Case IH 274 – Engine Controller (ENG): Rear Pumping Control Valve current is high

This code indicates a short circuit condition (current too high) in the circuit for the Rear Pumping Control Valve. The Rear Pumping Control Valve is a critical component of the CAPS (Cummins Accumulator Pump System) fuel injection pump, responsible for controlling the pressure in the accumulator by regulating fuel pumped by the rear pumping element.

• MX Magnum
• STX Steiger
• Case IH Magnum Tractors (MX and TG series, e.g., MX210)
• Case Steiger tractors
• Case IH Axial-Flow combines (e.g., 9250/7150)
• Case Puma series

1. 1

   Inspect the wiring harness between the Engine Controller and the CAPS pump, specifically checking for a short circuit to ground or power on pin A15 of the engine controller.

2. 2

   Perform a 'Click Test' using a diagnostic service tool to manually activate the Rear Pumping Control Valve, Front Pumping Control Valve, and Injection Control Valve and listen to see if the valves physically operate (click).

3. 3

   Perform a Cylinder Cutout / Valve Close Angle Test using a diagnostic tool to cut out the rear pumping control valve and compare the results against cutting out the front pumping control valve. The Valve Close Angle (VCA) should not vary by more than 15 degrees crank angle. If the engine dies when one is cut out, the accumulator module has failed.

1. 1

   Read fault codes

   Turn the key switch to the 'ON' position and connect your electronic service tool to read active and inactive fault codes.

2. 2

   Inspect and repair wiring

   Inspect the wiring harness for chafing, melting, or exposed wires leading to the CAPS pump accumulator module. Repair any damaged wiring.

3. 3

   Diagnose valve failure

   If the wiring is intact but the Rear Pumping Control Valve fails the 'click test' or the cylinder cutout test, the valve itself is internally shorted or mechanically failed.

4. 4

   Prepare for module replacement

   The Rear Pumping Control Valve cannot be replaced individually; it is integrated into the Accumulator Module. You must replace the entire Accumulator Module on top of the CAPS fuel pump.

5. 5

   Remove old module

   Remove the old accumulator module from the top of the fuel pump body.

6. 6

   Install new module

   Install the new accumulator module and torque to OEM specifications.

7. 7

   Verify repair

   Clear the inactive fault codes using the electronic service tool and run the engine to verify the repair.