Case IH PAC – Engine Control Module (ECM): PCU CAN Bus Off, Data Valid But Above Normal Range.

This code indicates a loss of communication or a faulty connection between the Engine Control Module (ECM) and the Pump Control Unit (PCU). When this code is active, the engine enters a 'limp-home' condition, engine performance and fuel quantity are reduced, and engine speed is restricted to a maximum of 1300 RPM.

• MXM
• MXM 120
• MXM 130
• MXM 140
• MXM 155
• MXM 175
• MXM 190
• TM120
• TM190

1. 1

   Turn the power OFF and the keyswitch OFF. Disconnect the battery or pull the relevant fuse.

2. 2

   Disconnect the connectors at both the ECM and the PCU to isolate the circuit and prevent false multimeter readings.

3. 3

   Visually inspect the connectors at the ECM and the injection pump for corrosion, bent pins, moisture, or backed-out terminals.

4. 4

   Using a multimeter set to Ohms, test the wiring harness between the ECM and the PCU for continuity (open circuits), short to ground, and short to 12V power source.

1. 1

   Repair wiring

   If the diagnostic checks reveal an open circuit, short, or damaged connector pin, repair the wiring harness using a standard harness repair kit or replace the affected harness section.

2. 2

   Clear and retest

   Reconnect all modules, turn the key on, and check if the tAC (3013-0) code clears.

3. 3

   Test with a known good ECM

   If the wiring is perfectly intact, temporarily connect a test EEM2 controller (ECM) to test PCU functionality. This will trigger a serial number mismatch code (FC 175), but if the original communication code disappears, the original ECM is damaged.

4. 4

   Replace the injection pump / PCU

   If the communication code remains active even with a test ECM, the Bosch VP PCU is internally damaged. Remove the injection pump and send it to a diesel shop for a PCU rebuild, or replace the entire injection pump assembly.

5. 5

   Program new ECM

   If the ECM (EEM2 controller) is replaced, use the OEM Service Tool to couple the new controller to the current injection pump's serial number.