Case IH 19723 – DCU (Dosing Control Unit / Denox Control Unit): EEPROM / Checksum failure

The control module is unable to properly read, write, or verify the data stored in its internal Electrically Erasable Programmable Read-Only Memory (EEPROM). The memory has either become corrupted, the checksums do not match the expected values, or there is a physical hardware failure on the module's circuit board.

• Tier 4a
• Magnum Series 235
• Magnum Series 250
• Magnum Series 280
• Magnum Series 315
• Magnum Series 340 (Series 4)
• Steiger / STX Series 350 through 600
• Puma Series
• Farmall Series

1. 1

   Check Battery and Charging System: Low battery voltage, voltage spikes, or a failing alternator can interrupt the DCU's memory writing process during key-off, causing corruption.

2. 2

   Inspect Wiring and Grounds: Check the main power, ground, and K15 (Ignition ON) signal wires at the DCU harness connector. Look for corrosion, moisture intrusion, or backed-out pins.

3. 3

   Attempt a Software Flash: Connect the CNH Electronic Service Tool (EST). Attempt to clear the code and perform a software update or re-download the dedicated data set to the DCU. If the EEPROM accepts the flash and the code clears, it was a software corruption issue. If the flash fails or the code immediately returns, the hardware is permanently damaged.

1. 1

   Disconnect Power

   Disconnect the tractor's negative battery cable to prevent electrical spikes during module replacement.

2. 2

   Locate the DCU

   The Dosing Control Unit is typically mounted near the DEF tank or the DEF supply pump module.

3. 3

   Remove the Faulty Module

   Disconnect the multi-pin electrical harness connectors from the DCU. Unbolt the module from its mounting bracket.

4. 4

   Install the New Module

   Mount the replacement DCU and secure the hardware. Reconnect the electrical harnesses, ensuring the locking tabs click into place.

5. 5

   Restore Power

   Reconnect the negative battery cable.

6. 6

   Program the New DCU

   A new DCU is blank. You must connect the CNH Electronic Service Tool (EST) and flash the module with the correct software dataset specific to the tractor's PIN/Serial Number.

7. 7

   Calibrate and Test

   Perform any required SCR system calibrations via the EST, clear all inactive codes, and run the engine to verify the DEF system builds pressure and the code does not return.