New Holland DCU 19722 – DCU (Dosing Control Unit / Denoxtronic Control Unit): EEPROM / Checksum failures | No corresponding variant number error | P062F Internal Control Module EEPROM Error

This is an internal memory error within the DEF (Diesel Exhaust Fluid) dosing system. The NOx neutralization unit (DEF supply module) is equipped with an internal cycle counter to verify the successful completion of the system's purge cycle (end run) when the machine is shut off. This cycle data is saved in the module's EEPROM memory. The 19722 fault triggers when the module attempts to save data to a protected memory area or detects a variant number mismatch, indicating software corruption or a physical failure of the EEPROM chip.

• New Holland T8 Series (T8.275, T8.300, T8.330, T8.360, T8.390, T8.410, T8.420, T8.435)
• New Holland T9 Series
• New Holland T7 Series
• New Holland T6 Series

1. 1

   Check for Tampering: Verify that there has been no unauthorized interference, aftermarket tuning, or 'DEF delete' software applied to the NOx neutralization unit or SCR system, as this can cause variant number mismatches in the EEPROM.

2. 2

   Software Reboot/Reflash: Connect the CNH Electronic Service Tool (EST). Perform a software reboot and attempt to reflash/update the DCU software to the latest version to see if the EEPROM can be successfully overwritten.

3. 3

   Wiring Inspection: Ensure the main power and ground harnesses to the DEF supply module are intact. Voltage drops or spikes during the shutdown/purge cycle can interrupt EEPROM writing and cause P062F checksum errors.

1. 1

   Clear codes and test cycle

   If the software reflash resolves the issue, clear the fault codes. Run the tractor, bring the exhaust up to operating temperature to initiate DEF dosing, and then perform a normal key-off shutdown. Wait for the DEF purge cycle to complete (listen for the pump running after key-off) to ensure the EEPROM saves the cycle counter correctly without throwing the code again.

2. 2

   Assess EEPROM damage

   If the DCU 19722 fault code is active and returns immediately after a software update, the internal EEPROM is permanently damaged.

3. 3

   Disconnect module

   Relieve any pressure in the DEF lines and disconnect the electrical harnesses and fluid lines from the DEF Supply Module.

4. 4

   Replace module

   Remove and replace the entire DEF Supply Module / Dosing Control Unit assembly.

5. 5

   Program new module

   The new replacement module is shipped blank or with generic software. It must be programmed/flashed to the specific vehicle variant using the CNH diagnostic tool after installation, otherwise, it will not communicate properly.