Case IH 167 – TMF (Transmission Management Function): Current sensed when the PTO driver is off.

The control module is detecting electrical current flowing through the Power Take-Off (PTO) solenoid circuit even though the PTO switch in the cab is in the "OFF" position. This is a critical safety fault, as a short to power could cause the PTO to engage unexpectedly or prevent it from disengaging.

• Magnum
• Case IH Magnum Series (MX and Series 4)
• Case IH Steiger / STX Series
• Case IH TG Series
• Case IH Maxxum Series
• Case IH Puma Series
• Case IH Farmall Series

1. 1

   Check the PTO ON/OFF switch on the armrest for internal voltage leaks using a multimeter to verify no voltage passes when OFF.

2. 2

   Inspect the wiring harness for a short to power by disconnecting the harness at the PTO solenoid, turning the key ON (engine OFF, PTO OFF), and probing for 12V.

3. 3

   Test the PTO solenoid coil resistance with a multimeter to check for an internal short causing erratic current readings.

4. 4

   Listen for relay clicks inside the controller (back of tractor) when toggling the PTO switch to check for a sticking relay.

1. 1

   Disconnect Power

   Turn off the tractor and disconnect the negative battery cable to prevent electrical spikes.

2. 2

   Repair Wiring

   If the diagnostic checks revealed a short to power in the harness, trace the wire from the solenoid back to the cab. Repair any chafed wires rubbing against the chassis or other live wires.

3. 3

   Replace the PTO Switch

   Carefully pry up the armrest console panel. Disconnect the electrical connector from the bottom of the PTO switch. Depress the retaining tabs on the switch and push it up through the console. Snap the new switch into place and reconnect the harness.

4. 4

   Replace the PTO Solenoid

   Clean the area around the PTO valve block on the transmission to prevent dirt ingress. Unplug the electrical connector from the PTO solenoid. Unscrew the retaining nut or bolts holding the solenoid coil to the valve stem. Slide the old solenoid off. (If replacing the entire cartridge valve, unthread it from the housing and catch any residual hydraulic fluid). Install the new solenoid, torque to OEM specifications, and reconnect the harness.

5. 5

   Clear Codes

   Reconnect the battery, turn the key on, and use the tractor's diagnostic menu or a service tool to clear the TMF 167 fault code. Test PTO engagement and disengagement safely.