New Holland ENG 3348 – Engine ECU: Multiple State Switch

This fault code indicates an electrical issue with the "Multiple State Switch" circuit. The fault is triggered when the control unit detects an implausible signal, an open circuit, a short to ground, or a short to battery voltage on this switch's circuit.

• New Holland T8.xxx Series tractors
• Various other CNH equipment utilizing the EDC7UC31 or EDC16 engine control units

1. 1

   Check the physical condition of the Multiple State Switch (usually located on the armrest, multi-function handle, or side console) for sticking, physical damage, or liquid intrusion.

2. 2

   Inspect the wiring harness and connectors between the switch and the Engine ECU for chafed wires, corrosion, or loose pins.

3. 3

   Use a multimeter to test the switch circuit for continuity, short to ground, or short to battery voltage.

4. 4

   Connect the CNH Electronic Service Tool (EST) or EASy tool to monitor live data for the Multiple State Switch and verify if the signal state changes when physically toggled.

1. 1

   Power Down

   Turn off the machine, remove the key, and disconnect the negative battery terminal to prevent electrical spikes.

2. 2

   Access the Switch

   Locate the Multiple State Switch (Constant RPM / Drive Mode switch) on the armrest or console. Carefully remove the trim panels required to access the back of the switch.

3. 3

   Disconnect and Test

   Disconnect the electrical connector from the switch. Using a multimeter, test the switch's internal contacts for proper resistance/continuity as you toggle it through its multiple states.

4. 4

   Replace if Faulty

   If the switch fails the continuity test or shows infinite resistance when closed, replace the switch assembly.

5. 5

   Harness Repair (If Applicable)

   If the switch tests good, the fault lies in the wiring. Trace the harness back to the Engine ECU, repairing any broken wires or replacing corroded connector pins.

6. 6

   Reassembly

   Reconnect the switch, reinstall the console trim, and reconnect the battery.

7. 7

   Clear Codes

   Turn the key on, connect the CNH EST diagnostic tool, and clear the inactive ENG 3348 fault code. Test the switch operation to ensure the code does not return.