Case IH P2E – Engine ECU or Transmission PCU: Battery Voltage, Shorted To Low Source

The voltage being supplied to the control module has dropped below the minimum acceptable operating threshold (typically <7V) or the power supply circuit has a direct short to ground. The engine is usually still enabled with no restriction on fuel or speed, but electronic shifting and sensor readings may become erratic.

• MXM
• Case IH MXM Series
• Case IH Puma Series
• Case IH Magnum Series
• Case IH AFX Series Combines

1. 1

   Perform a battery load test to ensure the batteries are holding a proper 12V charge and are not dropping voltage under load.

2. 2

   Inspect the battery terminals, crossover cables, and main chassis ground for heavy corrosion, looseness, or fraying.

3. 3

   With the engine running, verify that the alternator is outputting between 13.5V and 14.2V.

4. 4

   Disconnect the main harness from the ECU (e.g., Connector X193) and check the power supply pins (usually Pin 3) for corrosion, pushed-back pins, or moisture intrusion.

5. 5

   Use a multimeter to measure the resistance between the ECU power supply wire and the chassis ground to check for a direct short.

1. 1

   Disconnect Power

   Turn off the ignition and disconnect the negative (-) battery cable, followed by the positive (+) cable.

2. 2

   Clean Connections

   Thoroughly clean the battery posts and cable terminals with a wire brush. Reattach and tighten them to specification.

3. 3

   Trace the Harness

   Follow the main power harness from the battery/starter solenoid up to the Engine ECU. Look for areas where the wire loom may have rubbed against the frame, engine block, or transmission housing, causing the insulation to chafe and short to the metal (low source).

4. 4

   Repair the Short

   If a chafed wire is found, cut out the damaged section, solder in a new piece of matching gauge wire, and seal it with dual-wall adhesive heat shrink. Re-loom the harness and secure it with zip ties away from vibration points.

5. 5

   Check/Replace Relays

   Check the main power relays in the fuse box. A failing relay can cause a severe voltage drop. Swap the main power relay with a known good one of the same amperage.

6. 6

   Reconnect and Clear Codes

   Reconnect the battery cables. Turn the key to the ON position and use the tractor's H-Menu or an electronic service tool to clear the stored t2E fault code. Start the machine and verify the code does not return.