Case IH 522838-05 - PCM – PCM: Internal backup battery disconnected

The internal lithium-ion backup battery inside the telematics module is either physically unplugged, completely depleted, or failing to communicate/provide backup power to the ECU.

• MAGNUM AFS Connect
• Magnum
• Steiger
• Optum
• Puma
• Axial-Flow 150
• Axial-Flow 240
• Axial-Flow 260
• Axial-Flow 7260
• Axial-Flow 8250
• 50 Series Patriot

1. 1

   Check Unswitched Power: Verify the cab unswitched power fuses for the display and the PCM. The absence of unswitched power can cause the module to rely entirely on the backup battery, draining it and triggering power faults.

2. 2

   Verify Main Disconnect Usage: Ensure the machine's main battery disconnect switch is being used correctly during off-season storage. Improper storage can permanently drain and damage the internal backup battery.

3. 3

   Physical Inspection: Inspect the PCM to ensure the internal battery harness hasn't vibrated loose or become physically disconnected.

1. 1

   Power Down

   Turn off the machine and engage the main battery disconnect switch to cut chassis ground and main power.

2. 2

   Locate the PCM

   Access the Processing and Connectivity Module. Exact placement differs by cab design, but it is typically mounted flat at the highest possible point of the vehicle cab/roof area, near the dual-mode cellular/GNSS antennas.

3. 3

   Access the Battery

   Open the battery access panel/compartment on the PCM.

4. 4

   Remove the Old Battery

   Disconnect the small wiring harness connecting the internal lithium-ion battery to the ECU board and remove the battery.

5. 5

   Install the New Battery

   Plug in the new OEM lithium-ion battery and secure it in the housing.

6. 6

   Reassemble and Power Up

   Re-secure the PCM and turn on the main battery disconnect.

7. 7

   Software Check

   Turn the key on and verify the display. If the PCM completely lost its memory due to the dead backup battery, the display and PCM may need to be re-synced or reprogrammed using the Electronic Service Tool (EST) base software via a USB memory device.