Case IH 485 – ENG: Rear Fueling actuator overfueling

The Engine Control Module (ECM) has detected an overfueling condition or an electrical fault (such as low or open current) at the rear fueling actuator circuit.

• MX Magnum
• STX Steiger
• MX240
• MX255
• MX270
• MX285
• MX275
• MX305
• STX275
• STX280
• STX325
• STX330
• 2366
• 2377
• 2388
• 2577
• 2588
• SPX4410
• 4420
• FLX3020
• FLX3510
• Titan 4020
• Titan 4520

1. 1

   Check the electric lift pump (transfer pump) for fuel leaks or loose screws (held by 3 small screws). A failing lift pump allows air to infiltrate the injection system.

2. 2

   Inspect both the inline and spin-on fuel filters to rule out restrictions or contamination.

3. 3

   Inspect the engine harness and connectors leading to the rear fueling actuator on the CAPS pump for chafed wires, loose connections, or shorts.

4. 4

   Measure the gear pump outlet pressure at the diagnostic fitting on the CAPS pump at a rated flow condition.

1. 1

   Address Fuel Supply Issues

   If the lift pump is leaking or sucking air, replace the lift pump and its gasket.

2. 2

   Replace Filters and Prime

   Replace all fuel filters. Before starting the engine, turn the key to the ON position and let the electric lift pump run for 30 seconds to prime the system and purge air.

3. 3

   Repair Wiring

   If the diagnostic checks revealed chafed wires or poor connections at the rear fueling actuator, repair the harness or replace the connector using an approved splice kit and dielectric grease.

4. 4

   Replace the CAPS Pump

   If the wiring, lift pump, and filters are good, the internal rear pumping element or actuator on the CAPS pump has likely failed. Replace the entire CAPS fuel injection pump with a remanufactured unit. You must also replace the Transient Suppressor to protect the new pump's electronics and maintain warranty eligibility.