Case IH 3346 – Engine Control Unit (ECU) / Electronic Diesel Control (EDC): Multiple State Switch

Data from the switch is erratic, intermittent, or incorrect. The controller receives an implausible or fluctuating signal from this switch.

• Case IH Magnum series (235 - 340 Series 4)
• Case IH Steiger series
• Case IH Puma series (165, 180, 195, 210, 225)

1. 1

   Use a diagnostic tool (such as CNH Electronic Service Tool / EASy) to monitor the Multiple State Switch input to the ECU for dropouts or erratic fluctuations

2. 2

   Inspect the physical condition of the constant engine speed/cruise control switches or the multi-function handle on the armrest for sticking buttons or physical damage

3. 3

   Check for related electrical fault codes (such as 3347, 3348, or 3349) that might narrow down the specific circuit issue

4. 4

   Inspect the wiring harness between the Multiple State Switch and the Engine ECU (passenger input #06) for chafed wires, loose connector pins, or corrosion

1. 1

   Power down the machine and disconnect the battery to prevent electrical shorts during testing.

   Power down the machine and disconnect the battery to prevent electrical shorts during testing.

2. 2

   Gain access to the Multiple State Switch, which is typically located on the right-hand armrest console (integrated into the multi-function handle or as a standalone constant engine RPM rocker switch).

   Gain access to the Multiple State Switch, which is typically located on the right-hand armrest console (integrated into the multi-function handle or as a standalone constant engine RPM rocker switch).

3. 3

   Disconnect the switch's electrical connector.

   Disconnect the switch's electrical connector.

4. 4

   Using a multimeter, test the switch for proper continuity across its various states (e.g., off, set 1, set 2). If the switch readings are erratic or out of specification, the switch assembly must be replaced.

   Using a multimeter, test the switch for proper continuity across its various states (e.g., off, set 1, set 2). If the switch readings are erratic or out of specification, the switch assembly must be replaced.

5. 5

   If the switch tests good, perform a continuity check on the wiring harness from the switch connector back to the Engine ECU pins. Test for shorts to ground and shorts to power.

   If the switch tests good, perform a continuity check on the wiring harness from the switch connector back to the Engine ECU pins. Test for shorts to ground and shorts to power.

6. 6

   Repair any damaged wiring or replace the faulty switch assembly.

   Repair any damaged wiring or replace the faulty switch assembly.

7. 7

   Reconnect all components and the battery.

   Reconnect all components and the battery.

8. 8

   Clear the fault codes using the diagnostic tool and test operate the tractor, cycling through the engine speed states to verify the repair.

   Clear the fault codes using the diagnostic tool and test operate the tractor, cycling through the engine speed states to verify the repair.