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HP LaserJet Classic Error Codes (10, 13, 20, 21, 40, 41, 50, 51, 52, 79): Fixes

HP Printer display showing GUIDE — FixCode Guide error code graphic

The two-digit codes are the LaserJet's original language — born in the service manuals of the 1980s and 1990s machines and still printed, largely intact, in today's user guides. This guide covers the classic core set — 10, 13, 20/21, 40, 41, 50, 51/52 and 79 — with HP's own definitions, the fix order HP's manuals prescribe, and the map that shows how each classic translates into the newer xx.xx.xx event format you may find in your printer's log.

Safety first. LaserJet safety is dominated by two things owners underestimate: mains electricity inside the covers, and the fuser. The fuser runs hot enough to fuse toner to paper and stays hot after the printer stops — HP's own fuser-error procedure builds in a cool-down (power off and wait at least 25 minutes before retrying on a 50.X that persists) — so never reach into the fuser area to pull a jam immediately after printing, pull jammed paper gently and in the direction of travel rather than tearing it backwards, and let a printer that smells of scorching cool, powered off, before investigating. Toner is a fine powder: avoid breathing it, vacuum spills only with a toner-rated vacuum (a household vacuum's filter passes toner and its motor can be damaged by it), and wash spilled toner off skin with cold water — hot water sets it. On all HP printers: unplug before any covers-off work, never defeat cover interlocks to watch the mechanism run, and treat formatter, power-supply and fuser replacement as service work. Ink models add small cautions of their own — do not leave cartridges out of the printer for more than 30 minutes (HP's warning in its contact-cleaning steps), and never press down on a closed printhead latch on ink-tank models (HP flags this in its carriage-jam steps).

How the classic table works — and why the model still matters

The classic LaserJet codes are a subsystem index: each number names the part of the printer that reported the fault. Supplies live at 10, paper movement at 13, memory and page processing at 20-22, communications at 40, temporary print errors at 41, firmware at 49 and 79, the fuser at 50, the laser/scanner at 51 and 52, the engine and its motors and fans at 53-58, memory hardware at 62-68, and the network/EIO family at 80-82. Learn that geography and a code you have never seen still tells you where to start. The table's second trait is longevity with drift. HP has carried these numbers through four decades of hardware, and while the core meanings are remarkably stable — 50 has meant the fuser since the LaserJet II — individual codes have acquired suffixes (50.X, 51.XX, 13.XX.YY) and, in a few documented cases, shifted meaning between generations, as the hub table notes for 57 and 81. The rule that keeps you safe is the rule HP's own structure implies: read your model's user guide table first, because it is the edition of the classic table written for your hardware; use this guide for the shared core, and treat any third-party chart that ignores model scope as suspect. The third trait is the action language the codes carry with them. Classic messages come in three severities, and the display tells you which you hold: continuable messages offer 'To continue press OK/Go' (acknowledge and print on, accepting possible data loss); 'Turn off then on' messages ask for a power cycle and escalate to service only if they persist; and service messages name themselves. Matching your response to that severity — neither ignoring a fuser code nor booking a technician for a continuable buffer message — is most of classic-code literacy.

10 — supplies memory error (the cartridge's e-label cannot be read)

Code 10 opens the table with the supplies system. In current HP user guides it appears as '10.XX.YY Supply memory error' (M3027 guide) or '10.X Supply memory error' (P2055 guide), and both define it the same way: the device cannot read or write to the print cartridge's e-label (the cartridge's memory chip), or the e-label is missing from the cartridge. Every modern HP toner cartridge carries that chip; it identifies the cartridge and tracks its state, and 10 means the conversation between printer and chip has failed. HP's recommended action is short: reinstall the print cartridge, or install a new HP print cartridge. On the P2055-era table there is one more option: press OK to override the error and continue to print, accepting that supplies and status features are not available — the printer will print blind, without knowing the cartridge's state. The diagnosis around the short action matters. A 10 that follows a cartridge change belongs to the new cartridge until proven otherwise: reseat it first (a chip that is a fraction out of alignment reads as missing), try the previous cartridge if you still have it, and check the chip's contacts for damage or contamination. A 10 on an untouched cartridge that has printed happily for months points the other way — at the printer's chip-reader contacts or the cartridge's chip failing in place. HP's guides also carry the related 10.32.00 'Unauthorized Supply' message, which is a different report (a fitted supply that fails HP's authentication test) with a different action — touch OK to continue printing — and conflating the two wastes a cartridge: memory error means the printer cannot read the chip; unauthorized supply means it read the chip and did not accept it.

13 — the jam family (and how its suffixes name the location)

13 is the paper-path code, and the one owners meet most. In the classic table it is simply a jam; in every later edition it grows suffixes that name where the paper stopped, and reading them is the skill. The M3027 guide's edition shows the pattern: '13.XX.YY — Jam in Tray 1', 'Jam in Tray X', 'Jam inside duplexer', 'Jam inside front door', 'Jam inside rear bin', 'Paper wrapped around fuser'. The newer xx.xx.xx event form extends the same logic — the 13.B2 group is the registration/top-cover family, with its final group resolving to the tray or location (13.B2.D2 is Tray 1; see the hub table). Three jam disciplines apply across all editions. First, clear where the code says, not where you first looked: a jam message names the sensor that saw paper stop, and paper can sit in the named location even when the obvious tray looks clean. Second, remove paper whole and in the direction of travel; a sheet that tears leaves a remainder that re-triggers the same code, and the 'jam that will not clear' is very often a fragment plus a sensor that is honestly still seeing it. Third, respect the repeat: HP's tables route a persistent 13 to support after the location is cleared, because a jam code with no paper anywhere is a sensor or flag fault — the top-of-page and registration sensors and their flags are small parts that stick after rough jam removals. Paper quality is the silent variable in every edition: HP's jam procedures end by checking that the media meets HP's specifications for the printer, that trays are configured for the loaded size and type, and that guides sit at the correct indentations — a tray configured for the wrong size manufactures jams that no amount of clearing fixes.

20 and 21 — memory and page complexity (the page the printer could not build)

Codes 20 and 21 are the rendering pair, and they are continuable by design. The M3027 guide defines 20 exactly: 'Insufficient memory — the device received more data than can fit in the available memory. You might have tried to transfer too many macros, soft fonts, or complex graphics.' Its action: touch OK to print the transferred data (some data might be lost), then simplify the print job or install additional memory. Code 21, 'Page too complex', is the timing twin: 'The page formatting process was not fast enough for the device' — touch OK to print the transferred data (some data might be lost), and if the message appears often, simplify the print job. The 2200 service manual's edition of 21 (print overrun) matches: the job was too complex for the available memory; press Go to resume; simplify the image or print at a lower resolution; add memory if it persists. The distinction worth keeping: 20 is capacity (the data does not fit), 21 is processing (the page cannot be composed at engine speed) — but the remedies converge, because both are the job outgrowing the machine's formatter resources. Practical fixes in HP's spirit: print the complex document in smaller sections, reduce graphic resolution, print PDFs as image where the driver offers it, switch from a PostScript driver to PCL (or the reverse) for a job the other language renders more cheaply, and fit the additional memory HP names if 20/21 are a weekly event on genuinely complex work. A single 20 or 21 on an unusually heavy file is information, not a fault: the printer told you its limit and offered to print what it had. Recurring 20/21 on ordinary documents, on a machine with adequate memory fitted, deserves the configuration check (is the printer's memory fully recognised on its configuration page?) before any purchase.

40 and 41 — transmission errors and temporary print errors

Codes 40 and 41 are the classic table's 'something went wrong in the conversation or the moment' pair, and both are explicitly temporary in HP's text. Code 40 in the 2200 service manual's secondary-code table is the 'Bad connection' case: the connection between the printer and the EIO card is bad — press Go to clear the error message and continue printing; if the message persists, turn the printer off and reseat the EIO card; replace the EIO card if it still persists. The older literature's 40 also carried the serial-transmission form ('40 BAD SERIAL TRANSMISSION': verify cable connections, make sure the printer's serial configuration matches the computer's baud settings, press GO to continue). Either way, 40 is about data arriving badly between two connected things — host and card, computer and serial port — not about the print engine. Code 41 is the temporary print error: the 8100-era service table lists 41.x as 'a temporary printing error occurred — press GO; the page containing the error will automatically be reprinted', with the sub-meanings spelled out (41.1 unknown misprint, 41.2 beam detect malfunction, 41.3 unexpected/improper paper size, 41.4 no video sync, 41.5 noisy video sync), and the P2055 table's 41.2 'Engine error' entry gives the generic modern handling (power off, wait at least 30 seconds, power on and initialise; remove any surge protector). The owner pattern for both codes is therefore calm: acknowledge and continue; a one-off 40 or 41 is a hiccup HP built the 'press Go' door for. Recurrence is what changes the meaning — repeated 40s point at the card, cable or serial configuration as a standing fault, and repeated 41.2s (beam detect) point at the laser/scanner connections the service table tells you to reseat before replacing anything.

50 — the fuser error (the one code to treat with respect)

Code 50 is the fuser family — '50.X FUSER ERROR' in every edition from the LaserJet 3200m guide to the P2055 table — and HP's text for it is the most safety-conscious in the classic table. The fuser is the heated assembly that bonds toner to paper; a 50.X means the product has experienced an error with the fuser. HP's recommended action in the P2055 guide is a staged cool-down, and it is worth following literally: turn the product power off, wait at least 30 seconds, and turn it on and wait for it to initialise; if the message persists, turn the product off, wait at least 25 minutes, and then turn it on — the long wait lets an overheated or thermally confused fuser return to a state where its temperature sensing reads honestly. Remove any surge protector and plug the product directly into the wall socket (HP repeats this because fusers draw heavy current and a marginal protector can starve them). If the message still persists, HP's instruction is support/service. The legacy guides agree: disconnect the power cable, wait at least 30 seconds, reconnect and initialise; if the message does not clear, the product will need service. The service-manual layer (2200) adds the technician's order for a persistent 50: be sure the fuser is installed correctly and fully seated, reseat the fuser cables, replace the fuser, then the engine controller, then the power supply. Owners should take two things from that order: a fuser that was just refitted after a jam or maintenance is worth one careful reseat before any part is bought, and everything after the reseat is internal service work around the printer's hottest, highest-current assembly. A 50 that arrives with a burning smell, scorch marks on pages, or repeated breaker trips is not a troubleshooting exercise at all — power off, leave it off, and book the visit.

51 and 52 — laser error and scanner error (the imaging beam pair)

Codes 51 and 52 guard the laser scanning system — the optics that write the page image onto the drum — and HP's tables keep them adjacent because they are two failure points in one assembly. In the legacy user guides they appear as '51 LASER ERROR' and '52 SCANNER ERROR', each defined as an internal hardware error with the family's standard action (disconnect power at least 30 seconds, reconnect, initialise; if the message does not clear, the product will need service). The 2200 service manual gives the pair their precise names: 51 is the 'Bad beam detect error' — the printer cannot confirm the laser beam's timing signal — and 52 is the 'Scanner error' — the scanner (the rotating polygon mirror motor system that sweeps the beam) has faulted. The P2055 table folds them into '51.XX Error — the product has experienced an internal hardware error' with the same power-cycle action. The service actions behind the brevity: for both 51 and 52, the 2200 manual's order is to press Go (the page containing the error will automatically be reprinted), and if the error persists, turn the printer off and reseat the laser/scanner cables, then replace the laser/scanner assembly, then the engine controller. That order teaches the owner's lesson: a single 51/52 after a move, a jam clearance or other physical disturbance can be a connection that needs reseating — but reseating laser/scanner cabling is covers-off work on most models, and the assembly itself contains the laser, which is why HP's user-level documentation stops at the power cycle and routes persistence to service. Never attempt to run a LaserJet with covers open to watch the scanner: the laser is invisible-beam hardware interlocked for a reason. Print quality can foreshadow this pair — pages with missing bands or a scanner that sounds wrong on startup — and a 51/52 that follows such symptoms is the assembly announcing its end, not a glitch to be cycled away.

79 — the service/firmware error (and its relationship to 49)

Code 79 is the classic table's general service error, defined in the LaserJet 5 manual as '79 SERVICE (XXXX): the firmware has detected an unrecoverable error. The numbers following the error indicate the specific kind of error.' Its documented action: switch the printer off, then back on; if the error appears again, record the numbers following the error message and call your dealer or HP service representative. The LaserJet 4 service manual's edition agrees — an internal controller error has occurred — and adds causes owners should know: it may also be caused by driver or application incompatibilities, or a defective toner cartridge, and third-party memory should be removed as part of the response. The P4015-era table renders it '79.XXXX ERROR — the product detected a critical hardware error' and prescribes the isolation flow that defines mature 79 practice: press Stop to clear the print job from memory, power off and on, try printing from a different program (and a different file) — if the message appears only with a certain program or job, the software vendor is the fix; if it persists across programs, disconnect all network/computer cables, remove add-on memory and EIO devices one by one, and rebuild until the culprit is found. Owners ask how 79 differs from 49, its deep-dive sibling on this site. Read them as cousins with different centres of gravity: HP's 49 text centres on the formatter aborting on data — invalid commands, corrupt data, invalid operations — so 49 diagnosis starts with the job; HP's 79 text centres on the firmware detecting an unrecoverable error and explicitly invites hardware and accessory isolation, so 79 diagnosis starts with what is fitted to the printer. In practice the two overlap (a corrupt job can surface as either on different models), and the shared disciplines — record the full suffix, clear the queue, isolate accessories, update firmware — serve both. The suffix after 79 is not decoration: HP's instruction to record it and quote it is the one action every edition agrees on.

From classic to event format: how the same faults are written today

A printer built in the last decade may show you the classic number on its panel and log a different, longer string for the same event — and knowing the translation stops you treating them as two faults. The xx.xx.xx format is structured: the first group is the classic subsystem number, and the later groups add location, sub-assembly and condition detail that the two-digit form never carried. Jams are the clearest example: panel '13' becomes a family of event codes — the 13.B2 group for the registration/top-cover area with the final group naming the tray (13.B2.D2 = Tray 1) — and the configuration/event-log machinery documented for these models (PRINT EVENT LOG in the menus; the last three entries summarised on the configuration page) stores the long form. The motor family shows the same dress change: 59.F0 in the log can appear as 59.00.F0, with the middle groups at zero because no narrower sub-location is being reported. Firmware keeps its classic face most stubbornly: 49 appears both ways, and HP's own M5035 document shows a machine whose panel was stuck on a logo while its Embedded Web Server displayed 49.4C02 — one fault, two windows onto it. Three working rules follow. Quote the long form when you have it: it is the more precise identifier, and HP's service side keys to it. Do not sum the forms: a panel 13 and a logged 13.B2.D2 from the same jam are one event, and a fault history that seems to show 'dozens of different codes' is often three faults wearing both dresses. And expect the classic table to keep shrinking at the edges: codes tied to vanished hardware (EIO slots, SIMM memory, serial ports) survive in legacy manuals but not in new models' tables, while their subsystems reappear under event groups (the 8501 Repair Manual's table, for instance, lists 80.WX.YZ as the embedded Jetdirect family and 82.WX.YZ as disk hardware) — the geography endures even as the street names change.

Key takeaways

Severity is printed with the code: 'press OK/Go to continue' means continuable, 'turn off then on' means cycle once and escalate only if it persists, and 'SERVICE' plus a suffix means record the suffix and start isolation.
A jam code names the sensor's location, not your first guess — clear where the suffix points (13.B2.D2 is Tray 1), remove paper whole, and treat a code that survives a provably clear path as a sensor fault.
50 is the exception to casual power cycling: follow HP's staged waits (30 seconds, then 25 minutes) exactly, plug direct to the wall, and stop entirely if there is any smell of scorching.
Keep the suffixes: 49.XXXX and 79.XXXX numbers are the evidence HP asks for, and the event log (PRINT EVENT LOG) holds the long form even when the panel shows the short one.

Resetting the HP printer

HP's documented reset for its printers is a power reset, and HP repeats the same procedure in document after document (ink-system errors, blue screens, E6/E8 states, event codes): with the printer turned on, disconnect the power cord from the rear of the printer; unplug the power cord from the power source; wait at least 60 seconds; reconnect the power cord to a wall outlet and to the printer — HP expressly recommends plugging the printer directly into a wall outlet rather than a surge protector or power strip — then turn the printer on and wait until it is idle and silent. For ink models HP's ink-system flow adds one step before the reset: remove the ink cartridges first, perform the power reset, and only reinsert the cartridges after the printer powers back on, printing a calibration/alignment page if prompted. Two things a power reset is not: it is not a factory restore (on touchscreen models that is a separate, documented action — Setup > Printer Maintenance > Restore > Restore Factory Defaults — which returns settings to defaults and is HP's step for persistent firmware-crash screens, not a first move), and it is not a cure for a standing fault. Any code whose cause is still physically present — a jammed sheet, a stalled carriage, a failed printhead, a transfer belt that cannot move — is re-detected at the next self-check and returns, which is the printer working as designed.