Case IH 2019 – Transmission Control Module (TRANS / TCU): Voltage from the range position switch (R2) is low

The controller is receiving a signal voltage from the R2 transmission range position switch that has dropped below the minimum expected threshold. This condition is typically caused by a short to ground in the wiring harness, a disconnected plug, or an internal failure of the switch itself.

• Farmall
• MX Magnum
• TG
• Puma
• Steiger
• TL Series (TL70A, TL80A, TL90A, TL100A)
• T5 Series (T5030, T5040, T5050, T5060)
• T6/T7 series

1. 1

   Inspect the transmission harness leading to the R2 range position switch for chafed wires, pinched lines, or melted insulation that could cause a short to ground

2. 2

   Disconnect the R2 switch plug and check for water ingress, bent pins, or corrosion

3. 3

   Turn the key to the ON position and probe the harness-side connector to verify if the reference voltage from the TCU is present

4. 4

   Test the R2 switch itself for proper continuity across its operating positions to determine if the internal contacts have failed

1. 1

   Engage the handbrake, switch off all electrical switches, and set the Shuttle control lever to neutral.

   Always park the tractor on level ground in an unobstructed area to prevent sudden movement during transmission work.

2. 2

   Lower the hydraulic lift arms and remote control valve levers, switch off the engine, and place safety wedges under the front and rear wheels.

3. 3

   Locate the R2 Range Position Switch on the transmission housing.

   Exact location varies by model, but it is typically threaded directly into the transmission case near the shift actuators.

4. 4

   Disconnect the electrical pigtail/connector from the switch.

5. 5

   If the wiring is damaged, splice in a new connector pigtail using waterproof heat-shrink connectors.

6. 6

   If the switch is faulty, unscrew the old switch from the transmission housing.

7. 7

   Thread the new R2 range position switch into the housing and tighten to the OEM torque specification.

8. 8

   Reconnect the electrical harness.

9. 9

   Clear the fault codes via the diagnostic display.

10. 10

    Run a transmission/clutch calibration routine.

    Depending on the tractor model, replacing transmission sensors may require you to run a transmission/clutch calibration routine to ensure the TCU relearns the engagement points.