Case IH 12920 – MTA CCM or APH: Checksum Error for parameter 6

This code indicates that the mathematical validation (checksum) of the data stored for "parameter 6" in the controller's non-volatile memory has failed. This condition points to data corruption, a software glitch, or a failing internal memory chip (EEPROM) within the control module.

• MAXXUM T4E
• Case IH Farmall series
• Case IH Maxxum
• Case IH Vestrum
• Case IH Puma (Short Wheelbase)

1. 1

   Check System Voltage: Verify battery voltage and inspect the ground connections to the CCM/APH. Voltage drops or spikes during memory write cycles are a primary cause of EEPROM memory corruption.

2. 2

   Access On-Board Diagnostics: Use the dealer diagnostic lead to access the 'HH menu' (on-board diagnostics) to review the vehicle subsystem configuration and see if the parameter can be manually cleared or re-entered.

3. 3

   Attempt Calibration: Attempt to perform a full transmission/chassis calibration. Note: Calibration cannot proceed unless the tractor is completely stationary and the clutch pedal is released.

1. 1

   Connect Diagnostic Tool

   Connect the Case IH Electronic Service Tool (EST) to the tractor's diagnostic port.

2. 2

   Reflash the Module

   Reflash or update the software on the CCM / APH module. This will attempt to rewrite the corrupted memory blocks and restore the default parameters.

3. 3

   Recalibrate

   Perform a complete calibration of the transmission and armrest controls using the EST.

4. 4

   Power Cycle

   Cycle the key off and back on. If fault code 12920 returns immediately, the internal memory chip of the CCM/APH is physically damaged and cannot hold data.

5. 5

   Replace or Repair Module

   If the reflash fails, remove the CCM or APH module. You must either replace it with a new unit or send the original unit to an agricultural electronics specialist for board-level repair.

6. 6

   Program New Module

   If a new module is installed, use the EST to program the module to the tractor's specific configuration.