Brother Printer Error Code 37 — What It Means & How to Fix It

What Does This Error Mean?

Error 37 means there is a problem with the drum unit in your Brother laser printer. The drum unit is the component that transfers toner from the cartridge onto the paper. This error usually means the drum needs to be replaced or its counter needs to be reset.

Affected Models

Brother HL-L Series
Brother MFC-L Series
Brother DCP-L Series
Brother HL-L2350DW
Brother MFC-L2750DW

Common Causes

The drum unit has reached or exceeded its rated page count and needs to be replaced
The drum unit was replaced but the drum counter was not reset in the printer menu
The drum unit is not fully seated in the printer chassis and the printer cannot detect it
A non-genuine or incompatible drum unit was installed that the printer does not recognize
The drum unit's drum surface is damaged from exposure to light, fingerprints, or abrasion

How to Fix It

Open the front cover of the printer and slide out the drum unit and toner cartridge assembly.

On most Brother lasers, the drum and toner come out as one combined unit. Push the blue or green release tab to separate them if needed.
Check the drum unit's page counter label or the printer's menu to see if the drum has reached its rated life.

Most Brother drum units are rated for 12,000 to 30,000 pages depending on the model. Check the specs for your model.
If the drum is at the end of its life, install a new drum unit. Separate the new drum from its box and remove the protective film and packaging.

Do not touch the green or grey drum surface with your fingers — skin oils can permanently damage the drum.
After installing a new drum unit, reset the drum counter. On most Brother printers: open the front cover, hold the OK button for about 3 to 5 seconds, or go to Menu > Machine Info > Reset Parts Life > Drum.

The exact reset procedure varies by model. Check your printer's manual for step-by-step instructions.
Close the front cover and print a test page to confirm the error is cleared.

If error 37 persists after installing a new drum and resetting the counter, the drum sensor may be faulty — contact Brother support.

When to Call a Professional

Error 37 is almost always fixed by replacing the drum unit or resetting the drum counter. Drum units for Brother laser printers typically cost $20 to $60 and are user-replaceable. If the error persists after installing a new genuine drum unit, the printer's drum sensor may need service.

Frequently Asked Questions

Can I keep printing after error 37 appears?

The printer will allow limited printing after a drum warning on some models. Once the drum counter reaches zero and the error is active, printing will be blocked entirely. Replace the drum unit as soon as possible to avoid unexpected downtime.

Do I need to replace the toner when I replace the drum?

Not necessarily. On Brother printers, the drum unit and toner cartridge are separate consumables. You can install a new drum and keep using the existing toner cartridge if it still has ink. However, if you have a combined drum-toner unit (common on some models), both are replaced at the same time.

Why does my Brother show error 37 on a brand new drum?

The most likely cause is that the drum counter was not reset after installation. Follow the drum counter reset procedure in your printer's manual immediately after installing any new drum unit. If you reset the counter and error 37 still appears, the new drum may be incompatible or defective — try a genuine Brother drum.