![](https://publications.lexmark.com/media/ids_assets/images/transparent.png)
Power off the printer, wait for a few minutes and power it back on.
![](https://publications.lexmark.com/media/ids_assets/images/transparent.png)
Remove the toner cartridge and replace it with a known good cartridge. Observe if the error remains.
![](https://publications.lexmark.com/media/ids_assets/images/transparent.png)
Remove all the supplies (toner cartridge and imaging unit) from the printer.
![](https://publications.lexmark.com/media/ids_assets/images/transparent.png)
Power off the printer, wait for a few minutes and power it back on.
![](https://publications.lexmark.com/media/ids_assets/images/transparent.png)
Observe whether the printer posts a 31.xx and not 938.04A error after removing the supplies.
- Should the printer posts 31.xx, reinstall back the supplies one at a time (imaging unit first then toner cartridge) until the 938.04A error re-appears.
- Replace the defective supply once it is narrowed down.