Case IH F89 – Transmission Controller: Creeper Potentiometer Open Circuit Or Short To Ground

The controller is not receiving the correct voltage signal from the creeper potentiometer, detecting either a complete break in the wiring (open circuit) or a wire that is improperly touching the chassis/ground (short to ground).

• MXM
• Case IH MXM 120
• Case IH MXM 130
• Case IH MXM 140
• Case IH MXM 155
• Case IH MXM 175
• Case IH MXM 190
• Case IH Puma 125
• Case IH Puma 140
• Case IH Puma 185
• Case IH Puma 200
• Case IH Puma 210
• Case IH Puma 220
• Case IH Puma 240
• Case IH Maxxum 100 through 180

1. 1

   Inspect the wiring harness leading to the creeper potentiometer for any visible breaks, chafing, or pinched wires that could cause a short to ground or an open circuit.

2. 2

   Perform a Key-On Test by turning the key switch to the ON position, disconnecting the creeper potentiometer, and then re-connecting it to see if the transmission controller registers the state change.

3. 3

   Check for accompanying codes such as F24, E24, or 24, which indicate that the non-volatile memory has been reset or that the transmission requires a mandatory calibration.

1. 1

   Resolve Wiring Issues

   If the diagnostic checks reveal a broken wire or a short to ground in the harness, repair the damaged section of the wiring or replace the connector pigtail.

2. 2

   Replace the Potentiometer

   If the wiring and 5V reference circuits are intact but the F89 code remains active, the internal track of the creeper potentiometer has failed. Remove and replace the creeper potentiometer.

3. 3

   Perform Transmission Calibration

   A Transmission/EDC Calibration setup procedure is required whenever a potentiometer has been replaced, a PWM solenoid valve has been replaced, or a mechanical repair has been effected. Park the tractor on level ground with wheels blocked. Initiate calibration by holding the High and Low range buttons while starting the engine until 'CAL' appears on the transmission display, then set the engine speed to 1200 RPM.