Error Code C2152 is a Transfer Belt Pressure / Retraction Failure on Konica Minolta bizhub colour machines. It fires when the machine commands the 1st transfer pressure/retraction mechanism to move — either pressing the transfer belt against the imaging drums for printing, or retracting it away from the drums between jobs — and the position sensor does not confirm that the movement completed within the allowed time.

Unlike most paper feed or motor errors, C2152 is specific to the transfer belt engagement mechanism. The transfer belt must press against and retract from the imaging drums precisely — staying pressed during printing and retracting during idle periods to prevent drum surface damage and toner contamination. When this mechanism fails, the machine stops to protect the drums and belt.

C2152 has significantly different component chains depending on the model family. What works on a C224e (CL5 clutch + PS39 sensor) is completely different from a C753 (M21 motor + PS51/PS52 sensors) or a C253 (CL7 clutch + PS31 sensor). Identifying your model before starting diagnosis is essential.

C2152 Has Different Components by Model Family — Identify Yours First

This is the single most important step before any diagnosis. C2152 involves entirely different motors, clutches, sensors, and connectors depending on the bizhub generation. Using the wrong references means checking components that have nothing to do with your machine’s fault.

What Does Error Code C2152 Mean?

On bizhub colour machines, the intermediate transfer belt (ITB) carries the toner image from the imaging drums to the paper. For this process to work correctly, the 1st transfer rollers must press the belt firmly against each imaging drum during printing, and retract away from the drums when printing is not occurring.

This press-and-retract action is performed by the 1st transfer pressure/retraction mechanism — a set of rollers on a cam-driven or motor-driven frame that moves the belt toward and away from the drums on command. The control board monitors this movement using a dedicated position sensor that confirms the mechanism has completed each movement within the allowed time.

C2152 fires under two conditions:

• Pressure failure: The control board commands the mechanism to press the belt against the drums (clutch ON or motor commanded), but the position sensor does not confirm the pressed state within the allowed time — the mechanism has not moved to the pressed position
• Retraction failure: The control board commands the mechanism to retract the belt away from the drums, but the position sensor does not confirm the retracted state — the mechanism has not moved back to the retracted position

Either failure prevents printing — pressing failure means toner cannot transfer correctly, and retraction failure means the drums continue to be loaded with belt contact when they should be resting.

Known Field Issue: bizhub C203 / C253 / C353 — CL7 Clutch and PS31 Sensor

1. PS31 detecting plate not fully operating the actuator arm: The modified white plastic detecting plate on the rear of the transfer belt assembly does not always fully trigger the PS31 actuator arm. Fix: add a spacer between the white plastic block and the metal plate to move it closer to the PS31 actuator arm. Insert one modification spacer between the White Colour Plastic Block and the Metal Plate, ensuring both projections are correctly set before refitting the M2 screw
2. CL7 clutch contaminated with rust or excessive grease: The CL7 clutch shaft is not rotating smoothly due to rust or grease contamination. Fix: remove the CL7 clutch assembly from the rear of the machine (requires removing PWB-MFP assembly and toner supply drive motor), clean or replace CL7 (part number A02E M200 00), and refit. If CL7 shaft still does not rotate freely after cleaning — check PRCB ICP7
3. Blown PRCB ICP7 — no power to CL7: Check ICP7 on the PWB-MC (printer control board, part number A02E H001 06) for continuity. An open-circuit ICP7 means CL7 receives no power. Replace PWB-MC if ICP7 is blown

Common Causes of Error Code C2152

• Transfer belt unit not fully seated after installation or service — the most common cause across all model families. When the transfer belt unit is removed and reinstalled (for cleaning, drum access, or unit replacement), it can be slightly misaligned. The pressure/retraction mechanism inside the unit is not correctly positioned relative to the sensor, causing C2152 on the first print cycle. Always the first thing to check
• Protective shipping tape or tab left on new transfer belt unit — a very common cause of C2152 immediately after installing a new transfer belt unit. New units ship with protective materials that must be removed before installation. A tab of foam or tape left on the pressure/retraction mechanism physically prevents it from moving, triggering C2152 immediately
• Loose or oxidized connector on CL5/CL7 clutch or position sensor — the connector between CL5 or CL7 and the PRCB/MFPB has poor contact. The clutch receives no engagement signal or only partial signal, and the mechanism does not move far enough to trigger the position sensor
• Failed or contaminated CL5/CL7 pressure/retraction clutch — the electromagnetic clutch that drives the pressure/retraction mechanism has failed or has insufficient magnetic force due to oil/grease contamination on the friction faces. The clutch slips or does not engage at all — the mechanism does not move despite the drive motor running
• Broken or worn transfer belt pressure/retraction gear — the cam gear that physically moves the pressure rollers has stripped teeth or a cracked hub. The motor runs and the clutch engages, but the gear cannot transmit force to the cam, so the rollers do not move
• Failed 1st transfer pressure sensor (PS39/PS31/PS51/PC6) — the sensor’s photo-interrupter has failed or its actuator flag is bent, broken, or misaligned. The mechanism reaches the correct position but the sensor does not confirm it, causing C2152 even though the physical movement is correct
• Failed 1st transfer pressure motor M21 (C654/C754) — on the dedicated-motor models, M21 has failed and cannot drive the pressure mechanism. Confirmed by a motor that does not respond to the service mode operation check with a confirmed drive signal
• Blown PRCB ICP5 or ICP24 (C654/C754) or PRCB ICP7 (C203/C253/C353) — inline circuit protectors on the PRCB feeding the motor drive or clutch drive circuit have blown, cutting power to M21 or CL7 regardless of their physical condition
• Transfer belt pressure roller gear misaligned after belt unit replacement — when a new transfer belt unit is installed, the pressure roller gear inside the unit must be correctly meshed with the machine’s drive gear. Incorrect gear mesh prevents the pressure rollers from moving to the correct position
• Faulty PRCB or MFPB — the control board cannot correctly drive CL5/CL7/M21 or read the position sensor — last resort

Step-by-Step Troubleshooting Procedure

Step 1 — Check Transfer Belt Unit Installation

This step resolves the majority of C2152 cases that follow a transfer belt unit replacement or any service where the unit was removed. It takes under five minutes and requires no tools.

1. Open the front cover of the machine
2. Locate the transfer belt unit — the large belt assembly spanning the full width of the machine above the tray area
3. If a new transfer belt unit was recently installed, check immediately for:
   • Protective shipping materials: Look for any foam pads, plastic tabs, adhesive tape, or protective sheets attached to the pressure/retraction mechanism on the underside or sides of the unit. Remove all protective materials completely before proceeding
   • Locking screws or transport locks: Some belt units have orange or blue transport locking screws that must be removed before the belt can operate. These are clearly labelled but are sometimes overlooked during installation
4. Check that the transfer belt unit is fully and correctly seated:
   • Pull the unit out slightly and push it firmly back in until it stops and the locking mechanism engages
   • On units with a locking lever, confirm the lever is in the locked position
5. Check the pressure roller gear engagement: the gear on the transfer belt unit must correctly mesh with the corresponding drive gear in the machine. Rotate the pressure/retraction mechanism manually — it should move smoothly through its full travel with even resistance
6. Power cycle and test — if C2152 clears, confirm correct operation with a few test prints

Step 2 — Manually Verify Pressure/Retraction Mechanism Movement

Before any electrical diagnosis, confirm the mechanism can physically move through its full range.

1. Power OFF the machine
2. Open the front cover and access the transfer belt unit
3. Locate the pressure/retraction cam gear on the transfer belt unit — this is a gear that, when rotated, causes the pressure rollers to move toward and away from the drums
4. Manually rotate this gear by hand through a full cycle:
   • The pressure rollers should smoothly move from the retracted position to the pressed position and back
   • The movement should feel smooth with even resistance throughout — no binding, sudden hard stops, or grinding
   • At both the fully pressed and fully retracted positions, the mechanism should have a clear end-stop feel
5. While rotating manually, observe the position sensor flag — it should enter and exit the sensor beam as the mechanism passes through each position
6. If movement is stiff, binding, or the mechanism cannot complete a full cycle:
   • Check for debris in the gear train
   • Check the cam for a cracked or stripped gear
   • On C203/C253/C353 with CL7: check whether the CL7 shaft rotates freely (see Known Issue section above)

Step 3 — Inspect and Reseat All Connectors

Use the model-specific connector references from the table above to reseat the correct connectors for your machine.

For bizhub C220 / C280 / C360:

1. Power OFF and unplug the machine
2. Reseat: M1 → PRCB CN14
3. Reseat: PS39 → relay CN124 → PRCB CN3
4. Reseat: CL5 → relay CN103 → PRCB CN24

For bizhub C224 / C284 / C364 family (including e-series):

1. Power OFF and unplug the machine
2. Reseat: M3 → PRCB CN2
3. Reseat PS39 sensor connector at the relay and at the PRCB end
4. Reseat CL5 clutch connector at the relay and at the PRCB end

For bizhub C654 / C754:

1. Power OFF and unplug the machine
2. Reseat: M21 → relay CN428 → PRCB CN4 — reseat at both relay CN428 and PRCB CN4
3. Reseat: PS51 → relay CN297 → PRCB CN6 — confirm PRCB CN6-1 signal is accessible
4. Reseat PS52 connector at the PRCB

For bizhub C203 / C253 / C353:

1. Power OFF and unplug the machine
2. Reseat M5 connector at PRCB
3. Reseat PS31 sensor connector
4. Reseat CL7 clutch connector at PRCB

For bizhub C250 / C252 / C300:

1. Reseat M1 connector at PWB-M (check at CNDM1-5/CNDM1-8)
2. Reseat CL3 connector at PWB-M (CNDM1-11)
3. Reseat PC6 sensor connector

Step 4 — Perform the Position Sensor I/O Check

The sensor I/O check tells you immediately whether the problem is that the mechanism is not reaching the correct position, or that the position sensor is not detecting it when it does arrive. This is the most important diagnostic step before replacing any component.

For bizhub C220/C280/C360:

1. Enter Service Mode → I/O check
2. Monitor PS39 at PRCB CN3-15 (ON)
3. Manually rotate the pressure/retraction cam gear to the pressed position — PS39 should switch to ON
4. Rotate to retracted position — PS39 should switch to OFF
5. If PS39 does not switch when the mechanism physically reaches position → replace PS39
6. If PS39 switches correctly manually but not during the motor-driven cycle → clutch CL5 is not engaging fully (proceed to Step 5)

For bizhub C654/C754:

1. Monitor PS51 at PRCB CN6-1 (ON), Location: 22-C
2. Also monitor PS52 at its PRCB reference
3. Manually actuate the pressure mechanism and confirm PS51 and PS52 both switch correctly at the pressed and retracted positions
4. The C654/C754 requires BOTH PS51 (for /K channel) AND PS52 (for /YMC channels) to confirm position — if either fails, C2152 fires

Step 5 — Perform Clutch and Motor Operation Checks

For clutch-based models (CL5/CL7 — most model families):

1. Enter Service Mode → operation check for the clutch
2. Command CL5 (or CL7) ON:
   • C220/C280/C360: CL5 operation check at PRCB CN24-4 (ON)
   • C250/C252/C300: CL3 operation check at MFPB/PWB-M CNDM1-11 (ON), Location: L-1/L-2
3. When the clutch is commanded ON, the pressure/retraction mechanism should begin to move immediately
4. Listen for the clutch engaging — you should hear a distinct magnetic engagement sound
5. If clutch commands ON but mechanism does not move → clutch is slipping or contaminated → remove and inspect CL5/CL7 for oil contamination or rust on the friction surfaces

For M21-based models (C654/C754):

1. Enter Service Mode → M21 operation check
2. Command M21 to run: PRCB CN4-5 to 8, Location: 3 to 4-K
3. M21 should run immediately and begin moving the pressure mechanism
4. If M21 does not respond with a confirmed drive signal present → check PRCB ICP5 and ICP24 (Step 6)

For all models — main drive motor check:

1. For clutch-based models, confirm the main drive motor (M1/M3/M5) is running when commanded:
   • C220/C280/C360: M1 operation check at PRCB CN14-2 (REM) and PRCB CN14-5 (LOCK), Location: C-2 to 5
   • C250/C252/C300: M1 operation check at MFPB/PWB-M CNDM1-5 (REM) and CNDM1-8 (LOCK), Location: L-2
2. A main motor that does not run means neither the pressure nor retraction mechanism can move — the clutch engaging is meaningless if no drive power is reaching it

Step 6 — Check ICP Continuity

For bizhub C654 / C754:

1. Access the PRCB and locate ICP5 and ICP24
2. Test both ICPs for continuity — no continuity confirms the ICP has blown
3. A blown ICP5 or ICP24 means M21 receives no power regardless of its own condition
4. Before replacing the PRCB, confirm M21 is not shorted — a shorted motor is what blows ICPs. Test M21 winding resistance and confirm it is not near-zero (short circuit) before installing a replacement board

For bizhub C203 / C253 / C353:

1. Access the PRCB (PWB-MC, part number A02E H001 06) and locate ICP7
2. Test ICP7 for continuity — an open circuit confirms ICP7 has blown
3. This is step 3 in Konica Minolta’s official bulletin for this model family (after checking PS31 detecting plate and CL7 clutch)
4. Blown ICP7 requires PRCB replacement

Step 7 — Clean or Replace CL5 / CL7 Clutch

If the operation check shows the clutch is commanded ON but the mechanism does not move, inspect the clutch itself.

1. Access the CL5 or CL7 clutch — on most models it is accessible from the rear cover area near the main drive assembly
2. Inspect the clutch friction faces for:
   • Oil or grease contamination — the most common cause of clutch slippage. Oil from nearby gearboxes can migrate onto the clutch friction surfaces, dramatically reducing its holding force
   • Rust on the magnetic engagement face — particularly on C203/C253/C353 where CL7 rust is a documented field issue
   • Physical damage — cracks in the clutch body or worn friction material
3. If contaminated: clean the friction surfaces carefully with isopropyl alcohol and allow to dry completely before testing
4. If contamination cannot be fully removed, or if the clutch shows physical damage: replace CL5 or CL7 with a genuine replacement
5. On C203/C253/C353 specifically: CL7 replacement part number is A02E M200 00

Step 8 — Replace the Transfer Belt Unit

If all connectors, sensors, clutches/motors, and ICPs are confirmed good but C2152 persists, the transfer belt unit’s internal pressure/retraction mechanism is faulty — a cracked cam gear, a broken return spring, or a mechanism that is mechanically seized.

1. Order the correct transfer belt unit for your model — part numbers differ by model generation and are not interchangeable
2. Power OFF and allow any residual toner to settle before removing the unit
3. Before installing the new unit, remove ALL protective materials — shipping foam, plastic covers, transport tapes, and transport locking screws
4. Install the unit firmly and confirm correct gear mesh between the pressure/retraction cam gear and the machine’s drive gear
5. Confirm the unit locking mechanism is fully engaged
6. After installation, power on and run a test print — confirm the belt presses and retracts correctly and C2152 does not return
7. Run a colour registration adjustment and gradation adjustment after transfer belt unit replacement

Step 9 — Replace the PRCB or MFPB

Board replacement is the final step and should only be performed after a confirmed-good transfer belt unit, confirmed-good clutch/motor, confirmed-good sensor, and confirmed-intact ICPs still produce C2152.

• PRCB — bizhub C220/C280/C360, C224/C284/C364 family, C452/C552/C652, C654/C754, C203/C253/C353
• MFPB (or PWB-M) — bizhub C227/C287/C367, C258/C308/C368, C458/C558/C658, 458e/558e/658e, C250/C252/C300/C350

Quick Reference — Troubleshooting by Symptom

Understanding the C215x Transfer Belt Error Family

C2152 belongs to a group of transfer-belt related errors that target different aspects of the belt’s operation. Understanding the family prevents misdiagnosis when multiple codes appear together:

• C2151 — Transfer belt motor drive malfunction (belt surface movement — M1/M3 not spinning the belt)
• C2152 — Transfer belt pressure/retraction failure (mechanism not reaching pressed or retracted position)
• C2160 — 1st transfer roller pressure error — Cyan channel
• C2161 — 1st transfer roller pressure error — Magenta channel
• C2162 — 1st transfer roller pressure error — Yellow channel
• C2163 — 1st transfer roller pressure error — Black channel
• C2164 — 1st transfer roller pressure error — combined
• C2204 — 2nd transfer pressure failure (belt-to-paper transfer pressure mechanism)

C2151 and C2152 appearing together means the belt is both not moving and not pressing correctly — almost certainly a connector fault affecting both the main belt drive motor and the pressure mechanism, or a severely seized transfer belt unit that the machine detected in two separate ways.

C2152 alone (without C2151) confirms the belt motor is running correctly — only the pressure/retraction mechanism is faulty. This is the most common presentation and means the motor and belt drive chain are fine; focus exclusively on the pressure mechanism components.

Preventing C2152 From Recurring

• Always remove all protective materials before installing a new transfer belt unit — create a checklist for new belt unit installation that includes checking for shipping foam, transport screws, and protective tapes. This single discipline prevents the most common cause of post-installation C2152
• Inspect and reseat the CL5 and PS39 connectors during every PM visit — the clutch and sensor connectors are in the transfer belt area and are subject to toner dust accumulation and thermal cycling. A 60-second reseat during PM prevents the gradual connector degradation that causes intermittent C2152 events
• Check the pressure/retraction gear for wear during transfer belt unit replacement — when replacing the transfer belt unit, inspect the internal pressure/retraction cam gear for tooth wear or hub cracking before installation. A new belt unit with a partially cracked cam gear will cause C2152 within a few thousand pages
• On C203/C253/C353: inspect CL7 during every PM — the documented CL7 rust and contamination issue on these models is a progressive failure. Checking CL7 rotation smoothness during each PM and applying correct lubrication where permitted prevents the sudden C2152 that requires an emergency service call
• Run colour registration and gradation adjustment after every transfer belt unit replacement — while this does not prevent C2152 directly, skipping these adjustments after a belt change causes colour quality problems that result in a return visit. Build these into your transfer belt replacement procedure as mandatory final steps

Professional Technician Summary

Error Code C2152 on Konica Minolta bizhub machines is a transfer belt pressure/retraction failure, and the diagnostic approach varies significantly depending on which model family you are working on.

On all models: the most common cause of post-installation C2152 is a new transfer belt unit with protective shipping materials still attached or a unit that is not fully seated. Check this before any electrical diagnosis.

On clutch-based models (C224/C284/C364 family, C220/C280/C360, C452/C552/C652): CL5 clutch contamination or a loose CL5 connector resolves the majority of hardware C2152 cases. The service mode clutch operation check combined with the PS39 I/O check identifies the fault within minutes.

On C203/C253/C353 specifically: follow the official KBA sequence — PS31 detecting plate → CL7 clutch contamination → PRCB ICP7 — before replacing any board. These three causes account for virtually all C2152 cases on this model family.

On C654/C754: the M21 motor and PRCB ICP5/ICP24 are the primary hardware suspects. Always check ICP continuity before ordering a replacement motor or board, as a blown ICP is significantly cheaper to address than either component.