Case IH F85 – Transmission Control Module (TCM): Pressure Indicated On Reverse Clutch Pressure Switch When The Clutch Solenoids Are Off

The transmission controller is receiving a signal from the reverse clutch pressure switch indicating that hydraulic pressure is present, even though the controller has not commanded the reverse clutch solenoid to open/energize. Because this mismatch could cause unintended movement or internal transmission damage, the system automatically disables the transmission as a safety precaution.

• MXM
• MXM 120
• MXM 130
• MXM 140
• MXM 155
• MXM 175
• MXM 190
• TM115
• TM120
• TM125
• TM130
• TM135
• TM140
• TM150
• TM155
• TM165
• TM175
• TM190

1. 1

   Cycle power by turning the key OFF, then ON, and recheck if the code persists.

2. 2

   With the engine off, remove the tractor's floorpan to access the transmission pressure switches.

3. 3

   Disconnect the reverse range pressure switch and check for continuity using a multi-meter. With the engine off and no hydraulic pressure, it should indicate an open circuit.

4. 4

   If the switch correctly shows an open circuit when unpressurized, trace the wiring harness back to the controller to find and repair a short circuit to the switch.

1. 1

   Prepare tractor

   Park the tractor on a level surface, turn the engine off, and relieve any residual hydraulic pressure.

2. 2

   Remove floorpan

   Remove the cab floorpan to gain access to the top/side of the transmission housing where the clutch pressure switches are located.

3. 3

   Disconnect harness

   Locate the reverse clutch pressure switch and disconnect its electrical harness.

4. 4

   Remove faulty switch

   Unthread the faulty pressure switch from the transmission port. Have a rag ready to catch minor oil seepage.

5. 5

   Install new switch

   Thread the new pressure switch into the port and tighten to OEM torque specifications.

6. 6

   Reconnect harness

   Reconnect the electrical harness.

7. 7

   Verify code

   Turn the key ON to verify that the F85 code has cleared.

8. 8

   Reinstall and test drive

   Reinstall the floorpan and test drive the tractor to ensure the transmission engages in reverse properly and no codes return.