Case IH 3597-04 - ICM – ICM: ECU Power Output Supply Voltage #1 - Voltage Below Normal, Or Shorted To Low Source

Indicates a short to ground between the electronic control unit and the connected component, an unusually weak battery supply causing injector pull-in/hold currents to deviate, or an internal hardware defect in the control unit.

• MAGNUM AFS Connect
• Case IH Axial-Flow 5130
• Case IH Axial-Flow 6130
• Case IH Axial-Flow 7130
• Case IH Axial-Flow 5140
• Case IH Axial-Flow 6140
• Case IH Axial-Flow 7140
• Case IH Axial-Flow 5150
• Case IH Axial-Flow 6150
• Case IH Axial-Flow 7150
• Case IH Magnum Tractors (AFS network)
• Case IH Steiger Tractors (AFS network)

1. 1

   Verify that battery voltage does not drop below 6.2 VDC during engine cranking and check for high resistance in the module's supply or return circuits.

2. 2

   Inspect the wiring harness leading from the ICM to its connected components for signs of chafing, melted insulation, or pinched wires that would cause a short to ground.

3. 3

   Switch the ignition OFF, unplug the control unit, and measure the line resistance of the connected components using a terminal tester.

4. 4

   Inspect the battery power wire, fuses, and firewall ground nuts for the control modules, as loose grounds can simulate a shorted/low voltage condition.

1. 1

   Disconnect Power

   Turn the ignition OFF and disconnect the negative battery cable to prevent further hardware damage.

2. 2

   Isolate the Short

   Disconnect the harness from the ICM. Using a multimeter, check the continuity between the power output pins on the harness connector and the chassis ground.

3. 3

   Repair Wiring

   If continuity to ground is found on a power wire, trace the harness to locate the chafe or pinch point. Repair the damaged wire using OEM-approved heat-shrink connectors, or replace the affected harness section.

4. 4

   Test the Module

   If the wiring harness tests perfectly fine (no short to ground), the fault lies within the ICM itself (internal hardware defect/short).

5. 5

   Replace the ICM

   Remove the mounting hardware securing the ICM. Install the new module and reconnect the harnesses.

6. 6

   Clear Codes & Calibrate

   Reconnect the battery, turn the key ON, and use the CNH Electronic Service Tool (EST) to clear the inactive fault codes. If a new ICM was installed, it may require dealer programming/flashing to sync with the machine's CAN bus network.