Case IH P7D – PCU (Pump Control Unit): EEPROM In PCU, Data Valid But Above Normal Range

This code indicates that the EEPROM chip inside the Pump Control Unit (PCU) is corrupted. When this fault is triggered, the tractor will enter a 'limp home mode,' which restricts the engine speed to a maximum of 1300 RPM.

• MXM
• MXM120
• MXM130
• MXM140
• MXM155
• MXM175
• MXM190

1. 1

   Check the CAN BUS Wiring: Inspect the CAN BUS wires (Yellow and Green). Ensure they are twisted together properly and are free from interference or chafing.

2. 2

   Check the CAN BUS Terminating Resistor: Reconnect the ECM connector (C316) and measure the resistance between connector C273 pin 1 (5420-G) and C273 pin 2 (5400-Y).

3. 3

   Evaluate Resistance: The resistance should be approximately 120 Ohms. If it is not ~120 Ohms, the terminating resistor inside the Engine Control Module has failed.

1. 1

   Repair or replace CAN BUS harness

   If the CAN BUS wiring is damaged or untwisted, repair or replace the harness as required.

2. 2

   Replace Engine Control Module (ECM)

   If the terminating resistor check fails (does not read ~120 Ohms), remove and replace the Engine Control Module (ECM).

3. 3

   Flash software into ECM

   If the resistance is correct (~120 Ohms), the CAN BUS circuit is okay. You must then download/flash the correct level of software into the Engine Control Module.

4. 4

   Replace fuel injection pump assembly

   If the fault code re-occurs after the software update, the EEPROM inside the PCU is permanently corrupted. Because the PCU is integrated into the injection pump, you must remove and replace the entire fuel injection pump assembly.

5. 5

   Clear error code and test

   Once the repair is complete, clear the error code using the service tool and test the tractor to ensure the 1300 RPM limp mode is resolved.