HP LaserJet M436 / M438 Replace TR Roller Reset: Tech Mode Diagnostic Guide

Written by: Helen J. Halladay, Printer Repair Technician

Bench-tested on: HP LaserJet MFP M436nda

Quick Answer

The “Replace TR. Roller” or “Prepare TR. Roller” warning on HP LaserJet A3 MFP printers indicates that the transfer roller maintenance count has reached its rated duty cycle (HP rates this at approximately 100,000 A4/Letter-equivalent simplex pages). An HP Replace TR Roller Reset is performed via the technician Tech Menu by navigating to Maintenance Counts and clearing the Transfer Roller register using the service sequence 10043616. Clearing the Transfer Roller count removes the maintenance-life warning after the roller has been replaced or properly serviced. It does not resolve a C9-2220 hardware fault caused by incorrect seating or a transfer-circuit problem.

Applies To

• Bench-tested Configuration: HP LaserJet MFP M436nda.

• Officially Documented / Same Engine Family: HP LaserJet MFP M433a, M436n, M437n, M438n / M438dn / M438nda, M439n / M439dn / M439nda, M440n / M440dn / M440nda, M442dn, M443nda.

• Target Component: Transfer Roller Kit, HP part number W7U01-67901.

Symptoms

• Depending on firmware and HP documentation revision, the maintenance warning may appear as C9-2110/C9-2120 or C9-2210/C9-2120 (“Prepare TR. Roller” / “Replace TR. Roller”).

• Hardware fault code C9-2220 (“TR Failure” or “Install TR roller again”) appears when the transfer roller is not correctly installed or when a transfer-circuit fault remains active.

• The status indicator light turns solid or blinking amber/orange.

• Printing may temporarily continue, but the maintenance message persists across reboots.

Likely Causes

1. Maintenance Life Reached: The engine has accumulated approximately 100,000 pages, reaching the rated threshold of the Transfer Roller Kit (W7U01-67901).

2. Unreset Component Replacement: A new Transfer Roller was physically installed, but the maintenance count was not cleared in the Tech Menu.

3. Transfer Roller Seating or Electrical Fault: Loose physical seating, contaminated electrical contacts, or high-voltage bias issues (flagged by code C9-2220).

Before You Start

• High-Voltage Safety: The transfer roller conducts high-voltage DC bias during toner transfer. Always power off and unplug the printer before opening access covers to inspect the transfer assembly.

• Print Quality Impact: Resetting the counter without addressing a worn roller will not restore toner attraction, leading to progressively lighter text or background haze.

• Keypad Input: The machine’s physical alphanumeric keypad is required to execute the service sequence.

Diagnosis Before Resetting

Before clearing firmware counters, inspect the paper path and roller assembly:

1. Power off and disconnect the main AC power cord.

2. Open the right-side access door to locate the black transfer roller mounted along the paper registration path.

3. If loose toner dust is visible around the transfer area, clean the surrounding paper path according to HP service guidance. Avoid touching, rubbing, vacuuming, or contaminating the conductive roller surface directly unless the exact service procedure specifically instructs it.

4. Inspect the physical roller for surface gouges, flattening, uneven wear, or heavy contamination. If damaged, replace the Transfer Roller Kit (W7U01-67901).

5. Ensure the transfer roller is fully seated in its mounting points and that no visible contact or locking component is displaced. Close the door, reconnect power, and proceed to the reset steps below.

Step-by-Step Tech Mode Reset Procedure

This procedure executes a direct maintenance counter clearance across the supported HP LaserJet M433–M443 architecture.

Step 1: Access the Service Tech Menu

1. Ensure the printer is powered on and in its idle Ready state.

2. Press the physical Menu button on the control panel.

3. Press the Hash (#) key.

4. Type the 8-digit service code on the numeric keypad: 1 0 0 4 3 6 1 6.

5. Press the Menu button once more.

6. When Tech Menu appears on the display, press OK.

Step 2: Navigate to Maintenance Counts

1. Scroll through the Tech Menu using the arrow keys (< or >) to locate Maintenance Counts.

2. Press OK to enter.

3. Scroll to Clear Counts and press OK.

Step 3: Enter Verification Passcode

1. When the Clear Counts menu prompts for authorization, enter the maintenance passcode sequence specified for this engine: press Menu -> # -> 1 0 0 4 3 6 1 6 -> Menu.

2. Complete the passcode sequence and follow the control-panel confirmation prompt to access the maintenance-item list.

Step 4: Execute the HP Replace TR Roller Reset

1. Scroll through the itemized counter list until Transfer Roller appears on the display.

2. Press OK.

3. When the screen asks for confirmation (e.g., [Clear?] or Transfer Roller: Yes / No), select Yes using the arrow keys.

4. Press OK to execute the reset.

5. Expected Outcome: The stored maintenance count for the Transfer Roller is cleared and the replacement warning should no longer be active.

Step 5: Exit and Power Cycle

1. Press the Back or Exit key repeatedly to back out of the Tech Menu.

2. Power off the printer, then power it back on to confirm that the maintenance warning has cleared.

3. Expected Outcome: The machine boots directly to the “Ready” state without displaying the “Replace TR. Roller” prompt.

How to Verify the Repair

1. Confirm that the transfer-roller maintenance warning or C9-series life code no longer appears on the control panel after boot.

2. Print a Configuration or Supplies Information report (Menu -> System Setup -> Report -> Supplies Info).

3. Where the firmware exposes maintenance-life information in the Supplies Information or service counters, verify that the Transfer Roller count has been reset.

If Issues Persist