyone have any tips?