Case IH U96 – Transmission Controller (Transmission ECU): Synchro potentiometer signal is out of range for R1 position.

The control module is receiving a voltage signal from the F2/R1 synchronizer potentiometer that falls outside the expected parameters when the transmission attempts to engage the R1 (Reverse 1) position.

• Puma 125
• Puma 140
• Puma 165
• Puma 180
• Puma 195
• Puma 210
• Puma 225 CVX

1. 1

   Check Live Data: Connect the diagnostic tool (or special tool 380000843 to the diagnostic connector to activate the 'H Menu') and observe the displayed F2/R1 potentiometer voltage readings while attempting to shift or calibrate.

2. 2

   Check for Sub-Codes: Look for accompanying transmission fault codes that narrow down the issue, such as 2517, 2518, 2520, 2522, or 2524.

3. 3

   Wiring Inspection: Visually and electrically test the wiring harness between the Transmission Controller and the F2/R1 synchronizer potentiometer and solenoids for chafed wires, corrosion in the connectors, or a short to ground.

4. 4

   Mechanical Verification: Verify if the F2/R1 synchronizer can successfully engage neutral; if electrical readings are normal but the synchronizer won't move, the issue is likely mechanical.

1. 1

   Safety First

   Park the tractor on a level surface, turn off the engine, and ensure all pressure is relieved from the hydraulic circuits before removing any covers or valves.

2. 2

   Harness Repair

   If the multimeter continuity checks reveal an open or shorted wire in the transmission harness leading to the F2/R1 potentiometer or R1 solenoid, repair or replace the damaged wiring section.

3. 3

   Potentiometer Replacement

   If the wiring is intact but the potentiometer readings are erratic or out of range, remove the F2/R1 synchro potentiometer from the transmission valve block/housing and install a new OEM potentiometer.

4. 4

   Driveline Inspection

   If a new potentiometer does not resolve the out-of-range signal and the synchronizer still fails to move into the R1 position, the transmission must be partially disassembled to inspect the F2/R1 synchronizer assembly, shift forks, and clutch packs for mechanical binding or failure.

5. 5

   Calibration

   After replacing the potentiometer, repairing wiring, or fixing a mechanical driveline issue, you MUST perform a transmission synchronizer calibration using the tractor's diagnostic menu or the CNH EST software so the ECU can learn the new potentiometer voltage limits for the R1 position.