Case IH 397 – Engine Control Module (ECM): Rear Fueling current is too high

The Engine Control Module (ECM) has detected an electrical current draw from the Rear Fueling Actuator (a solenoid located inside the Injection Control Valve on top of the fuel injection pump) that exceeds the maximum allowable limit. This condition is almost always caused by a short circuit in the engine wiring harness, a short to ground, or an internal short/failure of the actuator's electromagnetic coil (stator).

• MX Magnum
• STX Steiger
• Magnum MX240
• Magnum MX255
• Magnum MX270
• Magnum MX285
• Steiger STX series
• Patriot Sprayer 4420

1. 1

   Wiring Harness Inspection: Inspect the wiring harness running from the ECM to the CAPS pump Injection Control Valve (ICV). Look for chafed wires, melted insulation, or areas where the harness may be shorting to the engine block.

2. 2

   Stator Resistance Test: Disconnect the electrical connector at the CAPS pump ICV. Use a multimeter to measure the resistance (ohms) of the rear fueling actuator pins. A dead short (near zero ohms) confirms the internal stator coil has failed.

3. 3

   Click Test: Using a diagnostic service tool, perform an ICV 'Click Test' to manually actuate the internal solenoids and listen for proper mechanical operation.

4. 4

   Transient Suppressor Check: Locate the Transient Suppressor (a protective diode block usually mounted on the passenger side of the engine block near the compressor). It must be tested or preemptively replaced if a stator failure has occurred.

1. 1

   Disconnect Power

   Disconnect the machine's batteries to prevent electrical arcing or accidental ECM damage.

2. 2

   Clean Pump Area

   Thoroughly steam-clean the pump area before opening the fuel system, as the CAPS pump is highly sensitive to contamination.

3. 3

   Replace the Transient Suppressor

   If the stator has shorted, unbolt and replace the Transient Suppressor on the engine block. Failing to do this will likely cause the new stator to short out immediately.

4. 4

   Remove the ICV / Stator

   Disconnect the wiring harness from the top of the CAPS pump. Remove the mounting bolts holding the Injection Control Valve (ICV) / Stator assembly to the pump accumulator.

5. 5

   Install the New Stator/ICV

   Install the replacement stator kit or complete ICV assembly. Ensure all O-rings and sealing washers are perfectly seated to prevent high-pressure fuel leaks.

6. 6

   Reassembly

   Torque the mounting bolts to OEM specifications. Reconnect the wiring harness.

7. 7

   Prime and Clear

   Reconnect the batteries, cycle the key to allow the electric lift pump to prime the system, and clear the fault codes using a diagnostic tool.