Jam Code 66-03 is a document feeder transport section pre-feed obstruction fault on Konica Minolta bizhub machines equipped with an automatic document feeder. It belongs to the same 66-xx document feeder code range documented for Jam Code 66-02, but where that code addresses an original’s own transit timing through the DF’s initial feed section, 66-03 addresses a condition detected before the current original is ever advanced into the DF’s main transport section at all — the section that carries the original past the scanning position toward the DF’s exit. This is the DF’s own version of the pre-feed obstruction logic already established elsewhere in this series for the print engine’s second transfer section (30-03), paper exit section (32-06), and duplex transport section (93-03), applied here to the document feeder’s transport path.
The official Konica Minolta description states precisely:
The DF transport section’s entrance or internal relay sensor was detected in the blocked (ON) state during the pre-feed obstruction check performed before the current original was advanced from the feed section into the DF’s main transport path. The DF controller’s transport-section clearance check failed.
Translated into field language: before the document feeder advances an original past the initial feed section and into the main transport path that carries it across the scanning position, the DF controller performs a pre-feed check of the transport section’s own sensor chain — confirming that no original, fragment, or foreign object is already present there from a previous scan job or a previous incompletely-cleared jam. This check happens before the current original is advanced into the transport section. If the relevant sensor already reads ON at this check point, the DF controller withholds the advance and logs 66-03. In the large majority of 66-03 events, the current original never enters the DF’s main transport section at all — it remains in the feed section or is held at the transition point — while the actual obstruction is found within the transport section itself, left behind by an earlier job.
This distinction carries the same diagnostic weight established for every pre-feed obstruction code documented elsewhere in this series: 66-03 is not a statement about how the current original transported — it is a statement about what the DF controller found already sitting in the transport section before the current original was ever given the opportunity to enter it. A technician who receives a 66-03 call and immediately investigates DF transport roller condition, scanning-position timing, or exit mechanism function — the correct diagnostic path for a genuine transport-timing fault — is very likely investigating hardware the current job never actually exercised. The correct first question is the same one established for every pre-feed obstruction code in this series: what is currently sitting in the DF transport section that should not be there.
The DF transport section carries one consequence that has no equivalent anywhere else in this series and deserves particular attention: it passes directly across, or immediately adjacent to, the scanning position — the CIS module or the scanning glass strip that captures the document image. A fragment or foreign object left in this section is not merely a transport obstruction; if a subsequent original is driven across it, or if the fragment itself is dragged across the scanning glass during an incomplete jam-clearing attempt, it can scratch or deposit residue on the scan glass, producing a fine vertical streak defect on every subsequent scan or copy made using the DF until the glass is cleaned or repaired. This gives the pre-feed check — and the technician’s own fragment inspection — a print-quality dimension that the equivalent pre-feed checks in the print engine’s paper path do not carry.
| Field | Details |
|---|---|
| Jam Code | 66-03 |
| System | Document Feeder (DF / ADF) — the original-document scanning input path, distinct from the print engine’s paper path covered elsewhere in this series. Confirm the exact DF unit fitted (single-pass simplex, reverse-duplex, or a separate scanner-mounted ADF option) against the model-specific SM |
| General Category | Misfeed at DF/ADF Transport Section — the zone carrying an original from the initial feed section, past the scanning position, toward the DF’s exit. 66-03 is a pre-feed obstruction check performed against this section’s own sensor chain BEFORE the current original is advanced into it — not a transport-timing fault for the current original |
| What is and is not confirmed when 66-03 fires | Nothing about the current original’s transport through the DF’s main transport section is confirmed either way, because in most cases the current original was never advanced into that section — it remains in the feed section or held at the transition point. What IS confirmed is that the relevant transport-section sensor was reading ON at the moment of the pre-feed check — either from a genuine physical obstruction or from a sensor fault |
| Critical distinction from 66-01 / 66-02 (DF feed section codes) | 66-01/66-02 describe faults in the current original’s own pick and initial feed-section transit. 66-03 occurs at the boundary between the feed section and the main transport section, checking for a pre-existing obstruction in the transport section BEFORE the current original — already successfully picked and fed — is advanced any further |
| Critical distinction from a genuine DF transport-timing fault | If the model’s SM documents a separate code for an original that IS advanced into the transport section but then fails to reach the scanning position or the exit within a timing window, that is a distinct fault from 66-03 — refer to the model-specific SM to confirm whether such a code exists and how it is numbered, since 66-03 specifically addresses the pre-feed check, not the current original’s subsequent transport behavior |
| Elevated consequence specific to this zone | A fragment or foreign object in the DF transport section sits at or near the scanning position. Beyond the standard jam-obstruction risk, an uncleared fragment here risks contacting and marking the scanning glass/CIS strip, producing a print-quality streak defect on subsequent scans independent of the jam code itself. Careful, complete fragment removal is especially important in this specific zone |
| Detection Logic | Before advancing the current original from the feed section into the DF’s main transport path, the DF controller reads the state of the transport section’s entrance/relay sensor(s). If the relevant sensor reads ON (blocked), the controller withholds the advance for the current original, logs 66-03, and (per the model-specific SM) either holds the job or reports the fault for operator/technician attention |
| What is physically found when 66-03 fires — three scenarios | (A) A paper fragment or a substantially intact original from a previous, incompletely-cleared jam is physically present at or blocking the transport section’s entrance/relay sensor — the most common scenario. (B) No physical paper or fragment is found anywhere in the transport section, but the relevant sensor reads ON in diagnostic mode with the path visually and physically clear — sensor stuck ON, from a jammed actuator, contamination, or electrical failure. (C) The current original is found still in the feed section or at the feed-to-transport transition point, confirming the advance was withheld before it was ever attempted — directing attention entirely to the transport section itself |
| Key Components | DF transport section entrance/relay sensor (the sensor whose blocked pre-feed reading defines 66-03 — exact designation varies by DF unit, refer to SM); DF transport rollers (carry the original past the scanning position toward the exit); scanning position area (CIS module or scanning glass strip — adjacent to this transport zone and the reason fragment removal here carries elevated care); DF controller interface managing the pre-feed check logic and feed-to-transport advance gating |
| Severity | High for DF-based scan/copy jobs; the platen (flatbed glass) remains available as an alternative workaround while the fault is being resolved, since it does not use the DF transport path at all; may recur immediately after a jam clearing that appeared complete but left a fragment behind in the transport section — the most common field pattern for this code, consistent with every other pre-feed obstruction code documented in this series |
| Related Jam Codes | 66-01 / 66-02 (DF feed section codes — faults in the original’s own pick and feed-section transit, occurring before the point 66-03 checks), any DF exit/eject-section codes documented separately in the model-specific SM (refer to SM, as these cover the zone beyond this article’s scope), 30-03 / 32-06 / 93-03 (the functionally equivalent pre-feed obstruction checks applied to different zones of the print engine’s paper path — refer to those articles for the same underlying diagnostic logic) |
Model and DF Unit Coverage
As with every DF-related code in this series, document feeder internal layout, sensor designations, and exact check codes vary by DF unit model — single-pass simplex units, reverse-duplex units, and higher-capacity options all differ in their internal transport architecture. This article does not present a fabricated unit-by-unit component table with specific sensor names or connector references. Confirm the exact DF unit fitted to the machine, and use that unit’s own service manual documentation for every specific component designation and diagnostic-mode check code before beginning hands-on diagnosis.
Before beginning diagnosis, confirm from the applicable service manual:
- The exact designation and physical location of the transport-section entrance/relay sensor associated with 66-03 on this specific DF unit
- The physical access procedure for the DF’s main transport section, including safe access to the area adjacent to the scanning glass/CIS module without risk of contacting or marking that surface during inspection
- Whether the DF is a reverse-duplex design with its own internal switchback/reversal mechanism for second-side scanning, since this adds transport complexity and additional potential fragment-trap locations beyond a simple straight-through simplex design
- Any diagnostic-mode I/O check codes for the transport-section sensor(s) and drive components
ℹ️ The first two actions on every 66-03 call, before anything else: (1) Confirm the current original’s location — it will almost always be found in the feed section or at the feed-to-transport transition point, not within the main transport section itself. (2) With all paper removed from the DF transport section, check the relevant sensor state directly in diagnostic mode. If the sensor reads OFF once the zone is confirmed clear, the fault was a genuine physical obstruction that has now been resolved — proceed to a careful secondary inspection near the scanning position specifically (Step 3) given the elevated consequence of any residual fragment there, then close out the call. If the sensor reads ON despite the zone being visibly and physically clear, the fault is a sensor problem, not a paper problem — proceed directly to sensor diagnosis (Step 4).
Understanding the DF Transport-Section Pre-Feed Check — Why 66-03 Occurs
The pre-feed obstruction check that produces 66-03 exists for the same protective reason established for its counterparts elsewhere in this series: the DF controller will not advance a new original into a section that may already contain paper or debris from a previous event. For the DF transport section specifically, this protection carries the additional weight of protecting the scanning position itself — advancing an original across a fragment sitting at or near the scan glass risks not just a compounded jam but actual physical contact between the fragment and the imaging surface, which can produce a lasting print-quality defect independent of and outlasting the jam event itself.
The check itself is binary and pre-conditional, exactly as established for every pre-feed obstruction code in this series: it reads the current state of the transport-section entrance/relay sensor and either proceeds (clear) or withholds the advance entirely (blocked). Four root cause categories produce 66-03, ordered by frequency in field-installed document feeders, directly paralleling the category structure already established for 30-03, 32-06, and 93-03 and applied here to the DF’s specific hardware:
- Category 1 — Original document fragment left behind from an incompletely-cleared previous DF jam (dominant cause by a wide margin): A previous jam anywhere within the DF — in the feed section, the main transport section, or at the exit — was cleared, but a fragment was not fully removed. Given that DF units are frequently smaller and more compact than the print engine’s own paper path, with correspondingly tighter internal clearances, fragments here can be both more consequential (closer to the scanning position) and easier to overlook on a casual inspection. This category accounts for the substantial majority of 66-03 field events, with the identical diagnostic signature established for every pre-feed obstruction code in this series: the fault occurs on the very next DF job attempted after a jam was cleared
- Category 2 — Torn fragment specifically from a previous DF jam involving an aged or fragile original: A specific variant of Category 1 worth calling out given the DF’s exposure to a wide variety of original conditions (discussed in the 66-02 article): aged, brittle, or previously-damaged originals are more prone to tearing during a jam event or during jam clearing, leaving small fragments that are easy to miss, particularly given the reduced visibility typical of a compact DF’s internal layout compared to the print engine’s more open transport zones
- Category 3 — Transport-section entrance/relay sensor stuck ON from actuator jam, contamination, or electrical failure (no physical paper present): Confirmed by diagnostic-mode verification showing the sensor reading ON with the zone visually and physically confirmed completely clear
- Category 4 — Sensor harness or connector fault producing a false ON reading: Distinguished from Category 3 by testing the sensor directly at the sensor body where access allows, versus only observing the controller’s reading of it
Step 1 — Locate the Current Original
- Open the DF access cover(s) per the model/DF-unit SM
- Locate the current original — in the large majority of 66-03 events it will be found in the feed section or at the feed-to-transport transition point, not within the main transport section, confirming the advance was withheld before it was attempted
- Remove it carefully per the DF unit’s SM guidance if present
Step 2 — Inspect the DF Transport Section Thoroughly, With Particular Care Near the Scanning Position
- Following the DF unit’s SM access procedure, open access to the main transport section
- Inspect the entire accessible path systematically using a flashlight at multiple angles, exactly as established throughout this series for confined transport zones
- When inspecting near the scanning position (CIS module or scanning glass strip), use particular care. Do not use metal tools in this area. Do not apply pressure to or attempt to wipe the scanning glass/CIS surface itself as part of fragment removal — if a fragment is in direct contact with this surface, follow the DF unit SM’s specific guidance for safe removal without scratching or otherwise marking the imaging surface
- Remove any fragment found using non-metallic tweezers, working slowly in the confined space typical of DF internal layouts
- After removing any fragment, perform a second full inspection pass — a primary fragment often has smaller secondary fragments nested behind or beneath it, and given this zone’s proximity to the scanning position, a thorough second pass is worth the extra time
Step 3 — Verify the Sensor Reads OFF After Obstruction Removal, and Check for Scan Quality Impact
- With the zone visually confirmed clear, enter diagnostic mode and check the relevant sensor state directly
- Sensor reads OFF: The physical obstruction removal has resolved the fault. Close all covers and run a test scan/copy using the DF, checking the output specifically for any vertical streak defect that would indicate the scanning glass/CIS was marked or scratched during the original jam event or during clearing — if present, this requires separate scanning-glass cleaning or service beyond the jam code itself, per the model SM’s image-quality troubleshooting guidance. If no streak defect is present, run a 10-page DF test job to confirm 66-03 does not recur, and document the fragment found in the service log
- Sensor still reads ON despite the zone being visually and physically confirmed completely clear: Proceed to Step 4
Step 4 — Diagnose Sensor and Harness for a Stuck-ON Condition
- Inspect the actuator mechanism of the affected sensor, where applicable, confirming free range of motion and complete return to the home position
- For transmissive sensor designs, inspect for contamination on the emitter/receiver windows and clean thoroughly
- Reseat the harness connector for the affected sensor at the DF controller or relevant board, per the SM
- Where test access allows, verify the sensor’s actual state directly at the sensor body to distinguish a genuinely failed sensor from a harness/connector fault
- If cleaning, actuator inspection, and harness reseating do not resolve the stuck-ON condition, replace the affected sensor per the DF unit’s SM. Verify correct toggle behavior in diagnostic mode before running a full test job
Step 5 — Review Service History for a Recurrence Pattern
- Check whether 66-03 has occurred previously, and if so, whether each occurrence followed a jam clearing event in or near the DF within a short time window
- If a clear pattern exists — 66-03 recurring specifically after jam clearings performed by customer operators — this points toward a training/process gap. Consider providing customer key operators with guidance on thoroughly inspecting the DF’s internal path (not just the visible original) as part of standard jam clearing, and specifically flagging the elevated care needed near the scanning position
- If 66-03 has occurred multiple times with no clear connection to a preceding jam-clearing event, this points more strongly toward a recurring sensor or harness fault. Consider proactive sensor replacement if the pattern continues
Quick Reference — Troubleshooting by Symptom
| Symptom | Most Likely Cause | First Action |
|---|---|---|
| 66-03 on the first DF job attempted immediately after clearing a previous DF jam | Paper fragment left behind from the previous jam clearing — dominant cause | Inspect DF transport section with flashlight at multiple angles, with particular care near the scanning position; remove fragment with non-metallic tweezers; verify sensor reads OFF in diagnostic mode after removal |
| 66-03 with the current original found in the feed section, never having entered the main transport section | This is the expected, normal pattern for 66-03 — confirms the pre-feed check correctly withheld the advance | Direct all further inspection to the DF transport section, not to the feed section itself |
| 66-03 resolved after fragment removal, but subsequent scans show a fine vertical streak defect | The fragment or a prior jam event marked or scratched the scanning glass/CIS surface | Follow the model SM’s image-quality troubleshooting guidance for scanning glass cleaning or service, separate from the jam code resolution itself |
| 66-03 with no paper found anywhere; relevant sensor reads ON in diagnostic mode with the zone visually confirmed completely clear | Sensor stuck ON — actuator jam, contamination, or electrical failure | Inspect actuator mechanism; clean sensor window; reseat harness connector; replace sensor if stuck-ON persists after these checks |
| 66-03 recurring specifically after jam clearings performed by customer operators | Incomplete jam clearing within the DF’s internal path by untrained operators — a process/training pattern rather than a hardware fault | Confirm the immediate fragment is cleared; provide customer key operators with guidance on thorough DF inspection, with specific caution near the scanning position, as part of standard jam clearing |
| 66-03 recurring with fragments consistently traced to aged or fragile originals tearing during jams | Category 2 — original condition contributing to fragment generation during jam events | Advise customer on identifying poor DF candidates (aged, brittle, torn, or previously damaged originals) for platen-glass scanning instead, consistent with guidance established in the 66-02 article |
Understanding the 66-xx DF Jam Code Family
Jam Code 66-03 belongs to the 66-xx document feeder code family alongside 66-01 and 66-02:
- 66-01 — DF feed section primary misfeed — the original never reached the DF’s next feed-section sensor at all
- 66-02 — DF feed section late arrival — the original reached the next sensor, but later than the timing window allows (covered in a companion article)
- 66-03 — DF transport section pre-feed obstruction — the transport section’s entrance/relay sensor was found already blocked during the pre-feed check performed before the current original was advanced from the feed section into the main transport path. Not a transport failure of the current original; a pre-existing condition, almost always a fragment left behind from a previous event, or a sensor fault. This article
66-03 is the DF’s counterpart to 30-03, 32-06, and 93-03 documented elsewhere in this series, and all four codes share identical diagnostic logic applied to different zones. As with those codes, recognizing that the current original is generally not the subject of the fault investigation is what separates an efficient 66-03 diagnosis from one that wastes time investigating DF transport roller condition or scanning-position timing — none of which are relevant, because those systems were never given the opportunity to act on the current original.
Preventing Jam Code 66-03 From Recurring
- Provide customers with clear jam-clearing guidance specific to the DF, emphasizing thorough inspection of the entire internal path — not just the visibly jammed original — with explicit caution about the scanning position’s proximity to this zone
- When clearing any jam within the DF as a technician, always perform the full flashlight, multi-angle inspection described in Step 2 as standard practice, not only when 66-03 has already occurred, and always check for scan-quality impact afterward given this zone’s proximity to the imaging surface
- Include DF transport-section sensor cleaning in every PM visit
- Track recurrence patterns in the service log distinguishing jam-clearing-related 66-03 events from standalone, unexplained events, to determine whether the appropriate long-term fix is customer education or proactive sensor/harness replacement
Professional Technician Summary
Jam Code 66-03 is the DF transport section pre-feed obstruction fault — the DF controller’s routine check of the transport section’s entrance/relay sensor, performed before it advances the current original past the feed section, found the sensor already blocked and withheld the advance. This is not a statement about how the current original transported, because in the large majority of cases it was never given the chance to enter the transport section at all.
The dominant cause, by a wide margin, is a paper fragment left behind from a previous jam clearing. A thorough, multi-angle flashlight inspection resolves the majority of 66-03 calls with no parts required — but given this zone’s direct proximity to the scanning position, that inspection deserves more care and a more thorough second pass than the equivalent check elsewhere in this series, and should always be followed by a test scan to confirm no lasting image-quality impact from the original jam event.
When the zone is genuinely and completely clear but the sensor continues to read ON, the fault has shifted from a paper problem to a sensor problem — trust the diagnostic-mode reading and move directly to sensor and harness diagnosis rather than continuing to search a confirmed-clear zone.