New Holland ENG 274 – Engine Controller (Engine ECU): Rear Pumping Control Valve current is high

The engine controller has detected a short circuit or an excessive electrical current draw on the circuit operating the rear pumping control valve.

• T8000 series tractors

1. 1

   Check the wiring harness between the Engine ECU and the CAPS pump accumulator module for a short to ground or a short to voltage on the rear pumping control valve circuit.

2. 2

   Use an electronic service tool to perform a 'click test' on the pumping control valves to verify electrical continuity and solenoid operation.

3. 3

   Perform a Valve Cutout Test using diagnostic software to compare the engine's Valve Close Angle (VCA) when the rear pumping control valve is cut out versus the front. The VCA should not vary by more than 15 degrees crank angle.

4. 4

   Perform an Engine Stall Check: if the engine dies completely when one of the pumping control valves is cut out during the test, it confirms a failure in the accumulator module.

1. 1

   Clear inactive codes

   Turn the key switch to the 'ON' position and use an electronic service tool to clear any inactive fault codes.

2. 2

   Test wiring harness

   Disconnect the wiring harness at the CAPS fuel pump accumulator module and the Engine ECU. Test the rear pumping control valve circuit for shorts.

3. 3

   Repair wiring

   If a wiring short is found, repair or replace the damaged section of the engine wiring harness.

4. 4

   Identify internal fault

   If the wiring tests good, the fault is internal to the rear pumping control valve solenoid.

5. 5

   Determine replacement need

   The rear pumping control valve cannot be serviced individually; it is integrated into the CAPS accumulator module. You must replace the entire accumulator module assembly.

6. 6

   Remove defective module

   Remove the defective accumulator module from the top of the CAPS fuel pump body.

7. 7

   Install new module

   Install the new accumulator module kit, ensuring all mating surfaces are clean and new seals are used.

8. 8

   Finalize repair

   Reconnect the wiring harness, prime the fuel system, and clear any remaining active fault codes.