New Holland ENG 328 – Engine Controller (ECM / Engine ECU): Rear Pumping element is failed.

This code indicates a malfunction or failure in the rear pumping element of the CAPS (Cummins Accumulator Pump System) fuel injection pump. While the code points to a mechanical failure of the pumping element itself, it is frequently triggered by severe fuel restriction or air entering the fuel system.

• TG210
• TG230
• TG255
• TG285
• TJ275
• TJ325
• TJ450
• MX180
• MX240
• MX255
• MX270
• MX285
• STX Steiger series

1. 1

   Inspect and replace the primary and secondary fuel filters to rule out severe fuel restriction.

2. 2

   Check the fuel lines between the tank and the CAPS pump for air ingress, kinks, collapsed hoses, or rubber that has gone mushy from hydraulic leaks.

3. 3

   Perform a diagnostic 'click test' on the front and rear pumping control valve solenoids located on top of the accumulator. If the rear solenoid does not click, the issue may be the control valve/stator.

4. 4

   Check the transient suppressor for failure, as this can cause erratic pump behavior and derate conditions.

1. 1

   Clean the Area

   Thoroughly clean the engine valley and the area around the CAPS pump to prevent debris from entering the open fuel lines.

2. 2

   Relieve Pressure & Disconnect

   Disconnect the battery. Relieve any residual fuel pressure. Disconnect the individual high-pressure fuel lines running from the pump to the injectors.

3. 3

   Remove the Accumulator/Actuator

   If repairing on-engine and only the rear pressure valve/stator on top of the accumulator has failed, remove the top accumulator block and replace the faulty solenoids/valves.

4. 4

   Remove the CAPS Pump

   If replacing the whole unit, disconnect the main wiring harness to the pump. Unbolt the pump from the gear drive housing and carefully extract it from the engine.

5. 5

   Install the New Pump & Transient Suppressor

   Mount the replacement CAPS pump. Crucial Step: You must install a new transient suppressor when replacing the pump. Failing to replace the suppressor will often fry the electronics on the new pump.

6. 6

   Reconnect and Bleed

   Reconnect all high-pressure fuel lines and electrical harnesses. Prime the fuel system to bleed out all air before attempting to start the tractor.

7. 7

   Clear Codes

   Clear the ENG 328 code from the ECM and test run the machine under load to verify the repair.