Case IH tD7 – PCU: Hand Throttle Idle Switch Closed Circuit

Indicates an electrical fault where the idle validation switch on the hand throttle assembly is stuck in the closed position, or the controller is detecting a continuous closed circuit due to a short to ground in the wiring harness. The system cannot verify when the operator has returned the hand throttle to the idle position.

• MXM
• MXM 120
• MXM 130
• MXM 140
• MXM 155
• MXM 175
• MXM 190
• Magnum 235
• Magnum 245
• Magnum 255
• Magnum 275
• Magnum 305
• Magnum 335
• Magnum 340
• Puma 140
• Puma 165
• Puma 180
• Puma 195
• Puma 210
• Puma 225

1. 1

   Turn the keyswitch OFF and disconnect the battery (or pull the relevant fuse) to prevent false readings

2. 2

   Disconnect the connector at the hand throttle position sensor/switch and inspect the pins for corrosion, bent terminals, or moisture

3. 3

   Using a multimeter set to Ohms, test the idle switch pins on the throttle assembly. The circuit should open and close as you move the throttle off and onto the idle position. Continuous continuity indicates an internal failure

4. 4

   If the switch tests fine, check the wiring harness between the throttle connector and the PCU for shorts to ground using a multimeter

1. 1

   Wiring Repair

   If a short to ground is found in the harness, trace the routing to find the chafed or melted wire. Cut away the damaged section, splice in a new wire using proper crimps/solder, and seal it tightly with vinyl insulation tape or heat shrink.

2. 2

   Component Replacement

   If the switch failed, remove the side console/trim panels to access the hand throttle assembly. Unbolt the faulty hand throttle potentiometer/switch assembly and install the replacement unit. Reconnect the wiring harness.

3. 3

   Recalibration

   Any time a potentiometer is replaced or a mechanical repair is effected on the throttle, the system must be recalibrated. Enter the H-Menu on the dash display and run the calibration setup (often found in mode HA or after an H8 memory reset) to teach the PCU the new minimum and maximum voltage values of the new throttle switch.