Case IH 56 – Transmission ECM: FORWARD_SW_LO_ERR - Power Shuttle FNR Lever Forward Position Switch Short to Ground or Open Circuit

The system logs this fault when the ECM detects that the voltage has dropped below 0.7 volts at ECM connector 2, pin 26.

• JXC
• TN Series (TNDA and TNSA Series)
• Maxxum Series (110, 115, 120, 125, 130, 140 Tier 3)
• MXU Series (100-135)
• Magnum Series
• Puma Series

1. 1

   Check ECM Voltage: Verify if the voltage is indeed below 0.7 volts at ECM connector 2, pin 26.

2. 2

   Harness Continuity Test (Pin 20): Test the wiring harness for an open circuit or a short to ground between ECM connector 2, pin 20, and the Power Shuttle FNR Lever Forward Position Switch.

3. 3

   Harness Continuity Test (Pin 26): Test the wiring between the FNR Lever Forward Position Switch and ECM connector 2, pin 26.

4. 4

   Switch Terminal Test: Disconnect the FNR lever and test for continuity across the switch terminals when the lever is moved into the forward position to determine if the internal contacts have failed.

1. 1

   Power Down

   Turn off the tractor, remove the key, and disconnect the battery to prevent electrical shorts during repair.

2. 2

   Access the Switch

   Remove the steering column shrouds/dash panels to access the base of the steering-wheel-mounted FNR shuttle lever.

3. 3

   Disconnect the Harness

   Unplug the connection cable with the plug from the FNR lever assembly.

4. 4

   Repair Wiring

   If the diagnostic checks revealed a short or open circuit in the harness between the switch and the ECM, repair the damaged wire or replace the connector pins.

5. 5

   Replace the FNR Lever

   If the wiring tests good but the switch fails the continuity test, unbolt the FNR lever assembly from the steering column mounting bracket. Install the new FNR lever assembly.

6. 6

   Reassembly

   Reconnect the electrical plug, reinstall the steering column covers, and reconnect the battery.

7. 7

   Clear Codes

   Turn the key on and use the diagnostic tool or onboard display to clear the inactive fault code 56. Test the forward engagement to ensure the code does not return.